Intelligent polishing liquid replenishment system

Abstract

This invention provides an intelligent grinding slurry replenishment system, including a mixing device, a supply tank, and a control unit. The mixing device is used to mix and prepare the required amount of grinding slurry and is equipped with a delivery pipe to output the grinding slurry. The supply tank is equipped with a level sensor, and the delivery pipe outputs the grinding slurry into the supply tank. The level sensor is responsible for measuring the level in the supply tank and outputting percentage level information. The supply tank is also equipped with an output pipe to output the grinding slurry. The control unit is electrically connected to the level sensor to receive the level information and controls the mixing device to prepare the grinding slurry based on the changes in the amount of slurry consumed and the required time. Therefore, by replenishing the grinding slurry appropriately according to the usage of the supply tank, the quality of the grinding slurry supply can be maintained to meet the grinding requirements, and the waste of grinding slurry can be avoided, significantly saving production costs. This is an innovative design for intelligent replenishment.

Description

Technical Field

[0001] This utility model relates to the technical field of polishing slurry supply systems, and in particular to an intelligent polishing slurry replenishment system. Background Technology

[0002] In chemical mechanical polishing (CMP) processes in semiconductor manufacturing, polishing slurry is essential in conjunction with polishing equipment. However, before use, the slurry must be mixed thoroughly, including the polishing concentrate, deionized water, and solvent, to achieve the required conditions. Because the chemical components and abrasive particles added to the slurry may deteriorate or precipitate over time, resulting in poor slurry quality when supplied to the machine and affecting the chemical polishing effect. Therefore, polishing supply tanks are generally equipped with a forced drainage mechanism to remove slurry that has been stagnant for too long. This has led to the industry term "slurry freshness." Using freshly mixed slurry results in better polishing quality, but the longer the slurry remains stagnant, the lower its freshness becomes. The freshness value of freshly mixed slurry is 1, gradually decreasing over time, ranging from 0 to 1. In recent years, semiconductor manufacturing processes have become smaller and more precise, which in turn places greater demands on the freshness of polishing slurries. This is why forced discharge mechanisms exist. However, the current method for maintaining the freshness of polishing slurries is to discharge them immediately when the set time is reached, which inevitably leads to misjudgments and waste of polishing slurries.

[0003] like Figure 1 The diagram shows a schematic of a grinding slurry supply tank used in the prior art. The grinding slurry supply tank 10 has a replenishment pipe 11 at the top and a supply pipe 12 at the bottom. The replenishment pipe 11 connects to a grinding slurry mixing device to deliver the mixed grinding slurry into the supply tank 10, and then the supply pipe 12 delivers the grinding slurry to the corresponding grinding machine as needed. The supply pipe 12 is also connected to a forced drainage pipe 14. When the grinding slurry in the supply tank 10 has been stagnant for too long, the valve of the forced drainage pipe 14 will be opened to drain some of the grinding slurry, and then freshly mixed grinding slurry will be added to maintain the freshness of the grinding slurry. Several capacitive level sensors 131, 132, 133, 134, and 135 are installed at different heights on the outer wall of the supply tank 10, representing five positions: [highest, high, medium, low, lowest]. When the liquid inside the supply tank 10 reaches the corresponding position, the corresponding capacitive level sensor sends a signal to inform the system of the current liquid level status.

[0004] However, this type of supply tank 10 is prone to significant waste during the grinding fluid replenishment and forced drainage mechanisms. Because the internal liquid level of the supply tank 10 cannot be accurately determined, the replenishment mechanism is as follows: when the liquid level in the supply tank 10 is below the [medium] position, a large amount of grinding fluid is immediately prepared and supplied at once. After mixing, it is then fed into the supply tank 10 to directly replenish it to the [high] or [maximum] position. However, if the supply tank 10 does not reach the set value within a certain period, for example, if the liquid level remains above the [medium] position for 5 hours, a forced drainage mechanism is activated. The valve connected to the forced drainage pipe 14 is opened directly to drain the grinding fluid that may have settled at the bottom of the supply tank 10 until the liquid level drops to the [medium] position, at which point drainage stops. Then, a large amount of freshly mixed grinding fluid is injected according to the above replenishment mechanism to bring the liquid level in the supply tank 10 back to the [high] or [maximum] position.

