Abrasive Liquid Monitoring Device, CMP System and Method for Online Monitoring of Abrasive Liquid

Abstract

Embodiments of the present invention relate to a polishing liquid monitoring device, a CMP system, and a method for online monitoring of a polishing liquid. The polishing liquid monitoring device includes a polishing liquid metering unit, a plurality of light sources, and at least one optical detector. The polishing liquid metering unit is configured to hold the polishing liquid. The light sources are configured to emit light beams onto the polishing liquid in the polishing liquid metering unit. The light sources include a first light source configured to emit a first light beam having a first wavelength and a second light source configured to emit a second light beam having a second wavelength longer than the first wavelength. The at least one optical detector is configured to detect the intensity of the light beams scattered by the polishing particles in the polishing liquid.

Description

Technical Field

[0001] Embodiments of the present invention relate to a polishing liquid monitoring device, a CMP system, and a method for online monitoring of a polishing liquid. Background Art

[0002] Chemical mechanical polishing (CMP) has been widely used in the manufacture of semiconductor integrated circuits (ICs). When the particle size of abrasive particles in a polishing liquid becomes larger due to, for example, aggregation, wafers may suffer from scratching problems during CMP. The scratching problems can cause wafer damage and thus seriously affect the yield and reliability. Therefore, it is desirable to develop a polishing liquid monitoring device for online monitoring of the quality of a polishing liquid. Summary of the Invention

[0003] Embodiments of the present invention relate to a polishing liquid monitoring device, which includes: a polishing liquid metering unit configured to accommodate a polishing liquid; a plurality of light sources configured to emit light beams onto the polishing liquid in the polishing liquid metering unit, wherein the light sources include a first light source configured to emit a first light beam having a first wavelength and a second light source configured to emit a second light beam having a second wavelength longer than the first wavelength; and at least one optical detector configured to detect the intensity of the light beam scattered by abrasive particles in the polishing liquid.

[0004] Embodiments of the present invention relate to a chemical mechanical polishing (CMP) system, which includes: at least one CMP device; a first polishing liquid supply unit and a second polishing liquid supply unit configured to supply a polishing liquid to the CMP device; a first polishing liquid supply pipe loop and a second polishing liquid supply pipe loop, the first polishing liquid supply pipe loop being connected to the first polishing liquid supply unit and the at least one CMP device, the second polishing liquid supply pipe loop being connected to the second polishing liquid supply unit and the at least one CMP device; and a polishing liquid monitoring device connected to the first polishing liquid supply pipe loop and the second polishing liquid supply pipe loop and configured to monitor the quality of the polishing liquid.

[0005] Embodiments of the present invention relate to a method for online monitoring of a polishing liquid, which includes: conducting a polishing liquid from a first polishing liquid supply pipe loop to a polishing liquid metering unit; irradiating the polishing liquid accommodated in the polishing liquid metering unit with a light beam; detecting the intensity of the light beam scattered by abrasive particles of the polishing liquid; and obtaining an estimated size of the abrasive particles in the polishing liquid based on the intensity of the light beam scattered by the abrasive particles of the polishing liquid. Description of the Drawings

[0006] Aspects of embodiments of the present disclosure are best understood from the following detailed description when read in conjunction with the accompanying drawings. It should be noted that, in accordance with industry standard practice, various structures are not drawn to scale. In fact, for clarity of discussion, the dimensions of various structures may be arbitrarily increased or decreased.

[0007] Figure 1 FIG. is a schematic diagram of a polishing liquid monitoring device according to some embodiments of the present disclosure.

[0008] Figures 2A to 2C FIG. is a schematic diagram illustrating the angular intensity of different scattered light beams according to some embodiments of the present disclosure.

[0009] Figure 3 FIG. is an enlarged schematic diagram of a polishing liquid monitoring device according to some embodiments of the present disclosure.

[0010] Figure 4 FIG. is a schematic diagram of a polishing liquid monitoring device according to some embodiments of the present disclosure.

[0011] Figure 4A FIG. is a schematic diagram of a light interceptor according to some embodiments of the present disclosure.

[0012] Figure 4B FIG. is a schematic diagram of a light interceptor according to some embodiments of the present disclosure.

[0013] Figure 4C FIG. is a schematic diagram of a polishing liquid monitoring device according to some embodiments of the present disclosure.

[0014] Figure 5 FIG. is a schematic diagram of a polishing liquid monitoring device according to some embodiments of the present disclosure.

[0015] Figure 5A FIG. is an enlarged schematic diagram of an optical lens according to some embodiments of the present disclosure.

[0016] Figure 6 FIG. is a schematic diagram of a polishing liquid monitoring device according to some embodiments of the present disclosure.

[0017] Figure 7 FIG. is a schematic diagram of a polishing liquid monitoring device according to some embodiments of the present disclosure.

[0018] Figure 8 FIG. is a schematic diagram of a chemical mechanical polishing (CMP) system 50 according to some embodiments of the present disclosure.

[0019] Figure 8A FIG. is a schematic diagram illustrating a circuit switch of the CMP system.

