A zeta potential monitoring and regulating device for cmp slurry

Abstract

The utility model discloses a kind of Zeta potential monitoring control devices for CMP polishing liquid, including liquid supply pool, further include several temporary storage pool, the liquid supply pool is connected temporary storage pool by first conveying device, two feeding devices are connected on the temporary storage pool, monitoring device for monitoring the Zeta potential of polishing liquid in temporary storage pool is also connected on the temporary storage pool, stirring device is provided in the temporary storage pool. Compared with prior art, the two feeding devices of the utility model send material into temporary storage pool, to dynamically adjust the Zeta potential of polishing liquid, and setting stirring device can stir the material in temporary storage pool evenly, can effectively avoid the Zeta potential of polishing liquid in liquid supply system during CMP polishing process changes greatly, enhance the stability of Zeta potential.

Description

Technical Field

[0001] This utility model relates to the field of chemical mechanical polishing technology, and in particular to a Zeta potential monitoring and control device for CMP polishing slurry. Background Technology

[0002] In semiconductor manufacturing, chemical mechanical polishing (CMP) is a key process for wafer surface planarization, and the zeta potential plays a crucial role in the stability control of CMP slurry, the optimization of the polishing process, and the assurance of surface quality. The zeta potential affects the electrostatic repulsion of the polishing particles, preventing agglomeration and sedimentation, ensuring uniform dispersion of the slurry, thereby reducing wafer scratches and extending slurry life. Furthermore, precise control of the zeta potential can optimize the interaction between particles and the wafer surface, balancing mechanical removal and chemical etching, improving material removal efficiency, and reducing defect rates.

[0003] However, fluctuations in the zeta potential in traditional CMP slurry supply systems primarily stem from the instability of solution environmental parameters during slurry recycling. For example, oxidants and pH adjusters in the slurry are continuously consumed during the grinding reaction, while dissolved CO2 in the air forms carbonate ions, causing pH shifts. The zeta potential exhibits a strongly non-linear relationship with pH; even small changes can trigger significant fluctuations. Grinding byproducts (such as copper and tungsten ions) dissolve into the slurry, compressing the double layer thickness of the particles and weakening electrostatic repulsion. Additive decomposition or cleaning residues (such as NH4⁺) also introduce interfering ions, neutralizing the surface charge of the particles. The coupled effect of these factors makes it difficult for traditional slurry supply systems to maintain a stable zeta potential, ultimately affecting the zeta potential of the slurry and causing significant deviations from the standard value.

[0004] Therefore, there is an urgent need for a zeta potential monitoring and control device for CMP polishing slurries to solve the above problems. Utility Model Content

[0005] The main purpose of this invention is to provide a Zeta potential monitoring and control device for CMP grinding slurry. Two feeding devices feed materials into a temporary storage tank, thereby dynamically adjusting the Zeta potential of the grinding slurry. A stirring device is also provided to stir the materials in the temporary storage tank evenly, which can effectively avoid large changes in the Zeta potential of the grinding slurry in the supply system during the CMP grinding process and enhance the stability of the Zeta potential.

[0006] To achieve the above objectives, the technical solution adopted by this utility model is as follows:

[0007] A zeta potential monitoring and control device for CMP polishing slurry includes a supply tank and several temporary storage tanks. The supply tank is connected to the temporary storage tanks via a first conveying device. Two feeding devices are connected to the temporary storage tanks. A monitoring device for monitoring the zeta potential of the polishing slurry in the temporary storage tanks is also connected to the temporary storage tanks. A stirring device is provided in the temporary storage tanks.

[0008] Furthermore, the monitoring device is an electrophoresis detector, and the detection end of the electrophoresis detector is inserted into the temporary storage tank.

[0009] Furthermore, the feeding device includes a storage tank and a metering pump. The inlet of the metering pump is connected to the storage tank via a pipe, and the outlet of the metering pump is connected to a temporary storage tank via a pipe.

[0010] Furthermore, the stirring device includes a stirring rod located within a temporary storage tank, and a motor is fixedly mounted at the bottom of the temporary storage tank. The power output end of the motor is fixedly connected to the stirring rod.

[0011] Furthermore, the first conveying device includes a first water pump, the inlet of the first water pump is connected to a supply tank via a pipe, and the outlet of the first water pump is connected to a temporary storage tank via a pipe.

[0012] Furthermore, it also includes a second conveying device.

[0013] Furthermore, the second conveying device includes a second water pump, the inlet of which is connected to a temporary storage tank via a pipe.

[0014] Compared with the prior art, the present invention has the following beneficial effects:

[0015] This invention uses two feeding devices to feed materials into a temporary storage tank, thereby dynamically adjusting the Zeta potential of the grinding slurry. In addition, a stirring device is set up to stir the materials in the temporary storage tank evenly, which can effectively avoid large changes in the Zeta potential of the grinding slurry in the supply system during the CMP grinding process and enhance the stability of the Zeta potential.