[0005] Under the above operating mechanism, regardless of the speed of usage, once the liquid level is below the [medium] position, a large amount of grinding fluid needs to be prepared at once to replenish the supply tank 10 so that the liquid level reaches the [high] or [maximum] position. When the grinding fluid is used rapidly for a long time, this mechanism has no problem. However, if the consumption is frequently or continuously lower than the set time, a large amount of grinding fluid will be continuously discharged and a large amount of grinding fluid will be prepared and injected again. This will cause waste of grinding fluid. Since the unit price of grinding fluid is high, this waste will also increase production costs. Therefore, the inventors have considered designing an intelligent grinding fluid replenishment system. Utility Model Content

[0006] The main purpose of this invention is to provide an intelligent grinding slurry replenishment system. It mainly uses a control unit to accurately obtain the liquid level from the grinding slurry supply tank, and then controls the mixing equipment to mix and adjust the appropriate amount of liquid. Therefore, it can accurately supply the appropriate amount of grinding slurry to the supply tank according to different usage and freshness of grinding slurry. In addition to maintaining the best supply quality of grinding slurry and meeting the required grinding requirements, it can also avoid waste of grinding slurry and save production costs.

[0007] To achieve the above objectives, the present invention adopts the following technical solution:

[0008] This utility model relates to an intelligent grinding slurry replenishment system, comprising: a mixing device, a supply tank, and a control unit. The mixing device can mix the required amount of grinding slurry and has a delivery pipe for outputting the grinding slurry. The supply tank is equipped with a level sensor, and the delivery pipe is connected to the supply tank and outputs the grinding slurry into the supply tank. The level sensor is responsible for measuring the liquid volume in the supply tank and outputting percentage level information. The supply tank is equipped with an output pipe for outputting the grinding slurry. The control unit is electrically connected to the level sensor to receive the level information and monitor changes in liquid volume, and controls the mixing device to adjust the amount of grinding slurry based on the changes in liquid consumption and required time.

[0009] As one of the preferred embodiments, the liquid level sensor is installed in the supply tank. The liquid level sensor is a hydrostatic liquid level sensor that can provide percentage information about the liquid level.

[0010] As one of the preferred embodiments, the liquid level sensor is installed on the tank cover of the supply tank. The liquid level sensor is a radar-type liquid level sensor that can provide percentage information of the liquid level.

[0011] As one of the preferred embodiments, this change value is the ratio of the amount of liquid consumed to the time required.

[0012] As one of the preferred embodiments, the control unit calculates the freshness of the grinding fluid, and when the freshness of the grinding fluid is lower than a set value, a forced drainage mechanism is activated.

[0013] As one of the preferred embodiments, the output pipe is connected to a discharge pipe, which is normally closed. The forced discharge mechanism refers to opening the valve of the discharge pipe to allow the grinding fluid in the supply tank to flow out through the discharge pipe, and closing the valve when the liquid level in the supply tank drops to a set value.

[0014] As one of the preferred embodiments, the mixing device is a grinding fluid mixing tank structure.

[0015] Compared to existing technologies, this intelligent grinding slurry replenishment system utilizes a control unit to regulate the mixing equipment and produce an appropriate amount of grinding slurry based on the usage of the supply tank. For example, when the usage is large, a large quantity of grinding slurry can be mixed and prepared at once; when the usage decreases, the amount of grinding slurry mixed can be reduced, avoiding the wasteful practice of forcibly draining slurry after a set time if it is not used. Furthermore, the control unit uses a calculation formula to determine the freshness of the grinding slurry and decides the timing of forced drainage based on the freshness value, thus preventing waste. Conventional structures can only employ a timed forced drainage mechanism, which easily leads to significant waste of grinding slurry. Moreover, if the control unit detects abnormal usage, such as excessively rapid or insufficient slurry consumption in the supply tank, it can issue an alarm to inform the user and resolve the issue, providing an intelligent replenishment system. Attached Figure Description

[0016] Figure 1 A schematic diagram of a grinding fluid supply tank used in the prior art;

[0017] Figure 2 This is a structural diagram of the present utility model;

