System for dispensing liquid and method of eliminating bubbles from liquid dispensing system

Abstract

The present disclosure provides a system for dispensing a liquid and a method of eliminating bubbles from a liquid dispensing system. The system includes a filter adapted to filter a liquid and to provide the filtered liquid at a liquid outlet of the filter, and a tank having a liquid inlet coupled to the liquid outlet of the filter via a first tube. The tank includes an upper portion having a first lateral dimension and a lower portion having a second lateral dimension less than the first lateral dimension. The upper portion of the storage tank is located above the liquid inlet of the storage tank.

Description

[0001] This application is a divisional application of the patent application filed on August 28, 2019, with application number 201910803381.X and invention title "System for Dispensing Liquid and Method for Eliminating Air Bubbles from Liquid Dispensing System". Technical Field

[0002] This disclosure relates to a system for dispensing liquids and a method for eliminating air bubbles from the liquid dispensing system. Background Technology

[0003] Semiconductor manufacturing uses various liquids to process semiconductor wafers in order to form integrated circuits (ICs) on these wafers. The liquids used for wafer processing are delivered from supply containers to wafer processing equipment via a liquid dispensing system. Summary of the Invention

[0004] This disclosure relates to a system for distributing liquids, including a filter, a storage tank, and a buffer tank. The filter is suitable for filtering liquids and providing filtered liquid at the filter's liquid outlet. The storage tank includes a liquid inlet coupled to the liquid outlet of the filter via a first pipe, the first pipe including an inclined portion coupled to the liquid inlet of the storage tank, the inclined portion being oriented at an acute angle relative to the horizontal orientation axis of the storage tank. The storage tank includes an upper portion having a first lateral dimension above the liquid inlet and a lower portion having a second lateral dimension smaller than the first lateral dimension below the liquid inlet. The upper portion has a circular cross-section in a downward axial direction of the storage tank. The upper portion of the storage tank has a streamlined inner surface extending downward from the upper portion of the upper portion to the lower portion of the upper portion of the storage tank. The first lateral dimension is the lateral dimension at the widest point of the upper portion, and the second lateral dimension is the lateral dimension at the widest point of the lower portion. A buffer tank is coupled to a filter, wherein the buffer tank supplies liquid from the buffer tank to the filter. The buffer tank has a high level sensor and a low level sensor. The high level sensor is used to sense the highest permissible liquid level in the buffer tank, and the low level sensor is used to sense the minimum permissible liquid level in the buffer tank, so that the liquid level is maintained between the high level sensor and the low level sensor.

[0005] Another embodiment disclosed herein relates to a system for distributing liquids, including a filter, a distribution pump, a storage tank, a first pipe, a second pipe, and a buffer tank. The filter is used to filter the liquid prior to distribution. The distribution pump is used to distribute the filtered liquid. The storage tank, located between the filter and the distribution pump, includes a liquid inlet coupled to the filter. The storage tank includes a first portion above the liquid inlet and a second portion below the liquid inlet, the first portion having a first lateral dimension greater than the second portion having a second lateral dimension. The first portion has a circular cross-section in a downward axial direction of the storage tank. The upper portion of the storage tank has a streamlined inner surface extending downward from the upper portion of the upper portion to the lower portion of the upper portion of the storage tank. The first lateral dimension is the lateral dimension at the widest point of the first portion, and the second lateral dimension is the lateral dimension at the widest point of the second portion. The first pipe couples the filter to the storage tank and conveys the filtered liquid into the storage tank. The first pipe includes an inclined portion oriented at an acute angle relative to the horizontal orientation axis of the storage tank. The second pipe is coupled to the storage tank and used to expel air bubbles from the storage tank to the outside atmosphere. A buffer tank is coupled to the filter, wherein the buffer tank supplies liquid from the buffer tank to the filter. The buffer tank has a high-level sensor and a low-level sensor. The high-level sensor senses the highest permissible liquid level in the buffer tank, and the low-level sensor senses the minimum permissible liquid level in the buffer tank, so that the liquid level is maintained between the high-level sensor and the low-level sensor.