[0016] The monitoring device of this invention can detect the Zeta potential of the grinding fluid in the temporary storage tank in real time, so that personnel can adjust the Zeta potential of the grinding fluid.

[0017] The metering pump of this invention can quantitatively add the corresponding materials into the temporary storage tank, thereby ensuring that the materials are neither over- or under-added. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the overall structure of a Zeta potential monitoring and control device for CMP polishing slurry according to the present invention.

[0019] Figure 2 This is a schematic diagram of the temporary storage cell structure of a Zeta potential monitoring and control device for CMP polishing slurry according to the present invention.

[0020] Figure 3 This is a schematic diagram illustrating the usage process of a Zeta potential monitoring and control device for CMP polishing slurry according to this utility model.

[0021] In the diagram: 1. Liquid supply tank; 2. First water pump; 3. Second water pump; 4. Temporary storage tank; 5. Monitoring device; 6. Stirring device; 601. Stirring rod; 602. Motor; 7. Feeding device; 701. Storage tank; 702. Metering pump. Detailed Implementation

[0022] The present invention will now be described in detail with reference to the accompanying drawings.

[0023] In the description of this utility model, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this utility model and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model.

[0024] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this utility model, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0025] In this utility model, unless otherwise explicitly specified and limited, the terms "installation," "connection," "joining," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0026] like Figure 1-3As shown, a zeta potential monitoring and control device for CMP (chemical mechanical polishing) slurry includes a supply tank 1 and several temporary storage tanks 4. The supply tank 1 is connected to the temporary storage tanks 4 through a first conveying device. Two feeding devices 7 are connected to the temporary storage tanks 4. A monitoring device 5 for monitoring the zeta potential of the slurry in the temporary storage tanks 4 is also connected to the temporary storage tanks 4. A stirring device 6 is installed in the temporary storage tanks 4.

[0027] In this embodiment, such as Figure 1 As shown, the monitoring device 5 is an electrophoresis detector. The detection end of the electrophoresis detector is inserted into the temporary storage tank 4. The feeding device 7 includes a storage tank 701 and a metering pump 702. The inlet end of the metering pump 702 is connected to the storage tank 701 through a pipe, and the outlet end of the metering pump 702 is connected to the temporary storage tank 4 through a pipe.

[0028] One feeding device 7 stores polydiallyldimethylammonium chloride in its storage tank 701, while the other feeding device 7 stores sodium polystyrene sulfonate in its storage tank 701. During CMP grinding, the first conveying device transports the grinding liquid from the supply tank 1 to the temporary storage tank 4. At this time, the zeta potential of the grinding liquid in the temporary storage tank 4 is detected by an electrophoresis detector. When the zeta potential of the grinding liquid is lower than the standard value, the corresponding feeding device 7 is controlled to operate, thereby using the metering pump 702 of this feeding device 7 to add the required amount of polydiallyldimethylammonium chloride to the temporary storage tank 4 to increase the zeta potential of the grinding liquid. Conversely, when the zeta potential of the grinding liquid is higher than the standard value, the other feeding device 7 is controlled to operate, thereby using the metering pump 702 of this feeding device 7 to add the required amount of sodium polystyrene sulfonate to the temporary storage tank 4 to decrease the zeta potential of the grinding liquid.

[0029] Among them, such as Figure 1 and Figure 2 As shown, the stirring device 6 includes a stirring rod 601 located in the temporary storage tank 4. A motor 602 is fixed at the bottom of the temporary storage tank 4. The power output end of the motor 602 is fixedly connected to the stirring rod 601. When polydiallyldimethylammonium chloride or sodium polystyrene sulfonate is added to the temporary storage tank 4, the motor 602 can drive the stirring rod 601 to rotate, thereby causing the stirring rod 601 to stir the liquid in the temporary storage tank 4, thus ensuring that the liquid in the temporary storage tank 4 is uniform.

[0030] The first conveying device includes a first water pump 2, the inlet of which is connected to a supply tank 1 via a pipe, and the outlet of which is connected to a temporary storage tank 4 via a pipe. The first water pump 2 can unidirectionally convey the grinding liquid in the supply tank 1 to the temporary storage tank 4. The device also includes a second conveying device, which includes a second water pump 3, the inlet of which is connected to the temporary storage tank 4 via a pipe, and the outlet of which is connected to a production line nozzle. The second water pump 3 can unidirectionally spray the grinding liquid in the temporary storage tank 4 onto the grinding area of ​​the chemical mechanical grinding equipment through the nozzle. Example 1

