Chemical mechanical polishing apparatus, polishing liquid detection method, polishing method, and medium

Abstract

The application discloses a chemical mechanical polishing device, a polishing liquid detection method, a polishing method and a medium. The chemical mechanical polishing device comprises a polishing disc, a carrier head for polishing a wafer on the polishing disc, a liquid supply assembly for supplying the carrier head with a polishing liquid, the polishing liquid being distributed on a polishing surface of the polishing disc, a lifting baffle ring provided at an outer periphery of the polishing disc and provided with a Helmholtz coil, the lifting baffle ring having an avoiding position when polishing is stopped and a blocking position when polishing is performed, and when the lifting baffle ring is 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 generation arm for superimposing a pulse magnetic field on the polishing liquid, and a magnetic field detection arm provided between the pulse generation arm and the carrier head and used for detecting a nuclear magnetic resonance signal in response to the pulse magnetic field, so as to determine the distribution of the polishing liquid 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 technical field of semiconductor processing, in particular to a chemical mechanical polishing device, a polishing liquid detection method, a polishing method and a medium. BACKGROUND

[0002] In a chemical mechanical polishing (CMP) process, an alkaline silica polishing liquid is generally used to realize efficient removal of surface materials through chemical-mechanical synergy. Specifically, the alkaline environment promotes chemical reaction of the silicon surface to generate soluble silicate, and the negatively charged silica nanoparticles dispersed in the polishing liquid accelerate the removal of the reaction product and the removal of the surface damage layer through adsorption and mechanical friction.

[0003] The uniformity of the distribution of the polishing liquid on the rotating polishing disc directly affects the concentration of the chemical active substances and the mechanical action strength of the abrasive particles in the contact area between the polishing liquid and the wafer, thereby determining the overall planarization effect and the spatial consistency of the material removal rate. SUMMARY

[0004] Therefore, the present application provides a chemical mechanical polishing device, a polishing liquid detection method, a polishing method and a 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 disc; a carrier head for polishing a wafer on the polishing disc; a liquid supply assembly for supplying a polishing liquid to the carrier head, the polishing liquid being distributed on the polishing surface of the polishing disc; a lifting stop ring provided on the outer periphery of the polishing disc, a Helmholtz coil being provided on the lifting stop ring, the lifting stop ring having a stop position when polishing is stopped and a blocking position when polishing is performed, the polishing surface of the polishing disc being located within the range of the Helmholtz coil when the lifting stop ring is in the blocking position, 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 detection arm provided between the pulse generating arm and the carrier head for detecting a 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.

[0006] Optionally, the chemical mechanical polishing device further comprises: a trimming assembly for trimming the polishing pad on the polishing disc; the liquid supply assembly, the trimming assembly, the pulse generating arm, the magnetic field detection arm and the carrier head are sequentially distributed in the flow direction of the polishing liquid.

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

[0008] Optionally, the pulse generating arm comprises a cantilever, a central vertical rod, a central pulse coil arranged at the lower end of the central vertical rod, an edge vertical rod, and an edge pulse coil arranged 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, and the swing arm of the trimming assembly comprises a clearance groove arranged correspondingly 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.

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

[0011] Optionally, the magnetic field detection arm comprises a vertical rod, a swing arm, and a detection coil arranged at the side of the swing arm away from the vertical rod; the swing arm is used to swing the detection coil above the polishing disc and is coupled with the carrier head in motion to determine the distribution of the polishing liquid corresponding to the swing trajectory.

[0012] The second aspect of the present application provides a polishing liquid detection method applied to a chemical mechanical polishing device, comprising: during polishing, allowing the lifting stop ring to be in a blocking position, the polishing surface of the polishing disc being located within the range of the Helmholtz coil on the lifting stop ring to form a basic magnetic field on the polishing surface; superimposing a pulse magnetic field on the polishing liquid by a pulse generating arm; detecting a nuclear magnetic resonance signal in response to the pulse magnetic field by a magnetic field detection arm arranged between the pulse generating arm and the carrier head; and determining the distribution of the polishing liquid according to the relaxation time data of hydrogen atoms reflected by the nuclear magnetic resonance signal.

[0013] The third aspect of the present application provides a chemical mechanical polishing method applied to a chemical mechanical polishing device, comprising: during polishing, allowing the lifting stop ring to be in a blocking position, the polishing surface of the polishing disc being located within the range of the Helmholtz coil on the lifting stop ring to form a basic magnetic field on the polishing surface; superimposing a pulse magnetic field on the polishing liquid by a pulse generating arm; detecting a nuclear magnetic resonance signal in response to the pulse magnetic field by a magnetic field detection arm arranged 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; and controlling the process of supplying the polishing liquid by a liquid supply assembly and / or controlling the carrier head to polish a wafer on the polishing disc according to the distribution of the polishing liquid.

[0014] The fourth aspect of the present application provides a computer storage medium having a computer program stored thereon, the program being executed by a processor to implement the above method.