[0018] Figure 3 This is a schematic diagram of the mixing device of this utility model;

[0019] Figure 4 This is a schematic diagram of the supply tank of this utility model;

[0020] Figure 5 A graph showing the relationship between the amount of grinding slurry consumed and time;

[0021] Figure 6 A schematic diagram showing the use of another liquid level sensor in the supply tank of this utility model;

[0022] Figure 7 A schematic diagram showing an alternative structure for mounting a liquid level sensor in the supply tank of this utility model;

[0023] Figure 8 This is a schematic diagram of another structure for installing a liquid level sensor in the supply tank of this utility model.

[0024] Explanation of reference numerals in the attached figures:

[0025] 10: Supply tank;

[0026] 11: Infusion tubing;

[0027] 12: Liquid supply pipe;

[0028] 131, 132, 133, 134, 135: Capacitive liquid level sensors;

[0029] 14: Forced exhaust pipe;

[0030] 30: Mixing equipment;

[0031] 31: Infusion tube;

[0032] 32: Mixing tank;

[0033] 33, 34, 35: Raw material supply pipes;

[0034] 36: Agitator pump;

[0035] 40: Supply tank;

[0036] 41: Liquid level sensor;

[0037] 41A: Liquid level sensor;

[0038] 42: Output tube;

[0039] 43: Discharge pipe;

[0040] 45: Slot cover;

[0041] 50: Control unit;

[0042] 60: Support base;

[0043] 70: Bracket;

[0044] :angle. Detailed Implementation

[0045] The technical solution of this utility model will now be clearly and completely described in conjunction with specific embodiments and accompanying drawings. It should be noted that when a component is referred to as being "mounted to or fixed to" another component, it means that it can be directly on the other component or that an intermediate component may be present. When a component is considered to be "connected to" another component, it means that it can be directly connected to the other component or that an intermediate component may be present simultaneously. In the illustrated embodiments, directions such as up, down, left, right, front, and back are relative and are used to explain the relative structure and movement of different components in this invention. These representations are appropriate when the components are in the positions shown in the figures. However, if the description of the component positions changes, then these representations are also considered to change accordingly.

[0046] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0047] like Figure 2The diagram shown is an architectural representation of this utility model. The intelligent grinding slurry replenishment system of this utility model includes a mixing device 30, a supply tank 40, and a control unit 50. The mixing device 30 is responsible for mixing and adjusting the required amount of grinding slurry and is equipped with a delivery pipe 31 to output the grinding slurry. The supply tank 40 is equipped with a level sensor 41. The delivery pipe 31 is connected to the supply tank 40 and outputs the grinding slurry into the supply tank 40. The level sensor 41 is responsible for measuring the level in the supply tank 40 and can output percentage level information. The supply tank 40 is also equipped with an output pipe 42 for outputting the grinding slurry to the grinding machine. The control unit 50 is an industrial computer or a programmable controller, electrically... The liquid level sensor 41 is connected to receive the provided liquid level information and monitor the changes in liquid volume. Based on the changes in liquid consumption and time, the mixing device 30 is controlled to adjust the set amount of grinding liquid. Then, the grinding liquid is delivered to the supply tank 40 through the delivery pipe 31 in a timely manner. Therefore, this utility model can replenish the grinding liquid to the supply tank 40 in an appropriate amount according to the consumption of the supply tank 40. In addition to maintaining the best supply quality of the grinding liquid, that is, maintaining the freshness of the grinding liquid and meeting the high-quality grinding requirements, it can also avoid the waste of adding too much grinding liquid at one time, which would cause it to be discharged before the predetermined time is used up. This greatly saves production costs and is an innovative design for intelligent liquid replenishment.