[0020] Figure 9 FIG. is a flowchart illustrating a method for online monitoring of a polishing liquid and managing a CMP system according to some embodiments of the present disclosure. Detailed implementation manners

[0021] Many different embodiments or examples are provided below for implementing different features of the provided subject matter. Specific examples of elements and arrangements will be described below to simplify the present disclosure. Of course, these are only examples and are not intended to be limiting. For example, in the following description, forming a first member above or on a second member may include embodiments in which the first member and the second member are formed in direct contact therebetween, and may also include embodiments in which additional members may be formed between the first member and the second member such that the first member and the second member may not be in direct contact. Additionally, the present disclosure may repeat element symbols and / or letters in various examples. This repetition is for simplicity and clarity and does not in itself indicate a relationship between the various embodiments and / or configurations discussed.

[0022] In addition, for ease of description, spatial relative terms such as "below", "beneath", "under", "above", "over", "on", and the like may be used herein to describe the relationship of one element or member to another (other) element or member, as illustrated in the figures. In addition to the orientation depicted in the figures, spatial relative terms are also intended to encompass different orientations of the device in use or operation. The device may be oriented in other ways (rotated 90 degrees or in other orientations) and the spatial relative descriptors used herein may thus be interpreted accordingly.

[0023] As used herein, terms such as "first", "second", and "third" describe various elements, components, regions, layers, and / or sections, and these should not be limited by these terms. These terms may be used only to distinguish one element, component, region, layer, or section from another. Unless the context clearly indicates otherwise, terms such as "first", "second", and "third" used herein do not imply a sequence or order.

[0024] As used herein, the terms "about", "substantially", "substantially", and "approximately" are used to describe and account for small variations. When used in connection with an event or situation, the terms may refer to examples in which the event or situation occurs exactly and examples in which the event or situation occurs very nearly.

[0025] Chemical mechanical polishing (CMP) is an operation that uses a combination of chemical and mechanical forces to smooth a surface. CMP can be regarded as a hybrid of chemical etching and abrasive polishing. The CMP operation uses a slurry containing abrasives and corrosive chemicals in combination with a polishing pad and retainer ring. The polishing pad and the wafer are pressed together by a polishing head and held in place by the retainer ring. The polishing head can rotate about different axes of rotation, which removes material and tends to smooth any irregular surface topography to make the wafer planar or flat. This planar or flat surface can facilitate the formation of successive components. The slurry used in a CMP operation and / or CMP equipment is recycled and reused in another CMP operation and / or CMP equipment. Thus, the abrasive particles in the slurry can grow larger due to (for example) aggregation or the amount of large residues can increase in the slurry. Aggregated abrasive particles having a size larger than the reference size of standard abrasive particles will scratch the wafer during the CMP operation and cause wafer damage and yield loss.

[0026] In some embodiments of the present disclosure, a slurry monitoring device and an on-line slurry monitoring method are provided. The slurry monitoring device is configured to optically detect the particle sizes of abrasive particles and other solid particles in the slurry and can thus detect particle aggregation at an early stage.

[0027] In some embodiments of the present disclosure, a CMP system is also provided. The CMP system includes two or more slurry supply units and their respective slurry supply pipe circuits, and the slurry monitoring device is installed between and in communication with these slurry supply pipe circuits. After oversized abrasive particles or residues are detected by the slurry monitoring device, the slurry supply pipe circuit in which the oversized abrasive particles or residues are detected is disconnected from the CMP equipment so that the non-fresh slurry is not delivered to the CMP equipment, and another slurry supply pipe circuit is connected to the CMP equipment to supply fresh slurry to the CMP equipment.

[0028] Figure 1 is a schematic diagram of a slurry monitoring device 1 according to some embodiments of the present disclosure. As Figure 1As shown, the slurry monitoring device 1 includes a slurry metering unit 12, at least one light source 14, and at least one optical detector 16. The slurry metering unit 12 is a container configured to hold the slurry 20. The slurry metering unit 12 may include (but is not limited to) a cube shape. The material of the slurry metering unit 12 may include glass or other suitable transparent materials. At least one light source 14 is configured to emit a light beam LB onto the slurry 20 in the slurry metering unit 12. In some embodiments, at least one light source 14 may include (but is not limited to) a light-emitting diode (LED), such as a blue laser LED. For example, the slurry monitoring device 1 may include four blue laser LEDs that can emit a light beam LB having a wavelength of about 380 nm to about 450 nm. At least one optical detector 16 is configured to detect the intensity of the light beam LB scattered by the abrasive particles in the slurry 20. In some embodiments, at least one optical detector 16 may include (but is not limited to) a photodiode (PD). For example, the slurry monitoring device 1 may include four photodiodes to detect the intensity of the light beam LB emitted by the four blue laser LEDs and scattered by the abrasive particles in the slurry 20. The intensity detected by the optical detector 16 may be converted into an electrical signal 16S. The electrical signal 16S of the intensity of the light beam LB detected by the optical detector 16 may be amplified by an amplifier and delivered to a controller for analysis. In some embodiments, the slurry metering unit 12, at least one light source 14, and at least one optical detector 16 are enclosed by a black box 18 to reduce optical noise.

[0029] In some embodiments, the slurry metering unit 12 may include a first side 121 and a second side 122 that face each other, and a third side 123 and a fourth side 124 that face each other. The inlet 20A of the slurry 20 may be placed on the first side 121 of the slurry metering unit 12, and the outlet 20B of the slurry 20 may be placed on the second side 122 of the slurry metering unit 12, such that the slurry 20 can flow from the first side 121 to the second side 122 of the slurry metering unit 12. At least one light source 14 may be placed adjacent to the third side 123 of the slurry metering unit 12, and at least one optical detector 16 may be placed adjacent to the fourth side 124 of the slurry metering unit 12. In some embodiments, the inlet 20A and the outlet 20B of the slurry 20 are connected to the slurry supply pipe circuit of a chemical mechanical polishing (CMP) system. Thus, the slurry monitoring device 1 can monitor the slurry 20 of the CMP system online. In some embodiments, the slurry 20 in the slurry metering unit 12 remains stationary during the optical monitoring procedure, but is not limited thereto. For example, valves may be installed in the inlet 20A and the outlet 20B of the slurry 20 to control the flow rate of the slurry 20.