[0006] Another aspect of this disclosure relates to a method for eliminating air bubbles from a liquid distribution system, comprising the steps of: allowing air-bubble-containing liquid to flow from a buffer tank into a filter, the buffer tank having a high-level sensor and a low-level sensor, the high-level sensor for sensing the highest permissible liquid level in the buffer tank, and the low-level sensor for sensing the minimum permissible liquid level in the buffer tank, such that the level of the air-bubble-containing liquid is maintained between the high-level sensor and the low-level sensor; allowing the air-bubble-containing liquid to flow from the filter into a liquid inlet of the tank via a first pipe to substantially fill the tank, wherein the first pipe includes an inclined portion coupled to the liquid inlet of the tank, the inclined portion being sharply angled relative to the horizontal orientation axis of the tank. The angle orientation of the tank includes an upper portion above a liquid inlet and a lower portion below a liquid inlet. The upper portion has a circular cross-section along the top-to-bottom axial direction of the tank. The upper portion of the tank has a streamlined inner surface that extends downward from the upper portion of the upper portion to the lower portion of the upper portion of the tank. All air bubbles accumulate in the upper portion of the tank. A first lateral dimension of the upper portion of the tank is larger than a second lateral dimension of the lower portion of the tank. The first lateral dimension is the lateral dimension at the widest point of the upper portion, and the second lateral dimension is the lateral dimension at the widest point of the lower portion. The tank also allows bubble-free liquid to flow out of the tank via a liquid outlet at the lower portion for dispensing to a substrate. Attached Figure Description

[0007] The nature of this disclosure can be better understood by reading it in conjunction with the accompanying drawings, and the following detailed description will also be helpful. It should be noted that, in accordance with industry standard practice, the various features are not drawn to scale. In fact, the dimensions of each feature may be arbitrarily increased or decreased for clarity of explanation.

[0008] Figure 1 This is a schematic diagram of a liquid dispensing system according to some embodiments;

[0009] Figure 2 An enlarged cross-sectional view of a small storage tank in a liquid distribution system according to some embodiments;

[0010] Figure 3A This is a flowchart of a method for dispensing liquid onto a semiconductor wafer using a liquid dispensing system according to some embodiments;

[0011] Figure 3B This is a flowchart of the exhaust procedure according to some embodiments;

[0012] Figure 4 This is a block diagram of a control unit for controlling a liquid dispensing system according to some embodiments.

[0013] [Symbol Explanation]