[0048] Next, a detailed explanation of the structure of each component will be given:

[0049] The mixing device 30 is a grinding fluid mixing tank structure, which can be of various types. This utility model only describes one type, such as... Figure 3 As shown, the mixing device 30 includes a mixing tank 32 and several raw material supply pipes 33, 34, and 35. The raw material supply pipes include concentrated grinding slurry supply pipes, deionized water supply pipes, and solvent supply pipes. An inclined stirring pump 36 is installed inside the mixing tank 32. In this embodiment, the stirring pump 36 is a magnetic levitation pump, which provides good stirring effect to the mixing tank 32. A delivery pipe 31 is provided at the bottom of the mixing tank 32 to output the mixed grinding slurry. After the control unit 50 controls the mixing device 30 to output the required amount of grinding slurry, other control systems operate to inject an appropriate amount of concentrated grinding slurry, deionized water, and solvent into the mixing tank 32. The mixture is then uniformly stirred and mixed by the stirring pump 36, and finally transported to the supply tank 40 via the delivery pipe 31 and other pumps.

[0050] The supply tank 40 is used to temporarily store a large amount of mixed grinding fluid for subsequent distribution to the corresponding grinding machine via the distribution valve box. For example... Figure 4As shown, in this embodiment, a liquid level sensor 41 is provided in the supply tank 40. The liquid level sensor 41 in this embodiment is a hydrostatic liquid level sensor, which is a type of analog liquid level sensor. It can provide percentage liquid level information, thus providing accurate liquid level information on the liquid volume in the supply tank 40, allowing the control unit 50 to clearly obtain the change value of time and liquid consumption. In this embodiment, the change value is the ratio of liquid consumption to the required time. In addition, the infusion pipe 31 is connected to the top of the supply tank 40 to inject the mixed grinding slurry in a timely manner. The bottom of the supply tank 40 is also provided with an output pipe 42 for conveying the grinding slurry to the grinding machine. The output pipe 42 is also connected to a discharge pipe 43. Normally, the discharge pipe 43 is in a closed state. When the grinding slurry stagnates for too long, that is, when the freshness of the grinding slurry is lower than the set value, the discharge pipe 43 will be opened first to discharge some grinding slurry, and then an appropriate amount of freshly mixed grinding slurry will be injected to improve the freshness of the grinding slurry and maintain the quality of the grinding slurry.

[0051] The control unit 50 is an industrial computer or programmable controller. It provides accurate information on the liquid level changes in the supply tank 40 via the liquid level sensor 41. Combined with the amount of grinding fluid consumed within a set time, it can determine and estimate the amount of grinding fluid to be used in the grinding machine. This allows for dynamic adjustment of the mixing or replenishment frequency of the mixing equipment 30 to maintain the freshness and quality of the grinding fluid, thus avoiding waste and achieving the goal of intelligent replenishment.

[0052] The following figures illustrate three operating modes of this invention to explain the operation of the intelligent fluid replacement system, such as... Figure 5 To generate a graph showing the distribution of slurry consumption over time, the control unit 50 obtains the slurry level from the level sensor 41. The highest slurry level minus the current slurry level equals the slurry consumption. This graph is then plotted based on the slurry consumption and the required time. For different slurry levels, two different slurry consumption and required time data points can be extracted, for example, (x1, y1) and (x2, y2). The slope m can then be calculated. θ is an angle. Therefore, in this embodiment, the change value is the ratio of the consumed liquid volume to the required time, which is the slope m. This system still maintains the requirement to replenish liquid when the liquid level in the supply tank 40 is below 50%. The difference is that the design of this utility model can intelligently adjust the replenishment amount or mixing amount according to the liquid consumption status of the previous stage, that is, adjust the replenishment amount or mixing amount according to the change value of the consumed liquid volume and the required time.