[0015] The fifth aspect of the present application provides a computer program product comprising computer instructions instructing a computing device to perform operations corresponding to the above-mentioned method.

[0016] The beneficial effects of the present patent technology mainly lie in the following aspects:

[0017] In terms of polishing liquid distribution detection, through components such as Helmholtz coils, pulse generation arms, and magnetic field detection arms, the distribution of the polishing liquid can be determined in real time during the polishing process, solving the problem of the lack of real-time monitoring capability of the dynamic distribution state of the polishing liquid in existing CMP equipment, enabling the operator to timely understand the state of the polishing liquid. Using the relaxation time data of hydrogen atoms reflected by the nuclear magnetic resonance signal, the accumulation degree of various particles in the polishing liquid can be accurately evaluated, and the distribution of the polishing liquid can be inferred, providing an accurate basis for the optimization of the polishing process, which helps to improve the polishing quality and consistency.

[0018] In addition, this technology not only can detect the distribution of the polishing liquid, but also can analyze the dynamic behavior of the polishing liquid, such as the breakage of abrasive particles, the failure of oxidized components, and the gelation of the polishing liquid, according to the decomposition of the nuclear magnetic resonance signal, and timely alarm or prompt, so as to take corresponding measures to further optimize the polishing process.

[0019] In terms of device structure and cost, this technology realizes the detection function of the distribution of the polishing liquid without major changes to the polishing unit, does not make the overall volume of the polishing unit larger, saves space, and is convenient for modification and upgrading on existing equipment. At the same time, the pulse generation arm reuses the fixing seat of the trimming assembly, reduces the number and cost of components, reduces the implementation difficulty, provides high motion redundancy, and improves the economy and practicality of the device.

[0020] In terms of temperature compensation, this technology establishes a temperature compensation mechanism, acquires the temperature distribution data of the polishing disc in real time, and compensates the nuclear magnetic resonance signal based on the temperature compensation coefficient, effectively suppressing the modulation effect of the relaxation time drift on the signal amplitude caused by temperature fluctuations, improving the accuracy and reliability of the detection, and making the detection result more truly reflect the distribution of the polishing liquid. Based on the intrinsic temperature response modeling of relaxation kinetics, compared with the empirical compensation method, it has stronger physical interpretability and working condition adaptability, can better adapt to different polishing processes and environmental conditions, and enhances the universality and stability of the device. BRIEF DESCRIPTION OF DRAWINGS

[0021] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the accompanying drawings needed to be used in the embodiments or prior art description will be briefly introduced as follows. Obviously, the accompanying drawings in the following description are only some embodiments of the present application, and for those skilled in the art, other drawings can also be obtained based on these drawings.

[0022] Figure 1 is a schematic diagram of a chemical mechanical polishing device according to an embodiment of the present application;

[0023] Figure 2 is a schematic diagram of a chemical mechanical polishing device with an optical measurement device according to an embodiment of the present application;

[0024] Figure 3 is a flowchart of a polishing liquid detection method according to an embodiment of the present application;

[0025] Figure 4 is a schematic diagram of an optical measurement signal collected;

[0026] Figure 5 is a schematic diagram of another optical measurement signal collected;

[0027] Figure 6 is a schematic diagram of an optical measurement signal collected and its characterization of reflectivity;

[0028] Figure 7 is a schematic diagram of another optical measurement signal collected and its characterization of reflectivity;

[0029] Figure 8 is a flowchart of adjusting the output light intensity according to reflectivity according to an embodiment of the present application;

[0030] Figure 9 is a schematic diagram of an optical measurement signal collected under a sample voltage;

[0031] Figure 10 is a flowchart of a polishing liquid detection method according to an embodiment of the present application;

[0032] Figure 11 is a flowchart of a polishing liquid detection method according to an embodiment of the present application;

[0033] Figure 12 is a schematic diagram of an electronic device according to an embodiment of the present application.

[0034] 10, bearing head; 20, polishing disc; 30, liquid supply assembly; 40, dressing assembly; 50, pulse generating arm; 501, cantilever; 502, central upright; 503, central pulse coil; 504, edge pulse coil; 505, edge upright; 60, magnetic field detection arm; 601, base; 602, swing arm; 603, upright; 604, detection coil; 605, shroud; 70, lift stop; 701, air cylinder; 702, seal cap; 703, lift stop body; 704, field excitation upper cable; 705, field excitation lower cable; 401, swing arm shroud; 402, main pulley; 403, first conduit fixing block; 404, belt; 405, second conduit fixing block; 406, sub-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 DESCRIPTION

[0035] In order to make the personnel in the art 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 in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments of the present application. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the embodiments of the present application shall belong to the scope of protection of the embodiments of the present application.