[0031] During CMP grinding, a temporary storage tank 4 (500L) equipped with an electrophoresis analyzer, polydiallyldimethylammonium chloride (PDMC) and sodium polystyrene sulfonate (PSS) feeding device 7 can be installed at the supply end. The zeta potential of the grinding slurry should be set to deviate from the standard value by less than 5mV, with a maximum tolerance of 10mV. When the target grinding potential is -30mV, if V2 = -34mV (too low), add PDMC to increase it; if V2 = -26mV (too high), add PSS to lower it to -30mV. Repeat the above process to ensure the stability of the zeta potential during grinding. Example 2

[0032] During CMP grinding, two temporary storage tanks 4 (300L + 200L) can be configured at the supply end, each equipped with an electrophoresis analyzer to detect the Zeta potential, and feeding devices 7 for cetyltrimethylammonium bromide and sodium dodecyl sulfate. The Zeta potential of the grinding slurry should be set to deviate from the standard value by less than 3mV, with a maximum tolerance of 7mV. When the target grinding potential is 20mV, if V2 = 18mV (too low), add cetyltrimethylammonium bromide to increase it; if V2 = 22mV (too high), add sodium dodecyl sulfate to lower it to 20mV. Repeat the above process to ensure the stability of the Zeta potential during grinding.

[0033] Working principle: The storage tanks 701 of the two feeding devices 7 store polydiallyl dimethyl ammonium chloride and sodium polystyrene sulfonate, respectively. The first conveying device transports the grinding slurry in the supply tank 1 to the temporary storage tank 4. At this time, the electrophoresis detector detects the Zeta potential of the grinding slurry in the temporary storage tank 4. When the Zeta potential of the grinding slurry is lower than the standard value, the corresponding feeding device 7 is controlled to work, thereby using the metering pump 702 of the feeding device 7 to add the required amount of polydiallyl dimethyl ammonium chloride into the temporary storage tank 4, increasing the Zeta potential of the grinding slurry. When grinding... When the zeta potential of the liquid is higher than the standard value, another feeding device 7 is controlled to work. The metering pump 702 of this feeding device 7 is used to add the required amount of sodium polystyrene sulfonate into the temporary storage tank 4 to reduce the zeta potential of the grinding liquid. The stirring device 6 will also stir the liquid in the temporary storage tank 4 to ensure that the liquid in the temporary storage tank 4 is uniform. This process is repeated to ensure that the zeta potential of the grinding liquid in the temporary storage tank 4 is always comparable to the standard value. This ensures that the second water pump 3 sprays the qualified grinding liquid in the temporary storage tank 4 onto the grinding area of ​​the chemical mechanical grinding equipment through the nozzle.

[0034] The above embodiments are only for illustrating the technical concept and features of this utility model, and are intended to enable those skilled in the art to understand the content of this utility model and implement it accordingly. They should not be construed as limiting the scope of protection of this utility model. All equivalent transformations or modifications made in accordance with the spirit and essence of this utility model should be included within the scope of protection of this utility model.

Claims

1. A zeta potential monitoring and control device for CMP polishing slurry, comprising a slurry supply tank (1), characterized in that: It also includes several temporary storage tanks (4), the liquid supply tank (1) is connected to the temporary storage tank (4) through the first conveying device, the temporary storage tank (4) is connected to two feeding devices (7), the temporary storage tank (4) is also connected to a monitoring device (5) for monitoring the Zeta potential of the grinding liquid in the temporary storage tank (4), and a stirring device (6) is provided in the temporary storage tank (4).

2. The Zeta potential monitoring and control device for CMP polishing slurry according to claim 1, characterized in that: The monitoring device (5) is an electrophoresis detector, and the detection end of the electrophoresis detector is inserted into the temporary storage pool (4).

3. The Zeta potential monitoring and control device for CMP polishing slurry according to claim 1, characterized in that: The feeding device (7) includes a storage tank (701) and a metering pump (702). The inlet of the metering pump (702) is connected to the storage tank (701) through a pipe, and the outlet of the metering pump (702) is connected to the temporary storage tank (4) through a pipe.

4. The Zeta potential monitoring and control device for CMP polishing slurry according to claim 1, characterized in that: The stirring device (6) includes a stirring rod (601) located in a temporary storage tank (4), and a motor (602) is fixed at the bottom of the temporary storage tank (4). The power output end of the motor (602) is fixedly connected to the stirring rod (601).

5. A zeta potential monitoring and control device for CMP polishing slurry according to claim 1, characterized in that: The first conveying device includes a first water pump (2), the inlet end of the first water pump (2) is connected to the supply tank (1) through a pipe, and the outlet end of the first water pump (2) is connected to the temporary storage tank (4) through a pipe.

6. A zeta potential monitoring and control device for CMP polishing slurry according to any one of claims 1-5, characterized in that: It also includes a second conveying device.

7. A zeta potential monitoring and control device for CMP polishing slurry according to claim 6, characterized in that: The second conveying device includes a second water pump (3), the inlet end of which is connected to a temporary storage tank (4) via a pipeline.

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