[0030] The Tyndall effect is the scattering of light by particles in a colloid or a very fine suspension. Under the Tyndall effect, longer wavelengths are more transmitted, while shorter wavelengths are more diffusely reflected via scattering. The Tyndall effect is visible when light scattering particles are dispersed in an otherwise light-transmitting medium and when the size (diameter) of the individual particles is slightly below or close to the wavelength of visible light. The slurry 20 includes solvents, chemicals, and abrasive particles and is therefore a colloid or a fine suspension. Therefore, the Tyndall effect can be seen in the slurry 20, and the size of the abrasive particles in the slurry 20 can be detected by identifying the intensity of scattered light in the slurry 20 under the Tyndall effect. Figures 2A to 2C is a schematic diagram illustrating angular intensities of different scattered light beams according to some embodiments of the present disclosure. Figure 2A Schematic representation of the angular intensity of the scattered and / or reflected light beam when the size of the particle is larger than the wavelength of the light beam, Figure 2B schematically depicts the angular intensity of the scattered and / or reflected light beam when the particle size is about 0.25 of the wavelength of the light beam, and Figure 2C Schematic representation of the angular intensity of the scattered and / or reflected light beam when the particle size is about 0.1 of the wavelength of the light beam. Figures 2A to 2C As can be seen in the figure, larger particles scatter the light beam at a smaller angle, while smaller particles scatter the light beam at a larger angle. Therefore, the size of the ground particles in the grinding liquid 20 can be detected by identifying the intensity of the scattered light in the grinding liquid 20 under the Tyndall effect. The freshness of the grinding liquid 20 can be known by detecting the size of the ground particles in the grinding liquid 20.

[0031] In some embodiments, the light source 14 may emit light beams LB of different wavelengths. For example, the first light source may emit a light beam of a shorter wavelength, and the second light source may emit a light beam of a longer wavelength. The group of light sources 14 emitting light beams LB of different wavelengths may be used to dynamically detect changes in the polishing liquid 20. For example, the light beam LB of a shorter wavelength may be used to detect the number of abrasive particles having a first size, which is slightly larger than the standard size of the abrasive particles. The light beam LB of a longer wavelength may be used to detect the number of abrasive particles having a second size larger than the first size. The freshness of the polishing liquid 20 may be accurately monitored by dynamically detecting the ratio of abrasive particles having the first size and the second size.

[0032] Figure 3 FIG. 1 is an enlarged schematic diagram of a grinding liquid monitoring device 1 according to some embodiments of the present disclosure. Figure 3As shown, the abrasive fluid monitoring device 1 includes an abrasive fluid metering unit 12, a light source 14, and an optical detector 16. The abrasive fluid 20 is stored in the abrasive fluid metering unit 12. The light source 14 can be a point light source that emits a light beam LB onto the abrasive fluid 20 in the abrasive fluid metering unit 12. The optical detector 16 includes an optical sensing window 16W. The light beam LB emitted by the light source 14 irradiates the abrasive fluid 20 and is scattered or diffracted by a plurality of abrasive particles 20P to generate a plurality of scattered light beams LB'. The scattered light beams LB' enter the optical sensing window 16W and the intensity of the scattered light beams LB' is detected by the optical detector 16. The estimated size of the abrasive particles 20P in the abrasive fluid 20 can be obtained based on the intensity of the scattered light beams LB'.

[0033] As Figure 3 Schematically illustrated, the light beam LB can encounter two abrasive particles 20P that are close to each other. Therefore, it is necessary to control the distance L between the optical sensing window 16W and the abrasive fluid metering unit 12 to clearly identify two adjacent abrasive particles 20P. In some embodiments, the Rayleigh criterion is applied to set the distance L between the optical sensing window 16W and the abrasive fluid metering unit 12.

[0034] Theoretically, the light beam LB from the point light source 14 in the object diffracts through the lens aperture such that it forms a diffraction pattern in the abrasive particle 20P, which has a central point separated by dark nulls and surrounding bright rings. This pattern is called an Airy pattern, and the central bright lobe is the Airy disk. The angular radius of the Airy disk (measured from the center to the first null) is given as follows:

[0035]

[0036] θ = d / L (2)

[0037] where

[0038] R is the Rayleigh quotient;

[0039] θ is the angular resolution (in radians);

[0040] λ is the wavelength of the light beam;

[0041] d is the diameter of the optical sensing window; and

[0042] L is the distance between the optical sensing window and the abrasive fluid metering unit.

[0043] The minimum Rayleigh quotient R and the minimum distance L between the optical sensing window and the abrasive fluid metering unit can be obtained through the above equation.