[0036] The terms used in the present application are merely for the purpose of describing particular embodiments and are not intended to limit the present application. As used in the present application and the appended claims, the singular forms "a," "an," and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "and / or," as used herein, refer to and encompass any or all possible combinations of one or more of the associated listed items.

[0037] It should be understood that, although the terms first, second, third, etc. can be used in this application to describe various information, these information should not be limited to these terms. These terms are only used to distinguish one piece of information from another piece of information of the same type. For example, without departing from the scope of the present application, the first information can also be referred to as the second information, and similarly, the second information can also be referred to as the first information. Depending on the context, the word "if" as used herein can be interpreted as "when" or "upon determination" or "in response to determining".

[0038] 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 a part of the embodiments of this application, and not all of them. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application. In the absence of conflict, the following embodiments and their technical features can be combined with each other.

[0039] To illustrate the technical solution described in this invention, the following description will be provided with reference to the accompanying drawings and embodiments.

[0040] In this application, chemical mechanical polishing is also called chemical mechanical planarization, and wafer is also called wafer, silicon wafer, substrate, or substrate, etc., with the same meaning and actual function.

[0041] like Figures 1-7 As shown, the chemical mechanical polishing equipment includes a support head 10 for holding and rotating the wafer w, a polishing disk 20 covered with a polishing pad, and a liquid supply assembly 30 for supplying polishing fluid.

[0042] During chemical mechanical polishing (CMP), the support head 10 presses the wafer w onto the polishing pad covering the surface of the polishing disk 20. The support head 10 rotates and reciprocates radially along the polishing disk 20, gradually removing impurities from the surface of the wafer w in contact with the polishing pad. Simultaneously, the polishing disk 20 rotates, and the liquid supply assembly 30 sprays polishing slurry onto the polishing pad surface. Under the chemical action of the polishing slurry, the relative movement between the support head 10 and the polishing disk 20 causes the wafer w to rub against the polishing pad, thus achieving polishing. During polishing, the dressing assembly 40 is used to dress and activate the surface morphology of the polishing pad. Using the dressing assembly 40, impurity particles remaining on the surface of the polishing pad can be removed, such as abrasive particles in the polishing slurry and waste material detached from the surface of the wafer w. It can also smooth out surface deformation of the polishing pad caused by abrasion.

[0043] Due to the centrifugal effect caused by the high-speed rotation of the polishing disc, the differences in liquid adsorption caused by the porous structure of the polishing pad, and fluctuations in process parameters (pressure, rotation speed), the polishing slurry is prone to local enrichment or depletion, resulting in uneven material removal rates on the wafer surface and even inducing residue accumulation or micro-scratches. However, existing CMP equipment generally lacks the ability to monitor the dynamic distribution of the polishing slurry in real time.

[0044] Therefore, this embodiment provides a real-time monitoring scheme for polishing fluid.

[0045] Specifically, the polishing disc is provided with a lifting stop ring 70, which has an avoiding position for stopping polishing and a blocking position for polishing. When polishing is not performed, the lifting stop ring is in the avoiding position, so that the carrier head can swing in and out of the polishing disc. When polishing is performed, the lifting stop ring is in the blocking position, so as to prevent the polishing liquid on the polishing disc from splashing.

[0046] The lifting stop ring is provided with a Helmholtz coil. When the lifting stop ring is in the blocking position, the polishing surface of the polishing disc is within the range of the Helmholtz coil, so as to form a basic magnetic field on the polishing surface. As shown in Figure 8 , the basic magnetic field can make the hydrogen (H) atoms in the polishing liquid have a relatively fixed magnetic moment, and the hydrogen atoms perform spiral motion around the magnetic field direction B0. At this time, there are two kinds of hydrogen atoms with low energy level and high energy level, and a balance is formed.

[0047] In this embodiment, as shown in Figure 6 , the lifting stop ring 70 includes a cylinder 701, a sealing cover 702, a lifting stop 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. The upper excitation cable 704 and the lower excitation cable 705 are energized to form a Helmholtz coil, and a stable basic magnetic field is formed between the two. In the polishing process, the cylinder 701 drives the lifting stop ring main body 703 to rise, so that the polishing surface on the polishing disc is in the basic magnetic field.

[0048] 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 device further includes a pulse generating arm 50 and a magnetic field detection arm 60 for detection.

[0049] The pulse generating arm is used to superimpose a pulse 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 arranged at the lower end of the central vertical rod, an edge vertical rod, and an edge pulse coil arranged at the lower end of the edge vertical rod. Through the central pulse coil and the edge pulse coil, a pulse magnetic field can be applied to the polishing liquid in the annular range on the polishing disc corresponding to the carrier head, as shown in Figure 7 . The carrier head reciprocates on the polishing disc, and the annular range can be an annular range covering the swing area of the carrier head. The direction of the pulse magnetic field can be B1 as shown in Figure 8 .