[0014] 100 Liquid Dispensing System

[0015] 102 Storage Containers

[0016] 104 Liquid

[0017] 106 Gas Inlet

[0018] 108 Compressed Gas Supply

[0019] 110 pipe

[0020] 112 valve

[0021] 114 sensors

[0022] 116 Liquid outlet

[0023] 117 pipes

[0024] 118 valve

[0025] 120 Buffer Tank

[0026] 122 Liquid Inlet

[0027] 124 Liquid outlet

[0028] 125 tube

[0029] 126 Gas outlet

[0030] 127 tubes

[0031] 130 ventilation valve

[0032] 132 High Liquid Level Sensor

[0033] 134 Low liquid level sensor

[0034] 140 filter

[0035] 142 Liquid Inlet

[0036] 144 Liquid outlet

[0037] 145 tube

[0038] 145A Inclined section

[0039] 146 Gas outlet

[0040] 147 tubes

[0041] 148 Ventilation Valve

[0042] 150 small storage tanks

[0043] 150U Upper

[0044] 150L Lower Section

[0045] 152 Liquid Inlet

[0046] 154 Liquid outlet

[0047] 155 tube

[0048] 156 Gas outlet

[0049] 157 tubes

[0050] 158 Ventilation Valve

[0051] 160 Distributor Pump

[0052] 162 Liquid Inlet

[0053] 164 Liquid outlet

[0054] 165 tube

[0055] 170 trap

[0056] 172 Liquid Inlet

[0057] 174 Liquid outlet

[0058] 175 tube

[0059] 176 Gas outlet

[0060] 177 tubes

[0061] 178 Ventilation Valve

[0062] 180 valve

[0063] 182 exhaust nozzle

[0064] 190 Semiconductor Wafer

[0065] 195 valve

[0066] 300 methods

[0067] 302 Steps

[0068] 304 Steps

[0069] 306 steps

[0070] 308 steps

[0071] 310 steps

[0072] 400 Control Unit

[0073] 402 processor

[0074] 404 Computer-readable storage media

[0075] 406 Computer Program Code

[0076] 408 bus

[0077] 410 I / O Interface

[0078] 412 Network Interface

[0079] 414 Network

[0080] 416 Sensor Parameters

[0081] 418 Pump Parameters

[0082] 420 Valve Parameters

[0083] D1 Lateral dimension

[0084] D2 Lateral dimension

[0085] θ angle

[0086] AA' Horizontal Orientation Axis Detailed Implementation

[0087] The following disclosure provides numerous different embodiments or examples to achieve different features of each embodiment. Specific examples of components, materials, values, steps, arrangements, or similar items are described below to simplify this disclosure. Of course, these examples are merely illustrative and not intended to be limiting. Other components, values, steps, materials, arrangements, or similar items are to be considered. For example, the formation of a first feature above or on a second feature in the following description may include embodiments where the first and second features are formed in direct contact, and may also include embodiments where additional features may be formed between the first and second features such that the first and second features are not in direct contact. Additionally, element symbols and / or letters may be repeated in various examples of this disclosure. This repetition is for simplicity and clarity and does not in itself indicate a relationship between the various embodiments and / or configurations discussed.

[0088] Furthermore, spatial relative terms, such as “below,” “under,” “lower,” “above,” “upper,” and the like, are used herein for ease of description to describe the relationship between one element or feature illustrated in the figures and another element(s) or feature(s). Apart from the directions depicted in the figures, spatial relative terms are intended to encompass different orientations of elements in use or operation. Devices may be oriented differently (rotated 90 degrees or in other directions), and the spatial relative descriptive terms used herein can therefore be interpreted in the same way.

[0089] During semiconductor manufacturing, various lithography processes are performed to form components on semiconductor wafers. Photoresist is applied to the wafer, and a photomask is used to pattern it for use in one or more subsequent etching processes. The cost of photoresist is a significant material cost in semiconductor manufacturing.

[0090] Bubbles generated during the photoresist dispensing process affect manufacturing yield. For example, the presence of bubbles in the photoresist solution deposited on the wafer can cause problems such as undesirable thickness variations, pinholes, and high particle counts. Bubbles can appear within the liquid dispensing system for various reasons. For example, the liquid dispensing system typically includes a filter used to trap bubbles and / or particulate contaminants in the photoresist solution. Over time, the particulate contaminants and / or bubbles trapped on the filter tend to block the high-viscosity photoresist as the photoresist solution passes through the filter, creating a pressure differential in the liquid dispensing system. This pressure differential generates bubbles in the filtered photoresist. Consequently, the small tanks that receive the filtered photoresist from the filter are ventilated more frequently to remove bubbles. However, the high ventilation frequency leads to significant photoresist waste, as a large amount of usable photoresist is also discharged into the drainage system each time the small tank is ventilated. Since the cost of photoresist increases with decreasing exposure wavelength, less waste helps improve profitability. In addition, as the frequency of ventilation steps increases, the time required to reload the dispensing pump also increases, thus reducing production efficiency.

[0091] In some embodiments, a small reservoir with improved bubble removal capability is provided between the filter and the distribution pump of the liquid distribution system. The small reservoir helps reduce the frequency of bubble removal and also helps improve production efficiency.