[0044] The abrasive particles 20P in the fresh abrasive liquid 20 may have a standard size, and the reference size may be set based on the standard size in the fresh abrasive liquid 20. When the size becomes larger than the reference size, the abrasive particles 20P in the abrasive liquid 20 will cause micro-scratches. In this case, the abrasive liquid 20 can be regarded as a non-fresh abrasive liquid. In some embodiments, the average standard size (diameter) of the abrasive particles in the abrasive liquid 20 for CMP operations is between about 30 nm and about 70 nm, and the reference size can be set to about 100 nm. If the aggregated abrasive particles have a size (diameter) greater than 100 nm, then the abrasive particles will cause micro-scratches and damage the wafer. Therefore, the wavelength of the light beam LB can be selected such that the over-sized abrasive particles in the abrasive liquid 20 can be accurately detected. For example, the wavelength of the light beam LB is about 400 nm.

[0045] For example, the diameter d of the optical sensing window 16W is about 0.5 mm, and the wavelength λ of the light beam LB is about 400 nm. Therefore, the estimated minimum Rayleigh quotient R is about 1000, and the estimated minimum distance L between the optical sensing window 16W and the abrasive liquid metering unit 12 is about 500 mm. The optical resolution of the abrasive liquid monitoring device can be improved (for example) by multiplying the minimum Rayleigh quotient R by 10, and the minimum distance L between the optical sensing window 16W and the abrasive liquid metering unit 12 can be set to be less than about 50 mm. The distance L between the optical sensing window 16W and the abrasive liquid metering unit 12 can be modified based on the optical requirements of the abrasive liquid monitoring device or other considerations. For example, since the minimum distance L between the optical sensing window 16W and the abrasive liquid metering unit 12 can be reduced to less than about 50 mm, the volume of the abrasive liquid monitoring device can be small enough to fit into the CMP system.

[0046] The abrasive liquid monitoring device, CMP system, and on-line abrasive liquid monitoring method of the present disclosure are not limited to the above embodiments, but can be implemented according to other embodiments. To simplify the description and facilitate the comparison of various embodiments of the present disclosure, similar components in the following embodiments are marked with the same element symbols and may not be redundantly described.

[0047] Figure 4 is a schematic diagram of the stacking of the abrasive liquid monitoring device 2 according to some embodiments of the present disclosure, and Figure 4A is a schematic diagram of the light interceptor according to some embodiments of the present disclosure. As Figure 4 shown in Figure 1Compared with the abrasive liquid monitoring device 1, the abrasive liquid monitoring device 2 may further include at least one light chopper 32 disposed between at least one light source 14 and the abrasive liquid metering unit 12 and configured to modify the pulse duration of the light beam LB. Since the nano-sized abrasive particles in the abrasive liquid are non-static, the abrasive particles can move randomly in the abrasive liquid, which is called Brownian motion. Empirically, the speeds of nanoparticles with sizes of 10 nm and 100 nm are about 9 μm / s and about 3 μm / s, respectively. The light chopper 32 is used to compensate for the bias of the signal that adversely affects the light scattering detected by the optical detector due to the unwanted displacement of the abrasive particles caused by Brownian motion.

[0048] The light chopper 32 is a device that periodically interrupts the light beam LB to modify the pulse duration (or angular frequency). In some embodiments, the light chopper 32 may include a rotary shutter. The light chopper 32 is used to modulate the pulse duration of the light beam LB to mitigate the influence of the Brownian motion of the abrasive particles 20P. The reference pulse duration ΔT of the light beam LB can be determined by dividing the particle size by the speed of the particle.

[0049] If the reference size of the abrasive particles 20P is 100 nm and the speed of the 100-nm abrasive particles 20P is 3000 nm / s, then the reference pulse duration ΔT of the light beam LB is about 0.033 seconds. The pulse duration of the light beam LB is set to be less than 0.033 seconds to mitigate the influence of the Brownian motion of the abrasive particles 20P.

[0050] In some embodiments, the abrasive liquid monitoring device 2 may include a plurality of light choppers 32, and the light choppers 32 are arranged to correspond to the plurality of light sources 14. For example, four light choppers 32 are respectively used to modulate the light beams LB of the four light sources 14, as Figure 4A illustrated. The four light sources 14 may emit light beams LB of substantially the same wavelength, and the four light choppers 32 may have the same pulse duration or different pulse durations. The light choppers 32 may include different light choppers 32. In some embodiments, the light choppers 32 may have different pulse durations. For example, the light chopper 32 may include a first light chopper corresponding to the first light source and having a first pulse duration and a second light chopper corresponding to the second light source and having a second pulse duration. In some embodiments, the wavelength of the light beam LB emitted by the first light source is shorter than the wavelength of the light beam LB emitted by the second light source, and the first pulse duration of the first light chopper is longer than the second pulse duration of the second light chopper. The pulse duration of the light chopper 32 can be modified by changing the angular frequency and / or the size of the aperture.

[0051] Figure 4B is a schematic diagram of a light chopper according to some embodiments of the present disclosure. Compared with Figure 4AIn contrast, a light chopper 32 can be used to modulate the light beams LM of all four light sources 14, as Figure 4B illustrated.