[0050] 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 the hydrogen atoms reflected by the nuclear magnetic resonance signal. Specifically, as shown in Figure 5The 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 arranged 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. At the same time, the detection coil 604 is coupled with the carrier head to form a motion. Through electromagnetic induction, the current feedbacks the magnetic field strength of the point, thereby feedbacks the distribution of the polishing liquid. Through the cooperation of the swing arm 602 and the linear module, the detection range of the detection coil 604 can be maximized, and the coverage of the detection coil can be ensured.

[0051] The pulse magnetic field applied by the pulse generation arm has a stage of applying a magnetic field and a stage of removing the magnetic field. When the magnetic field is applied, hydrogen atoms with a relatively fixed magnetic moment are affected by the pulse magnetic field. Some hydrogen atoms will absorb energy and transition from a low energy level to a high energy level, changing from an equilibrium state to an unbalanced state. The equilibrium state and the unbalanced state are shown in FIG. 1. Figure 8 When the magnetic field is removed, the hydrogen atoms will return from the high energy level to the low energy level, and from the unbalanced state to the equilibrium state. The time of this change is called the relaxation time.

[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 is very short. When in a free state, the relaxation time is relatively long. Assuming that there are two substances A and B in the polishing liquid, and the size of B is larger than that of A, 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 particles or contaminants in the polishing liquid accumulate, the proportion of large-size substances in the polishing liquid increases, making the overall relaxation time of the polishing liquid shorter. Thus, the situation of large-size accumulators in the polishing liquid can be obtained through the relaxation time. See FIG. 2. Figure 9 In the two curves, the proportion of large-size substances D in the lower curve is higher than that of C in the upper curve. Alternatively, the relaxation time can be decomposed to obtain the relaxation time corresponding to substances of various sizes, and the proportion of various types of molecules can be directly obtained. In summary, the above-mentioned method can be used to evaluate the solid-liquid proportion of water molecules through relaxation time data, so as to infer the accumulation degree of various particles in the polishing liquid, i.e., the distribution of the polishing liquid.

[0053] In addition to the pulse generating arm and the magnetic field detecting arm, other components are distributed above the polishing disc. For example, the chemical mechanical polishing device further comprises a dressing assembly 40 for dressing the polishing pad on the polishing disc; the liquid supply assembly, the dressing assembly, the pulse generating arm, the magnetic field detecting arm, and the carrier head are sequentially distributed in the polishing liquid flow direction. After the polishing liquid flows out of the liquid supply assembly, it falls on the polishing disc, and the centrifugal force of the self-rotation of the polishing disc causes the polishing liquid to flow in the rotation direction. The dressing assembly, the pulse generating arm, the magnetic field detecting arm, and the carrier head are sequentially arranged in the polishing liquid flow direction, which makes the detection object of the magnetic field detecting arm the polishing liquid about to flow into the lower part of the carrier head, and the detection result is more effective.

[0054] Specifically, the dressing assembly comprises a fixing seat, a swing arm, and the dressing assembly 40, and the pulse generating arm reuses the fixing seat of the dressing assembly, so that a fixing seat specially arranged for the pulse generating arm is no longer needed, thereby reducing the number of components and cost. In addition, since the space on the surface of the polishing disc is limited, the pulse generating arm and the dressing assembly share a fixing seat, which can minimize the space occupied by the two during use, reduce the implementation difficulty, and provide a higher motion redundancy.

[0055] For example, the pulse generating arm 50 is added above the dressing assembly 40, which comprises 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 of the polishing disc. The central pulse coil 503 and the edge pulse coil 504 generate a pulse magnetic field perpendicular to the basic magnetic field in a range of 2-14 inches through opposite pulse currents.

[0056] The cantilever 501 of the pulse generating arm 50 is higher than the swing arm of the dressing assembly 40, and the swing arm of the dressing assembly 40 comprises 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.

[0057] The dressing assembly 40 comprises a swing arm cover 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 tensioning wheel 408. 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 assembly 40, and provide avoidance grooves for the central vertical rod and the edge vertical rod of the pulse generating arm 50. The belt tensioning wheel 408 tightens the belt, 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.

[0058] The scheme provided by the embodiment of the present application is as follows: the chemical mechanical polishing device comprises a polishing disc, a carrier head for polishing a wafer on the polishing disc, a liquid supply assembly for supplying polishing liquid to the carrier head, the polishing liquid being distributed on a polishing surface of the polishing disc, a lifting stop ring provided at an outer periphery of the polishing disc and provided with a Helmholtz coil, the lifting stop ring having an avoiding position when polishing is stopped and a blocking position when polishing is performed, the polishing surface of the polishing disc being located within the range of the Helmholtz coil when the lifting stop ring is in the blocking position, so as to form a basic magnetic field on the polishing surface, a pulse generation arm for superimposing a pulsed magnetic field on the polishing liquid, and a magnetic field detection arm provided between the pulse generation arm and the carrier head and used for detecting a nuclear magnetic resonance signal in response to the pulsed magnetic field, so as to determine the distribution of the polishing liquid according to relaxation time data of hydrogen atoms reflected by the nuclear magnetic resonance signal, thereby, through the Helmholtz coil, the pulse generation arm and the magnetic field detection arm, the distribution of the polishing liquid can be determined in the polishing process without making great changes to the polishing unit, the overall volume of the polishing unit is not increased, and the polishing liquid can be detected in real time.