[0053] Before replenishing the liquid, for example, in scenario one, the slope of the liquid level is obtained between 60% and 55%. If the slope is less than 0.5 (θ < 22.5°), it indicates that the liquid consumption is decreasing. The control unit 50 controls the mixing device 30 to mix and adjust only 1 / 2 of the set amount (e.g., mix 40 liters) before replenishing it into the supply tank 40 to save on raw material loss. In scenario two, the slope of the liquid level is obtained between 60% and 55%. If 1 > slope > 0.5 (e.g., 45° > θ > 22.5°), it indicates that the liquid consumption is within the normal range. The control unit 50 controls the mixing device 30 to mix and adjust the set amount (e.g., mix 80 liters). In scenario three, when the liquid level reaches 60% to 55%, the slope is calculated first. If the slope is greater than 1 (θ > 45°), it indicates that the liquid consumption is increasing rapidly. The control unit 50 can then control the mixing device 30 to adjust the mixing to the set amount (e.g., 80 liters). When the liquid level drops to 50%, it is immediately replenished to ensure a continuous and large supply. Of course, the above scenarios, slope values, and mixing amounts are for reference only; users must design their own solutions based on their specific needs. Furthermore, the control unit 50 can also set different reaction mechanisms for different scenarios. For example, if the system remains in scenario one for an extended period, it may indicate a machine malfunction and stoppage. A warning can be issued by cross-comparison to notify the operator. Alternatively, if the slope is too high, it may indicate a pipeline leak, and the operator can be alerted accordingly. This invention, through its intelligent liquid replenishment operation, not only maintains the optimal supply quality of the grinding slurry to meet the required grinding requirements but also avoids waste of the grinding slurry, saving production costs.

[0054] In addition, this invention has a unique feature: the control unit 50 activates the forced discharge mechanism by calculating the [freshness of the grinding slurry]. The forced discharge mechanism refers to opening the valve of the discharge pipe 43, allowing the grinding slurry in the supply tank 40 to flow out through the discharge pipe 43. The valve is closed when the liquid level in the supply tank 40 drops to a set value, which in this embodiment is 50% of the liquid level. Afterward, the replenishment system injects an appropriate amount of the mixed grinding slurry to improve the freshness of the grinding slurry and ensure its quality.

[0055] This utility model provides a formula for calculating the freshness of grinding fluid, as shown below. This part mainly calculates the freshness F of the grinding fluid in the supply tank 40.

[0056]

[0057] Where K = aging factor, a constant, is a set value based on the characteristics of the polishing fluid used, 0 <K<1。

[0058] t is the time unit for setting the interval (t=1,2,3……).

[0059] The freshness of the grinding fluid in the tank (i.e., the freshness F after the previous calculation), 0 < <1.

[0060] To ensure the freshness of the freshly mixed grinding solution, =1.

[0061] The weight of the grinding fluid mixed in each cycle by the mixing equipment is 30.

[0062] The total weight of the new / old grinding fluid supplied to tank 40.

[0063] As shown in the formula above, the K value is multiplied each time the measurement is taken. Therefore, the freshness F of the grinding slurry decreases with time, but the freshness F will increase again after adding new mixed grinding slurry. Experiments have shown that the optimal value for the freshness of the grinding slurry is: In this invention, the control unit 50 calculates the freshness F of the grinding slurry in the supply tank 40 at set intervals. When the freshness F drops to the set value, it means that the quality of the grinding slurry in the supply tank 40 has decreased. At this time, the forced discharge mechanism is activated, and the grinding slurry that has been retained for a long time is discharged through the discharge pipe 43. After the liquid level drops to 50%, according to the intelligent analysis mode mentioned above, an appropriate amount of freshly mixed grinding slurry is added based on the amount of liquid consumed in the previous stage. Instead of discharging a large amount of grinding slurry after a fixed time as in the existing technology, this invention can effectively avoid the waste of grinding slurry.

[0064] like Figure 6 The diagram shows a different liquid level sensor used in the supply tank of this utility model. In this embodiment, the supply tank 40 has a liquid level sensor 41A on the tank cover 45. The liquid level sensor 41A is a radar liquid level sensor, a non-contact liquid level gauge. This radar liquid level sensor has a downward-facing sensing head (which is not visible in the bottom view). The radar liquid level sensor 41A is installed on the tank cover 45 with the sensing head facing the tank cover 45. The radar wave emitted by the radar liquid level sensor penetrates the tank cover 45 to measure the liquid level in the supply tank 40. The tank cover 45 is made of plastic sheet and is less than 2 cm thick.

[0065] The operating principle of a radar level gauge is to use a sensor head to emit radar waves. These radar waves are part of the electromagnetic spectrum and have low dielectric loss on certain types of materials (such as plastics, glass, and fiberglass). This means that the radar waves can propagate and pass through these materials. Finally, the radar waves are reflected only when they reach the liquid surface in the tank. The sensor head receives the reflected radar wave signal, and through comparison and calculation, the percentage of the liquid level in the supply tank 40 can be accurately calculated. This helps to more accurately determine the liquid level value in the supply tank 40. Because it is a non-contact measurement, it avoids the sensor coming into contact with the grinding fluid and diluting impurities, thus affecting the quality of the grinding fluid, or the sensor being damaged by contact with the acid or alkaline properties of the liquid or by evaporation.