[0052] Figure 4C is a schematic diagram of a polishing liquid monitoring device 2' according to some embodiments of the present disclosure. As Figure 4C shown, the number of light sources 14 and the number of light choppers 32 are not equal compared with Figure 4 the polishing liquid monitoring device 2. For example, the light beams LB emitted from all the light sources 14 may have substantially the same wavelength. The light beams LB of the same wavelength emitted from some of the light sources 14 may pass through light choppers 32 having different pulse durations (which include different frequencies and / or different aperture sizes). Additionally, some of the light beams LB emitted from some other light sources 14 do not pass through some of the light choppers 32. Various information about the polishing particles can be obtained by arranging light sources 14 of the same wavelength with and without light choppers 32 having different pulse durations. For example, the arrangement of light sources 14 of the same wavelength with and without light choppers 32 having different pulse durations can be used to dynamically detect changes in the polishing liquid 20. The light beam LB passing through the high-frequency light chopper 32 can be used to detect the number of polishing particles of a first size that is slightly larger than the standard size of the polishing particles. The light beam LB passing through the low-frequency light chopper 32 can be used to detect the number of polishing particles of a second size that is larger than the first size. The freshness of the polishing liquid 20 can be accurately monitored by dynamically detecting the ratio of polishing particles of the first size and the second size.

[0053] Figure 5 is a schematic diagram of a polishing liquid monitoring device 3 according to some embodiments of the present disclosure. As Figure 5 shown, the polishing liquid monitoring device 3 may further include at least one optical lens 34 placed between at least one light source 14 and the polishing liquid metering unit 12 and configured to modify the size (e.g., diameter) of the light spot of the light beam LB irradiated on the polishing liquid 20. In some embodiments, the optical lens 34 may include a focusing lens configured to focus the light beam LB. The polishing liquid monitoring device 3 may include a plurality of optical lenses 34, and the optical lenses 34 are arranged to correspond to the plurality of light sources 14. For example, four optical lenses 34 are respectively used to modify the size of the light spots of the light beams LB of the four light sources 14. In some other embodiments, one optical lens 34 can be used to modify the size of the light spots of all four light sources 14.

[0054] Figure 5A is an enlarged schematic diagram of an optical lens according to some embodiments of the present disclosure. As Figure 5AAs shown, the size of the light spot SP of the light beam LB can be modulated to cover a sufficient number of abrasive particles 20P so that a sufficient number of abrasive particles 20P can be detected to enhance the electrical signal. In some embodiments, the distance 2dp between two adjacent abrasive particles 20P is twice the diameter dp of the abrasive particle 20P. For example, the diameter dp of the abrasive particle 20P is about 100 nm, and the distance 2dp between two adjacent abrasive particles 20P is about 200 nm. It is assumed that more than 100 aggregated particles will be detected to improve the electrical signal. In addition, the specification of the freshness of the abrasive slurry for particle aggregation is less than 5% of the total number of particles, and the area of the light spot SP will cover more than 2000 abrasive particles 20P to ensure that more than 100 aggregated particles can be detected. In some embodiments, the area of the light spot SP is greater than or equal to about 141 um 2 ((3 * 100 nm) 2 * 2000 * π / 4), and the diameter Z of the light spot SP is about 13 um.

[0055] Figure 6 is a schematic diagram of an abrasive slurry monitoring device 4 according to some embodiments of the present disclosure. As Figure 6 shown, the abrasive slurry monitoring device 4 may include at least one light interceptor 32 and at least one optical lens 34 placed between at least one light source 14 and the abrasive slurry metering unit 12. In some embodiments, the light interceptor 32 is placed between at least one light source 14 and at least one optical lens 34. The pulse duration of the light beam LB can be modulated before modulating the size of the light spot of the light beam LB.

[0056] Figure 7 is a schematic diagram of an abrasive slurry monitoring device 5 according to some embodiments of the present disclosure. As Figure 7 shown, the light interceptor 32 is placed between the optical lens 34 and the abrasive slurry metering unit 12. The size of the light spot of the light beam LB is modulated before modulating the pulse duration of the light beam LB.

[0057] Figure 8 is a schematic diagram of a chemical mechanical polishing (CMP) system 50 according to some embodiments of the present disclosure, and Figure 8A is a schematic diagram illustrating the circuit switch of the CMP system. As Figure 8As shown, the CMP system 50 includes at least one CMP device 52, a first abrasive supply unit 541 and a second abrasive supply unit 542 configured to supply an abrasive to the CMP device 52. The CMP system 50 further includes a first abrasive supply pipe loop 561 connected to the first abrasive supply unit 541 and at least one CMP device 52 and a second abrasive supply pipe loop 562 connected to the second abrasive supply unit 542 and at least one CMP device 52. In some embodiments, the CMP system 50 may further include a first bucket 621, a second bucket 622, a mixing tank 64, and pumps 66 and flow meters F installed in the first abrasive supply pipe loop 561 and the second abrasive supply pipe loop 562. Additionally, a valve manifold box (VMB) 68 may be used to switch between the connection of the CMP device 52 and the first abrasive supply pipe loop 561 and the connection of the CMP device 52 and the second abrasive supply pipe loop 562. The abrasive in the first bucket 621 and / or the second bucket 622 may be mixed in the mixing tank 64, and water and / or a solvent may be mixed with the abrasive in the mixing tank 64.