[0059] Referring to Figure 10 , based on the above chemical mechanical polishing device, the embodiment of the present application provides a polishing liquid detection method, comprising:

[0060] S101, in the polishing process, the lifting stop ring is in the blocking position, and the polishing surface of the polishing disc is located within the range of the Helmholtz coil on the lifting stop ring, so as to form a basic magnetic field on the polishing surface.

[0061] S102, a pulsed magnetic field is superimposed on the polishing liquid by the pulse generation arm.

[0062] S103, a nuclear magnetic resonance signal in response to the pulsed magnetic field is detected by the magnetic field detection arm provided between the pulse generation arm and the carrier head.

[0063] S104, the distribution of the polishing liquid is determined according to relaxation time data of hydrogen atoms reflected by the nuclear magnetic resonance signal.

[0064] The pulsed magnetic field applied by the pulse generation arm has a stage of applying a magnetic field and a stage of removing the magnetic field, when the magnetic field is applied, hydrogen atoms with a relatively fixed magnetic moment are affected by the pulsed magnetic field, part of the hydrogen atoms absorb energy and jump from a low energy level to a high energy level, changing from an equilibrium state to an unbalanced state; when the magnetic field is removed, the hydrogen atoms re-enter the low energy level from the high energy level, and change from the unbalanced state to the equilibrium state, and the time of this change is called relaxation time. In the embodiment, a schematic diagram of the pulsed magnetic field can be as shown in Figure 8 .

[0065] 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 is very short. When in a free state, the relaxation time is relatively long. When the abrasive particles or contaminants in the polishing liquid accumulate, the proportion of large-sized substances in the polishing liquid increases, making the overall relaxation time of the polishing liquid shorter. See Figure 9 In the two curves, the proportion of large-sized substances D of the lower curve is higher than that of the upper curve C. Therefore, the relaxation time data can be used to evaluate the solid-liquid proportion of water molecules, so as to infer the accumulation degree of various particles in the polishing liquid, i.e., the distribution of the polishing liquid.

[0066] Further, by combining the pulse period of the pulsed magnetic field, the nuclear magnetic resonance signal can be analyzed and decomposed to obtain multiple relaxation time data.

[0067] Specifically, the nuclear magnetic resonance signal s(T) can be regarded as a superposition of multiple exponential decay curves, and can be split in the longitudinal (B0) and transverse (B1) directions:

[0068]

[0069] where T1,i is the longitudinal relaxation time corresponding to the i-th kind of molecule, representing the energy exchange rate of hydrogen nuclei with the surrounding lattice, which is affected by the concentration of oxidizing agents, the viscosity of the solution, and other chemical environments. High concentration of oxidizing agents (such as H2O2) can accelerate proton exchange and significantly shorten T1.

[0070] T2,j is the transverse relaxation time corresponding to the j-th kind of molecule, representing the dephasing speed of hydrogen spin-spin interaction, which is closely related to the size and surface roughness of abrasive particles. Particle aggregation can enhance the local magnetic field gradient, leading to the broadening of T2 distribution.

[0071] Non-negative matrix factorization (NMF) can be used to decompose the nuclear magnetic resonance signal, and the decay curve can be decomposed into several basis functions (representing typical relaxation time components). Combined with a constrained optimization algorithm, the amplitude (Ai, Bj) and corresponding relaxation time (T1, T2) of each component can be solved.

[0072] The multiple components after decomposition can be physically mapped. Specifically, the relaxation time spectrum after decomposition can be matched with a calibration database and associated to specific substances (such as T2=10ms corresponding to SiO2 abrasive, T2=2ms corresponding to CeO2 abrasive). Thus, the distribution of various substances in the polishing liquid can be determined according to the nuclear magnetic resonance signal.

[0073] Further, the dynamic behavior of the polishing liquid can also be analyzed according to the decomposition of the nuclear magnetic resonance signal, and an alarm can be given.

[0074] T2 main peak shift: if the main peak T2 value increases over time, it indicates that the abrasive particles are gradually broken due to mechanical shear force, and a polishing liquid abrasive particle loss alarm needs to be issued, and the liquid supply component needs to be controlled to increase the liquid supply amount to increase the abrasive particle proportion to maintain the removal rate.

[0075] T1 / T2 ratio anomaly: a sudden decrease in the ratio may indicate that the oxidation components in the polishing liquid are ineffective, at which time the polishing liquid can be prompted to be lost and the liquid supply component can be controlled to increase the liquid supply amount.