[0092] Figure 1 This is a schematic diagram of a liquid dispensing system 100 according to some embodiments. The liquid dispensing system 100 is used to dispense liquids for semiconductor manufacturing processes from a storage container 102 onto a semiconductor wafer 190. Examples of semiconductor manufacturing processes include, but are not limited to, lithography, film deposition, etching, stripping, cleaning, and planarization. In some embodiments, the liquid dispensing system 100 includes a storage container 102, a buffer tank 120, a filter 140, a small tank 150, a dispensing pump 160, a trap 170, and a discharge nozzle 182.

[0093] Storage container 102 contains liquid 104 to be dispensed to semiconductor wafer 190. In some embodiments, liquid 104 is a chemical solution for use in photolithography processes. In some embodiments, liquid 104 is a photoresist solution. In some embodiments, liquid 104 is a developing solution for developing photoresist. Storage container 102 includes a gas inlet 106 located at the top of storage container 102 for receiving compressed gas from compressed gas supply 108. Examples of compressed gas include, but are not limited to, inert gases such as nitrogen, helium, or the like. Storage container 102 also includes a liquid outlet 116 located at the top of storage container 102. Liquid outlet 116 is coupled via pipe 117 to buffer tank 120 for supplying a large quantity of liquid 104 from storage container 102 to buffer tank 120. Valve 118 is coupled to pipe 117 to control the flow of liquid 104 from storage container 102 to buffer tank 120.

[0094] Compressed gas supply 108 is connected via pipe 110 to gas inlet 106 of storage container 102. Valve 112 is coupled to pipe 110 to control the flow of compressed gas in pipe 110. Sensor 114 is coupled to pipe 110 to monitor the pressure of compressed gas flowing through pipe 110 and, in a step, to generate a signal when the pressure of the compressed gas is insufficient to move liquid from storage container 102 to buffer tank 120. The signal can be used as an alarm to notify the stepper or automatic controller (e.g., control unit 400). Figure 4The compressed gas supply 108 is empty or malfunctioning. The compressed gas supplied by the compressed gas supply 108 causes liquid to flow out of the storage container 102 and into the buffer tank 120 via pipe 117. Valve 118 is coupled to pipe 117 to control the flow of liquid 104 from the storage container 102 to the buffer tank 120. Valve 118 is normally closed and opens in response to a control signal from control unit 400 requesting refilling of the buffer tank 120. However, using compressed gas increases the risk of air bubbles forming in the liquid 104, and air bubbles negatively impact the production process. Therefore, air bubbles are removed, or at least eliminated, before the liquid 104 is dispensed by the dispensing pump 160.

[0095] Buffer tank 120 is downstream of storage container 102 and is adapted to regulate the flow rate of liquid 104 from storage container 102 and maintain liquid 104 at a required level. Buffer tank 120 includes a liquid inlet 122, a liquid outlet 124, and a gas outlet 126. Liquid inlet 122 and gas outlet 126 are arranged in the upper part of buffer tank 120, while liquid outlet 124 is arranged in the lower part of buffer tank 120. This configuration allows liquid 104 to enter buffer tank 120 near the top and be drawn from the bottom of buffer tank 120 to be delivered to filter 140. Air bubbles in buffer tank 120 are retained at the top for easy removal from buffer tank 120. In some embodiments, liquid inlet 122 and liquid outlet 124 are arranged in different portions of buffer tank 120. Liquid inlet 122 is coupled to storage container 102 via pipe 117 for receiving a large quantity of liquid 104 from storage container 102. Liquid outlet 124 is coupled to filter 140 via pipe 125 for supplying a large quantity of liquid 104 from buffer tank 120 to filter 140. Gas outlet 126 is coupled to pipe 127 for discharging air bubbles accumulated in the upper part of buffer tank 120 to the atmosphere outside buffer tank 120. Vent valve 130 is coupled to pipe 127 for controlling the discharge of air bubbles from buffer tank 120 to the atmosphere. Vent valve 130 is normally closed and periodically discharges air bubbles from buffer tank 120 by opening and closing vent valve 130.