[0058] As Figure 8 As shown, the abrasive monitoring device 60 is connected to the first abrasive supply pipe loop 561 and the second abrasive supply pipe loop 562 and is configured to monitor the quality of the abrasive, such as the freshness of the abrasive. In some embodiments, the abrasive metering unit of the abrasive monitoring device 60 is connected to the abrasive return pipelines of the first abrasive supply pipe loop 561 and the second abrasive supply pipe loop 562, so that the state of the abrasive in the CMP device 52 can be monitored more accurately. The abrasive monitoring device 60 can be selected from any of the abrasive monitoring devices described in the above embodiments, and the details of the abrasive monitoring device 60 will not be redundantly described. Valves (such as a first valve 701 and a second valve 702) may be used to switch between the connection of the abrasive monitoring device 60 and the first abrasive supply pipe loop 561 and the connection of the abrasive monitoring device 60 and the second abrasive supply pipe loop 562. The abrasive monitoring device 60 can drain the abrasive from the first abrasive supply pipe loop 561 or the second abrasive supply pipe loop 562 and monitor the abrasive online. In some embodiments, the CMP system 50 further includes a controller 58 electrically connected to the abrasive monitoring device 60 and configured to control the abrasive monitoring device 60, such as a computer. In some embodiments, the controller 58 may switch between the connection of the abrasive monitoring device 60 and the first abrasive supply pipe loop 561 and the connection of the abrasive monitoring device 60 and the second abrasive supply pipe loop 562.

[0059] As Figure 8AAs shown, if the abrasive fluid monitoring device 60 detects that the freshness of the abrasive fluid in the first abrasive fluid supply pipe circuit 561 is not fresh, the circuit can be switched from the first abrasive fluid supply pipe circuit 561 to the second abrasive fluid supply pipe circuit 562. In this case, the connection between the CMP device 52 and the first abrasive fluid supply pipe circuit 561 is cut off to prevent the non-fresh abrasive fluid from entering the CMP device 52. On the other hand, the connection between the CMP device 52 and the second abrasive fluid supply pipe circuit 562 is turned on to supply fresh abrasive fluid to the CMP device 52. In some other embodiments, the controller 58 can send a notification to the on-duty operator to take appropriate measures.

[0060] Reference Figure 9 。 Figure 9It is a flowchart illustrating a method for online monitoring of abrasive slurry and managing a CMP system according to some embodiments of the present disclosure. In some embodiments, the abrasive slurry is conducted from the first abrasive slurry supply pipe loop 561 to the abrasive slurry metering unit 60. In operation 102, if the estimated size of the abrasive particles 20P is greater than the reference size of the abrasive particles 20P described above, an abrasive slurry freshness alert is received. The abrasive slurry freshness alert can be sent from the controller 58 based on the result of online monitoring of the abrasive slurry. For example, it is detected that the abrasive slurry provided by the first abrasive slurry supply pipe loop 561 is not fresh, which will trigger the abrasive slurry freshness alert. In operation 104, a notification of the abrasive slurry freshness alert is sent to the on-duty operator. In operation 106, the abrasive slurry provided by the first abrasive slurry supply pipe loop 561 is discarded, and a new abrasive slurry mixture is refilled into the first abrasive slurry supply pipe loop 561. In operation 108, the engineer checks whether the online status is normal. If the online status is normal, the first abrasive slurry supply pipe loop 561 remains operational to supply the new abrasive slurry mixture to the CMP apparatus 52, as described in operation 110; if the online status is abnormal (e.g., it is detected that the abrasive slurry does not meet the specifications), the first abrasive slurry supply pipe loop 561 is closed, as described in operation 112. In operation 112, the engineer enhances the online monitoring data and checks whether the online status is normal. If the online status is normal, the first abrasive slurry supply pipe loop 561 remains operational to supply the new abrasive slurry mixture to the CMP apparatus 52, and the abrasive slurry freshness alert ends, as described in operation 114. If the online status is abnormal, the first abrasive slurry supply pipe loop 561 is closed, as described in operation 116. In operation 118, a new batch of abrasive slurry mixture is mixed and conveyed to the second abrasive slurry supply pipe loop 562. In operation 120, the freshness of the new batch of abrasive slurry mixture is checked. If the freshness of the new batch of abrasive slurry mixture is abnormal, the new batch of abrasive slurry mixture is discarded, and another new batch of abrasive slurry mixture is mixed and conveyed to the second abrasive slurry supply pipe loop 562, as described in operation 118. If the freshness of the new batch of abrasive slurry mixture is normal, the loop is switched to the second abrasive slurry supply pipe loop 562 to supply the new batch of abrasive slurry mixture to the CMP apparatus 52, as described in operation 122. In operation 124, the engineer enhances the online monitoring data and checks whether the online status of the new batch of abrasive slurry mixture in the second abrasive slurry supply pipe loop 562 is normal. If the online status is normal, the second abrasive slurry supply pipe loop 562 remains operational to supply the new batch of abrasive slurry mixture to the CMP apparatus 52, and the abrasive slurry freshness alert ends, as described in operation 114. If the online status is abnormal, the method proceeds to operation 108 again.

[0061] Method 100 is merely an example and is not intended to limit the present disclosure beyond what is expressly recited in the claims. Additional operations may be provided before, during, and after method 100, and some of the described operations may be replaced, eliminated, or freely moved for additional embodiments of the method.