[0076] Diffusion coefficient sudden drop: by applying a gradient pulse magnetic field, the diffusion speed of hydrogen atoms in the polishing liquid is measured, and the diffusion coefficient D value is calculated, which can indirectly reflect the abrasive dispersion degree (agglomerated particles will limit molecular diffusion and reduce D value). When the D value is detected to decrease, it indicates that the polishing liquid has gelled (particles are severely agglomerated), and the ultrasonic oscillation module can be started to disperse the particles in the polishing liquid, preventing scratches on the wafer due to particle aggregation in the polishing liquid.

[0077] In this embodiment, referring to Figure 11 It can also include a step S100 of determining the temperature of the polishing disc, and step S104 includes S1041 compensating the relaxation time data based on the temperature and relaxation time relationship curve, and determining the distribution of the polishing liquid according to the compensated relaxation time data.

[0078] According to the temperature of the polishing disc measured by the current temperature sensor, a temperature compensation coefficient aT 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+ aT). The temperature compensation coefficient aT can be calculated by controlling the temperature and measuring the relaxation time data of hydrogen atoms at different temperatures, and then performing data fitting.

[0079] Because the temperature has a significant effect on the relaxation dynamics in the nuclear magnetic resonance detection system, and the chemical mechanical polishing removes the wafer surface based on the combined action of chemistry and mechanics, a large amount of heat is released, which greatly interferes with the above detection system.

[0080] Therefore, a temperature compensation mechanism is established in this application to eliminate the interference of thermal effects on signal acquisition. In specific implementation, the temperature distribution data of the polishing disc is obtained in real time by a temperature sensor, and the nuclear magnetic resonance signal is compensated based on the quantitative model of the temperature compensation coefficient aT, combined with the temperature dependence characteristics of the hydrogen atom relaxation time (T1 / T2). The coefficient represents the relative change rate of the relaxation parameter caused by a unit temperature gradient, and its physical nature reflects the cooperative evolution law of the thermodynamic properties of the medium and the spin-lattice coupling.

[0081] The calibration of the compensation coefficient is realized by a systematic experimental method: a temperature-relaxation time mapping relationship database is established on a precision temperature control platform, and a variable temperature relaxation spectrum measurement technology is used to obtain dynamic response data of a hydrogen atom spin system in a set temperature range. Based on the nonlinear characteristics of the relaxation time with temperature, an optimal temperature compensation function is solved by multi-physical field coupling modeling and nonlinear regression analysis, and the compensation coefficient aT is obtained. Finally, in actual measurement, the compensation coefficient aT can be substituted into the signal correction algorithm, and the original nuclear magnetic resonance signal Sr is subjected to weighted compensation operation (Sc=Sr x (1+aT)) to obtain the compensated nuclear magnetic resonance signal Sc, which effectively suppresses the modulation effect of the relaxation time drift caused by temperature fluctuation on the signal amplitude.

[0082] The core of this compensation strategy is to establish a transfer function between the temperature variable and the relaxation parameter, and its technical advantages are reflected in two aspects: first, dynamic compensation is realized by in-situ temperature monitoring, avoiding the energy consumption and delay problem of the traditional constant temperature control method; second, 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.

[0083] The scheme provided in the application can determine the distribution of the polishing liquid according to the relaxation time data of the hydrogen atoms reflected by the nuclear magnetic resonance signal, so that the distribution of the polishing liquid can be determined in the polishing process without making major changes to the polishing unit by using a Helmholtz coil, a pulse generating arm, a magnetic field detection arm, etc., without increasing the overall volume of the polishing unit, and the polishing liquid can be detected in real time.

[0084] Another embodiment of the application also provides a chemical mechanical polishing method applied to a chemical mechanical polishing device, including: during polishing, allowing a lifting blocking ring to be in a blocking position, a polishing surface of a polishing disc being located within a range of a Helmholtz coil on the lifting blocking ring, and forming a basic magnetic field on the polishing surface; superimposing a pulsed magnetic field on a polishing liquid by a pulse generating arm; detecting a nuclear magnetic resonance signal responding to the pulsed magnetic field by a magnetic field detection arm arranged between the pulse generating arm and a carrier head; determining a distribution of the polishing liquid according to relaxation time data of hydrogen atoms reflected by the nuclear magnetic resonance signal; and controlling a process of supplying the polishing liquid by a liquid supply assembly and / or controlling the carrier head to polish a wafer on the polishing disc according to the distribution of the polishing liquid.

[0085] According to the distribution of the polishing liquid, the process of supplying the polishing liquid by the liquid supply assembly is controlled, which can be specifically controlling the drop point of the polishing liquid, controlling the supply flow of the polishing liquid, and the like according to the distribution of the polishing liquid; and according to the distribution of the polishing liquid, the process of polishing the wafer by the carrier head on the polishing disc is controlled, which can be specifically controlling the pressure of each sub-pressure 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 controlling the rotation speed of the carrier head to control the distribution of the polishing liquid under the carrier head.