[0096] Buffer tank 120 includes a plurality of sensors for maintaining liquid 104 at an appropriate level. In some embodiments, the level of liquid 104 is maintained between a high level sensor 132 and a low level sensor 134. The high level sensor 132 senses the highest permissible liquid level in buffer tank 120. The low level sensor 134 senses the minimum permissible liquid level in buffer tank 120. When the liquid level of 104 in buffer tank 120 is low enough to trigger the low level sensor 134, the low level sensor 134 generates a signal indicating a low liquid level in buffer tank 120. In response to the signal from the low level sensor 134, control unit 400 sends a control signal to open valves 112 and 118 to begin supplying liquid 104 from storage container 102 to buffer tank 120 to refill buffer tank 120. On the other hand, when the liquid level of liquid 104 rises to a level that triggers the high liquid level sensor 132, the high liquid level sensor 132 generates a signal indicating the high liquid level in the buffer tank 120. In response to the signal from the high liquid level sensor 132, the control unit 400 sends a control signal to close valves 112 and 118 to stop the supply of liquid 104 from the storage container 102 to the buffer tank 120.

[0097] Filter 140 is downstream of buffer tank 120 and is adapted to filter liquid discharged from buffer tank 120 to remove contaminants, such as foreign matter or condensate and / or air bubbles, from liquid 104 before it is pumped to distribution pump 160. In some embodiments, filter 140 is formed of a porous media, such as a sieve or membrane. Filter 140 includes a liquid inlet 142, a liquid outlet 144, and a gas outlet 146. Liquid inlet 142 is coupled to buffer tank 120 via pipe 125 for receiving liquid 104 from buffer tank 120. Liquid outlet 144 is coupled to a small tank 150 via pipe 145 for supplying filtered liquid from filter 140 to small tank 150. Gas outlet 146 is coupled to pipe 147 for discharging air bubbles accumulated in the upper part of filter 140 to the atmosphere outside filter 140. Vent valve 148 is coupled to pipe 147 to control the discharge of air bubbles from filter 140 to the atmosphere. Vent valve 148 is normally closed and periodically discharges air bubbles from filter 140 by opening and closing vent valve 148.

[0098] After a period of use and as the amount of contaminants collected by filter 140 increases, the contaminants tend to block the liquid as it passes through, resulting in increased pressure within filter 140. This increased pressure leads to an increase in the amount of air bubbles in the filtered liquid. Before the filtered liquid is distributed by distribution pump 160, the air bubbles formed in the filtered liquid need to be removed or at least reduced by small storage tank 150.

[0099] Small tank 150 is downstream of filter 140. Before being dispensed by distribution pump 160, small tank 150 receives the filtered liquid from filter 140 and is adapted to prevent air bubbles from accumulating in the filtered liquid. Small tank 150 includes a liquid inlet 152, a liquid outlet 154, and a gas outlet 156. In some embodiments, liquid inlet 152 is located on a side wall of small tank 150, liquid outlet 154 is located at the bottom of small tank 150, and gas outlet 156 is located at the top of small tank 150. Liquid inlet 152 is coupled to filter 140 via pipe 145 for receiving filtered liquid from filter 140. Liquid outlet 154 is coupled to distribution pump 160 via pipe 155 for supplying filtered liquid from small tank 150 to distribution pump 160. Gas outlet 156 is coupled to pipe 157 for discharging air bubbles accumulated in the upper part of small tank 150 to the atmosphere outside small tank 150. A vent valve 158 is coupled to pipe 157 to control the discharge of air bubbles from the small tank 150. The vent valve 158 is normally closed and periodically discharges air bubbles from the small tank 150 by opening and closing the vent valve 158. In normal operation, filtered liquid 104 enters the small tank 150 near the top via pipe 145 and liquid inlet 152, and is drawn from the top of the small tank 150 to be delivered to the distribution pump 160 via liquid outlet 154 and pipe 155. Due to the difference in specific gravity, air bubbles tend to accumulate at the top of the small tank 150, while liquid tends to accumulate at the bottom. Therefore, air bubbles accumulated at the top of the small tank 150 can be substantially removed by ventilation through gas outlet 156 and pipe 157.