[0062] As described, when the polishing liquid is repeatedly used, the abrasive in the polishing liquid will aggregate and grow larger. Therefore, the freshness of the polishing liquid can be determined by checking the size of its abrasive. The larger the abrasive size, the less fresh the polishing liquid. In some embodiments of the present disclosure, a polishing liquid monitoring device and an on-line polishing liquid monitoring method are provided. The polishing liquid monitoring device is configured to optically detect the particle size of polishing particles and other solid particles in the polishing liquid, and thus particle aggregation can be detected at an early stage. In some embodiments of the present disclosure, a CMP system is also provided. The CMP system includes two or more polishing liquid supply units and their corresponding polishing liquid supply pipe circuits, and the polishing liquid monitoring device is installed between and in communication with these polishing liquid supply pipe circuits. After oversized polishing particles or residues are detected by the polishing liquid monitoring device, the polishing liquid supply pipe circuit in which the oversized polishing particles or residues are detected is disconnected from the CMP device, so that the non-fresh polishing liquid is not delivered to the CMP device, and another polishing liquid supply pipe circuit is connected to the CMP device to supply fresh polishing liquid to the CMP device. The polishing liquid monitoring method uses an optical detection mechanism to on-line check the quality of the polishing liquid by measuring the size of the polishing particles. The optical detection mechanism is a non-destructive mechanism, which can check the freshness of the polishing liquid in real time, and thus can improve the yield of the CMP operation.

[0063] In some embodiments, a polishing liquid monitoring device includes a polishing liquid metering unit, a plurality of light sources, and at least one optical detector. The polishing liquid metering unit is configured to hold the polishing liquid. The light sources are configured to emit light beams onto the polishing liquid in the polishing liquid metering unit. The light sources include a first light source configured to emit a first light beam having a first wavelength and a second light source configured to emit a second light beam having a second wavelength longer than the first wavelength. The at least one optical detector is configured to detect the intensity of the light beams scattered by the polishing particles in the polishing liquid.

[0064] In some embodiments, a chemical mechanical polishing (CMP) system includes at least one CMP device, a first abrasive slurry supply unit, a second abrasive slurry supply unit, a first abrasive slurry supply pipe circuit, a second abrasive slurry supply pipe circuit, and an abrasive slurry monitoring device. The first abrasive slurry supply unit and the second abrasive slurry supply unit are configured to supply abrasive slurry to the CMP device. The first abrasive slurry supply pipe circuit is connected to the first abrasive slurry supply unit and the at least one CMP device. The second abrasive slurry supply pipe circuit is connected to the second abrasive slurry supply unit and the at least one CMP device. The abrasive slurry monitoring device is connected to the first abrasive slurry supply pipe circuit and the second abrasive slurry supply pipe circuit and is configured to monitor the quality of the abrasive slurry.

[0065] In some embodiments, a method for on-line monitoring of abrasive slurry includes the following operations. Conduct the abrasive slurry from a first abrasive slurry supply pipe circuit to an abrasive slurry metering unit. Irradiate the abrasive slurry contained in the abrasive slurry metering unit with a light beam. Detect the intensity of the light beam scattered by abrasive particles of the abrasive slurry. Obtain an estimated size of the abrasive particles in the abrasive slurry based on the intensity of the light beam scattered by the abrasive particles of the abrasive slurry.

[0066] The structures of several embodiments have been outlined above so that those skilled in the art can better understand aspects of the present disclosure. Those skilled in the art should understand that they can readily use the present disclosure as a basis for designing or modifying other programs and structures to achieve the same purposes as the embodiments introduced herein and / or realize the same advantages as the embodiments introduced herein. Those skilled in the art should also be aware that these equivalent constructs should not depart from the spirit and scope of the present disclosure, and that various changes, substitutions, and alterations can be made to this document without departing from the spirit and scope of the present disclosure.

[0067] Symbol Explanation

[0068] 1: Abrasive slurry monitoring device

[0069] 2: Abrasive slurry monitoring device

[0070] 2': Abrasive slurry monitoring device

[0071] 2dp: Distance

[0072] 3: Abrasive slurry monitoring device

[0073] 4: Abrasive slurry monitoring device

[0074] 5: Abrasive slurry monitoring device

[0075] 12: Abrasive slurry metering unit

[0076] 14: Light source

[0077] 16: Optical detector

[0078] 16S: Electrical signal

[0079] 16W: Optical sensing window

[0080] 18: Black box

[0081] 20: Abrasive slurry

[0082] 20A: Inlet

[0083] 20B: Outlet

[0084] 20P: Abrasive particles

[0085] 32: Light interceptor

[0086] 34: Optical lens

[0087] 50: Chemical mechanical polishing (CMP) system

[0088] 52: CMP equipment

[0089] 58: Controller

[0090] 60: Abrasive slurry monitoring device

[0091] 64: Mixing tank

[0092] 66: Pump

[0093] 68: Valve manifold box (VMB)

[0094] 100: Method

[0095] 102: Operation

[0096] 104: Operation

[0097] 106: Operation

[0098] 108: Operation

[0099] 110: Operation

[0100] 112: Operation

[0101] 114: Operation

[0102] 116: Operation

[0103] 118: Operation

[0104] 120: Operation

[0105] 121: First side

[0106] 122: Second side / Operation

[0107] 123: Third side

[0108] 124: Fourth side / Operation

[0109] 541: First polishing liquid supply unit

[0110] 542: Second polishing liquid supply unit

[0111] 561: First polishing liquid supply pipe circuit

[0112] 562: Second polishing liquid supply pipe circuit

[0113] 621: First barrel

[0114] 622: Second barrel

[0115] 701: First valve

[0116] 702: Second valve

[0117] d: Diameter

[0118] dp: Diameter

[0119] F: Flowmeter

[0120] L: Distance

[0121] LB: Light beam

[0122] LB': Scattered light beam

[0123] SP: Light spot

[0124] Z: Diameter.