[0086] The specific implementation manners of each step in the chemical mechanical polishing method can refer to the above embodiments, and will not be described here.

[0087] In this embodiment, an electronic device 800 is provided, as shown in the figure, the electronic device 800 can include a processor 801, a communications interface 802, a memory 803, and a communications bus 804. Among them: Figure 12

[0088] The processor 801, the communications interface 802, and the memory 803 complete the communication among each other through the communications bus 804.

[0089] The communications interface 802 is configured to communicate with other electronic devices or servers.

[0090] The processor 801 is configured to execute the program 805, and can execute the related steps in the above-mentioned polishing liquid detection method embodiments.

[0091] Specifically, the program 805 can include program code, and the program code includes computer operation instructions.

[0092] The processor 801 can be a CPU, or an application specific integrated circuit (ASIC), or be configured as one or more integrated circuits. The one or more processors included in the smart device can be the same type of processor, such as one or more CPUs; or can be different types of processors, such as one or more CPUs and one or more ASICs.

[0093] The memory 803 is configured to store the program 805. The memory 803 can include a high-speed RAM memory, and can also include a non-volatile memory, for example, at least one disk memory.

[0094] The program 805 can be specifically used for enabling the processor 801 to execute the polishing liquid detection method in the above-mentioned embodiments.​

[0095] In this embodiment, a computer-readable storage medium storing instructions for causing a machine to perform the polishing liquid detection method as described herein is provided. Specifically, a system or apparatus equipped with a storage medium on which a software program code for realizing the functions of any of the above-described embodiments is stored, and a computer (or CPU or MPU) of the system or apparatus is caused to read out and execute the program code stored in the storage medium.

[0096] In this case, the program code read out from the storage medium itself realizes the functions of the above-described method embodiments, and thus the program code and the storage medium storing the program code constitute a part of the present application.

[0097] The storage medium for providing the program code includes a floppy disk, a hard disk, a magneto-optical disk, an optical disk (such as CD-ROM, CD-R, CD-RW, DVD-ROM, DVD-RAM, DVD-RW, DVD+RW), a magnetic tape, a non-volatile memory card, and a ROM. Alternatively, the program code can be downloaded from a server computer through a communication network.

[0098] In this embodiment, a computer program product is provided, which includes computer instructions instructing a computing device to perform the operations corresponding to the above-described method embodiments.

[0099] It should be noted that, according to the needs of implementation, each component / step described in the embodiments of the present application can be split into more components / steps, or two or more components / steps or parts of the operations of the components / steps can be combined into a new component / step, to achieve the purpose of the embodiments of the present application.

[0100] The above-described method according to the embodiments of the present application can be implemented in hardware, firmware, or as software or computer code that can be stored in a recording medium such as a CD ROM, a RAM, a floppy disk, a hard disk, or a magneto-optical disk, or be downloaded from a network through a network download and originally stored in a remote recording medium or a non-transitory machine-readable medium and then stored in a local recording medium, so that the method described herein can be processed by such software on a recording medium using a general computer, a special purpose processor, or programmable or special purpose hardware such as an ASIC or an FPGA. It can be understood that the computer, the processor, the microprocessor controller, or the programmable hardware includes a storage component (for example, RAM, ROM, flash memory, etc.) that can store or receive software or computer code, which, when accessed and executed by the computer, the processor, or the hardware, realizes the method described herein. In addition, when a general computer accesses the code for realizing the method shown herein, the execution of the code will convert the general computer into a special purpose computer for executing the method shown herein.

[0101] Although the present application has been shown and described with respect to one or more implementations, equivalent alterations and modifications will occur to others skilled in the art based on the foregoing description and accompanying drawings. The present application includes all such modifications and alterations and is limited only by the scope of the following claims. In particular regard to the various functions performed by the above described components, the terms (including a reference to a "means") used to describe such components are intended to correspond, unless otherwise indicated, to any component which performs the specified function of the described component (e.g., a functionally equivalent

[0102] That is, the above-described embodiments are merely exemplary implementations of the present application, and do not limit the scope of the patent of the present application, and equivalent structures or equivalent processes of the embodiments of the present application made on the basis of the above-described description and the accompanying drawings, for example, mutual combination of technical features of the embodiments, or direct or indirect use of the technical features in other related technical fields, are also included in the scope of the patent of the present application.

[0103] In addition, the terms "first", "second", etc. are used only for descriptive purposes and are not to be construed as indicating or implying relative importance or an indicated number of the technical features indicated. Thus, the features defined with "first", "second", etc. can explicitly or implicitly include one or more features. In the description of the present application, the meaning of "a plurality of" is two or more, unless otherwise explicitly specified.