[0066] To ensure that the radar-type liquid level sensor is more stably mounted on the tank cover 45, this utility model also provides a support 60 with a through channel. The support 60 is set on the tank cover 45 for the radar-type liquid level sensor to be mounted on the support 60. The sensing head emits radar waves to the tank cover 45 through the channel to measure the liquid level in the supply tank 40.

[0067] like Figure 7 The diagram shows a different structure for installing a liquid level sensor in the supply tank of this invention. This invention also includes a bracket 70, which extends horizontally above the tank cover 45. A radar-type liquid level sensor 41A is installed at one end of the bracket 70, and the other end of the bracket 70 is fixed to the machine base. In this embodiment, the other end of the bracket 70 is fixed to the side wall 81 of the machine base, so that the radar-type liquid level sensor's sensing head faces the tank cover 45. The radar-type liquid level sensor can be in contact or non-contact configuration and is located on or above the tank cover 45.

[0068] like Figure 8 The diagram shows another configuration for installing a liquid level sensor in the supply tank of this invention. In this embodiment, a bracket 70 is still provided, but the bracket 70 extends vertically above the tank cover 45. A radar-type liquid level sensor 41A is installed at one end (bottom) of the bracket 70, and the other end (top) of the bracket 70 is fixed to the machine base. In this embodiment, the top of the bracket 70 is fixed to the top wall of the machine base, so that the radar-type liquid level sensor's sensing head faces the tank cover 45. The radar-type liquid level sensor can be either contact or non-contact and is located on or above the tank cover 45. Therefore, the liquid level sensor used in the supply tank of this invention must be able to provide percentage liquid level information and can be installed inside or outside the supply tank.

[0069] The above description is merely a preferred embodiment of the present utility model and is not intended to limit the scope of the embodiments of the present utility model. All equivalent variations and modifications made within the scope of the claims of the present utility model are covered by the patent scope of the present utility model.

Claims

1. An intelligent polishing liquid replenishment system, characterized by, include: A mixing device for mixing and preparing the required amount of grinding fluid, and equipped with a delivery pipe to output the grinding fluid; A supply tank equipped with a level sensor; a delivery pipe connected to the supply tank and supplying grinding fluid into the supply tank; the level sensor measures the level in the supply tank and outputs a percentage level information; the supply tank is equipped with an output pipe for supplying grinding fluid to the grinding machine; and A control unit is electrically connected to the liquid level sensor to receive liquid level information and monitor changes in liquid volume, and controls the mixing device to prepare the corresponding amount of grinding slurry based on the changes in liquid consumption and required time.

2. The intelligent polishing liquid replenishing system according to claim 1, wherein, The liquid level sensor is installed in the supply tank. The liquid level sensor is a hydrostatic liquid level sensor that can provide percentage liquid level information.

3. The intelligent polishing liquid replenishing system according to claim 1, wherein, The liquid level sensor is installed on the tank cover of the supply tank. The liquid level sensor is a radar-type liquid level sensor that can provide a percentage liquid level value.

4. The intelligent polishing liquid replenishing system according to claim 1, wherein, The change value is the ratio of the amount of liquid consumed to the time required.

5. The intelligent polishing liquid replenishing system of claim 1, wherein, The control unit is used to calculate the freshness of the grinding fluid, and when the freshness of the grinding fluid is lower than a set value, a forced drainage mechanism is activated.

6. The intelligent polishing liquid replenishing system according to claim 5, wherein, The output pipe is connected to a discharge pipe, which is normally closed. The forced discharge mechanism refers to opening the valve of the discharge pipe to allow the grinding fluid in the supply tank to flow out through the discharge pipe, and closing the valve when the liquid level in the supply tank drops to a set value.

7. The intelligent polishing liquid replenishing system of claim 1, wherein, The mixing device is a grinding fluid mixing tank structure.

Images