Claims

1. A polishing liquid monitoring device, comprising: A polishing liquid metering unit configured to hold a polishing liquid; A plurality of light sources configured to emit light beams onto the polishing liquid in the polishing liquid metering unit, wherein the light sources include a first light source configured to emit a first light beam having a first wavelength and a second light source configured to emit a second light beam having a second wavelength the same as the first wavelength; At least one light interceptor placed between the light source and the polishing liquid metering unit, wherein the number of the light interceptors is less than the number of the light sources; and At least one optical detector configured to detect the intensity of the light beam scattered by the abrasive particles in the polishing liquid, Wherein the first light source emits the first light beam through the at least one light interceptor to the polishing liquid metering unit, and the second light source emits the second light beam directly to the polishing liquid metering unit.

2. The polishing liquid monitoring device according to claim 1, wherein the polishing liquid metering unit is connected to a polishing liquid supply pipe loop of a chemical mechanical polishing (CMP) system.

3. The polishing liquid monitoring device according to claim 1, wherein an inlet of the polishing liquid is placed on a first side of the polishing liquid metering unit, and an outlet of the polishing liquid is placed on a second side of the polishing liquid metering unit, wherein the first side and the second side are opposite to each other.

4. The polishing liquid monitoring device according to claim 3, wherein the light source is placed adjacent to a third side of the polishing liquid metering unit, and the at least one optical detector is placed adjacent to a fourth side of the polishing liquid metering unit, and wherein the third side and the fourth side are opposite to each other.

5. The polishing liquid monitoring device according to claim 1, wherein the at least one light interceptor modifies a pulse duration of the first light beam.

6. The polishing liquid monitoring device according to claim 1, wherein the first light source has a first pulse duration and the second light source has a second pulse duration.

7. The polishing liquid monitoring device according to claim 1, further comprising at least one optical lens placed between the at least one light source and the polishing liquid metering unit and configured to modify a size of a light spot of the light beam irradiated on the polishing liquid.

8. A chemical mechanical polishing (CMP) system, comprising: At least one CMP device; A first polishing liquid supply unit and a second polishing liquid supply unit that supply a polishing liquid to the at least one CMP device; A first polishing liquid supply pipe loop and a second polishing liquid supply pipe loop, the first polishing liquid supply pipe loop being connected to the first polishing liquid supply unit and the at least one CMP device, the second polishing liquid supply pipe loop being connected to the second polishing liquid supply unit and the at least one CMP device; And A polishing liquid monitoring device connected to the first polishing liquid supply pipe loop and the second polishing liquid supply pipe loop and configured to monitor the quality of the polishing liquid, wherein the polishing liquid monitoring device includes: A slurry metering unit, which is connected to the first slurry supply pipe circuit and the second slurry supply pipe circuit and is configured to accommodate the slurry; A first light source and a second light source; and A light interceptor, which is placed between the first light source and the slurry metering unit, wherein the first light source emits a first light beam through the light interceptor to the slurry metering unit, and the second light source emits the second light beam directly to the slurry metering unit.

9. The CMP system according to claim 8, wherein the slurry monitoring device comprises: At least one optical detector, which is configured to detect the intensity of the first light beam and the intensity of the second light beam scattered by the abrasive particles in the slurry.

10. The CMP system according to claim 8, which further comprises a first valve connected between the slurry monitoring device and the first slurry supply pipe circuit and a second valve connected between the slurry monitoring device and the second slurry supply pipe circuit to switch the slurry from the first slurry supply pipe circuit or the second slurry supply pipe circuit to the slurry monitoring device.

11. The CMP system according to claim 10, wherein the slurry metering unit is connected to the slurry return pipelines of the first slurry supply pipe circuit and the second slurry supply pipe circuit.

12. The CMP system according to claim 10, which further comprises a controller connected to the slurry monitoring device and configured to control the slurry monitoring device.

13. A method for on-line monitoring of slurry, which comprises: Conducting the slurry from a first slurry supply pipe circuit to a slurry metering unit; Irradiating the slurry accommodated in the slurry metering unit with a first light beam passing through a light interceptor; Directly irradiating the slurry accommodated in the slurry metering unit with a second light beam; Detecting the intensity of the first light beam and the intensity of the second light beam scattered by the abrasive particles of the slurry; and Obtaining an estimated size of the abrasive particles in the slurry based on the intensities of the first light beam and the second light beam scattered by the abrasive particles of the slurry.

14. The method according to claim 13, which further comprises modifying the pulse duration of the first light beam irradiated on the slurry by the light interceptor.

15. The method according to claim 14, wherein the pulse duration is modified based on a reference size of the abrasive particles.

16. The method according to claim 13, which further comprises modifying the size of the light spot of the light beam irradiated on the slurry by an optical lens.

17. The method according to claim 13, which further comprises sending a notification when the estimated size of the abrasive particles is greater than the reference size of the abrasive particles.

18. The method according to claim 13, which further comprises: Closing the supply of the first slurry supply pipe circuit when the result of the on-line monitoring of the slurry is abnormal; and Switching the supply of the first slurry supply pipe circuit to a second slurry supply pipe circuit.

19. The method according to claim 13, wherein the first light beam and the second light beam have the same wavelength.

20. The method according to claim 19, wherein the intensities of the light beams of different wavelengths scattered by the abrasive particles of the abrasive liquid are detected by a plurality of optical detectors.

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