[0104] The above description has been presented to enable any person skilled in the art to practice and use the present application. In the above description, various specific details are listed for the purpose of explanation. It will be apparent to those skilled in the art that the present application can be practiced without using these specific details. In other embodiments, well-known processes are not described in detail so as not to obscure the description of the present application with unnecessary detail. Therefore, the present application is not intended to be limited to the embodiments shown, but is to be accorded the widest scope consistent with the principles and features disclosed herein.

[0105] It should be noted that the various embodiments described herein and / or the various features of the embodiments described herein can be combined with each other, as long as there is no conflict, and the combination of the embodiments and / or the features of the embodiments described herein after combination shall fall within the protection scope of the present application.

[0106] 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, and not to limit the scope of the embodiments of the present application, and those skilled in the art can make various improvements and modifications on the basis of the above-described embodiments, and these improvements or modifications shall fall within the protection scope of the present application.

[0107] The above merely provides the specific implementation of the present application, but the protection scope of the present application is not limited to this. Any person skilled in the art can easily think of the changes or replacements within the technical range disclosed by the present application, which should be covered in the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A chemical mechanical polishing device, characterized in that, include: Polishing disc; A bearing head is used to polish the wafer on the polishing disk; A liquid supply assembly is used to supply polishing liquid to the bearing head, and the polishing liquid is distributed on the polishing surface of the polishing disc; A lifting baffle ring is disposed on the outer periphery of the polishing disc, and a Helmholtz coil is disposed thereon. The lifting baffle ring has an avoidance position when polishing is stopped and an obstruction position when polishing is performed. When the lifting baffle ring is in the obstruction position, the polishing surface of the polishing disc is within the range of the Helmholtz coil, so as to form a basic magnetic field on the polishing surface. A pulse generator arm is used to superimpose a pulsed magnetic field onto the polishing slurry; A magnetic field detection arm is disposed between the pulse generating arm and the bearing head to detect the nuclear magnetic resonance signal in response to the pulsed magnetic field, so as to determine the distribution of the polishing fluid based on 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 further includes: a trimming component for trimming the polishing pad on the polishing disc; the liquid supply component, the trimming component, the pulse generating arm, the magnetic field detection arm, and the bearing head are distributed sequentially in the direction of polishing liquid flow.

3. The chemical mechanical polishing equipment according to claim 2, characterized in that, The trimming assembly includes a base, a swing arm, and a trimming component, wherein the pulse generating arm reuses the base of the trimming assembly.

4. The chemical mechanical polishing equipment according to claim 3, characterized in that, The pulse generating arm includes a cantilever, a central pole, a central pulse coil located at the lower end of the central pole, an edge pole, and an edge pulse coil located 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 trimming assembly. The swing arm of the trimming assembly includes clearance grooves corresponding to the central upright and the edge upright, so that the central pulse coil and the edge pulse coil are close to the upper surface of the polishing disc.

6. The chemical mechanical polishing equipment according to claim 1, characterized in that, The pulse generating arm includes a cantilever, a central pole, a central pulse coil located at the lower end of the central pole, an edge pole, and an edge pulse coil located 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 disposed 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 disc and form a motion coupling with the bearing head to determine the distribution of polishing fluid corresponding to the swing trajectory.

8. A method for detecting polishing slurry, applied to chemical mechanical polishing equipment, characterized in that, include: During the polishing process, the lifting retaining ring is positioned at the blocking position, and the polishing surface of the polishing disc is located within the range of the Helmholtz coil on the lifting retaining ring, forming a basic magnetic field on the polishing surface; A pulsed magnetic field is superimposed on the polishing fluid via a pulse generator arm; The nuclear magnetic resonance signal in response to the pulsed magnetic field is detected by a magnetic field detection arm disposed between the pulse generating arm and the bearing head. The distribution of the polishing slurry is determined based on the relaxation time data of hydrogen atoms as reflected by the nuclear magnetic resonance signal.

9. A chemical mechanical polishing method, applied to chemical mechanical polishing equipment, characterized in that, include: During the polishing process, the lifting retaining ring is positioned at the blocking position, and the polishing surface of the polishing disc is located within the range of the Helmholtz coil on the lifting retaining ring, forming a basic magnetic field on the polishing surface; A pulsed magnetic field is superimposed on the polishing fluid via a pulse generator arm; The nuclear magnetic resonance signal in response to the pulsed magnetic field is detected by a magnetic field detection arm disposed between the pulse generating arm and the bearing head. The distribution of the polishing slurry is determined based on the relaxation time data of hydrogen atoms as reflected by the nuclear magnetic resonance signal. Based on the distribution of the polishing slurry, control the process of supplying polishing slurry to the slurry supply assembly, and / or control the carrier head to polish the wafer on the polishing disk.

10. A computer storage medium, characterized in that, It stores a computer program that, when executed by a processor, implements the method as described in claim 8 or 9.

11. A computer program product, characterized in that, Includes computer instructions that instruct a computing device to perform the operation corresponding to the method as described in claim 8 or 9.

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