[0100] The small reservoir 150 and pipes 145 and 157 are designed to enhance the bubble removal capacity of the small reservoir 150. Therefore, bubbles in the filtered liquid can be substantially removed before being delivered to the distribution pump 160, which in turn helps reduce defects formed on the semiconductor wafer 190. The enhanced venting capacity of the small reservoir 150 also helps reduce the frequency of the ventilation step used to remove bubbles from the small reservoir 150. Thus, excessive waste of liquid available in other methods due to frequent ventilation is avoided, and the time required to reload the distribution pump 160 is reduced.

[0101] Dispensing pump 160 is downstream of small reservoir 150 and is used to pump liquid 104 from buffer tank 120, through filter 140 and small reservoir 150, and to discharge nozzle 182 for deposition on semiconductor wafer 190. In some embodiments, dispensing pump 160 is a gas pressure driven pump. In some embodiments, dispensing pump 160 includes a liquid inlet 162 and a liquid outlet 164. Liquid inlet 162 is coupled to small reservoir 150 via pipe 155 for receiving filtered liquid from small reservoir 150. Liquid outlet 164 is coupled to trap 170 via pipe 165 for supplying filtered liquid to trap 170.

[0102] The trap 170 is downstream of the distribution pump 160 and is used to remove air bubbles from the filtered liquid before it is delivered to the discharge nozzle 182. In some embodiments, the trap 170 includes a liquid inlet 172, a liquid outlet 174, and a gas outlet 176. The liquid inlet 172 is coupled to the distribution pump 160 via a pipe 165 for receiving filtered liquid discharged from the distribution pump 160. The liquid outlet 174 is coupled to the discharge nozzle 182 via a pipe 175 for supplying filtered liquid to the discharge nozzle 182. A supply control valve 180 is coupled to the pipe 175 for controlling the flow of filtered liquid discharged from the distribution pump 160 to the discharge nozzle 182. The gas outlet 176 is coupled to the pipe 177 for discharging air bubbles accumulated in the upper part of the trap 170 to the atmosphere outside the trap 170. A vent valve 178 is coupled to the pipe 177 for controlling the discharge of air bubbles from the trap 170. Ventilation valve 178 is normally closed, and bubbles are periodically discharged from trap 170 by opening and closing ventilation valve 178.

[0103] The discharge nozzle 182 is adapted to dispense (e.g., spray) filtered liquid onto the surface of the semiconductor wafer 190. In some embodiments, the discharge nozzle 182 dispenses filtered liquid as the semiconductor wafer 190 rotates.

[0104] In some embodiments, the liquid dispensing system 100 is controlled by a control unit 400, which controls the dispensing pump 160 and valves 112, 118, vent valve 130, vent valve 148, vent valve 158, vent valve 178 and 180 in response to data and / or signals from one or more of sensors 132 and 134.

[0105] Figure 2This is an enlarged cross-sectional view of a small reservoir 150 according to some embodiments. In some embodiments, to help effectively eliminate and / or remove air bubbles from the small reservoir 150, the lateral dimension D1 of the upper portion 150U of the small reservoir 150 above the liquid inlet 152 is larger than the lateral dimension D2 of the lower portion 150L. The increased volume at the upper portion 150U of the small reservoir 150 allows for the collection of more air bubbles in the top gap of the small reservoir 150. Consequently, the air bubbles are easily released into the atmosphere from the top of the small reservoir 150 via the pipe 157 and the vent valve 158. In some embodiments, the interior of the upper portion 150U of the small reservoir 150 has a streamlined cross-section that is circular, semi-circular, or semi-elliptical. The streamlined shape helps reduce turbulence along the inner surface of the upper portion 150U, which helps reduce air bubble formation as the filtered liquid flows into the small reservoir 150. Additionally, in some embodiments, the pipe 145 for supplying the filtered liquid from the filter 140 to the small reservoir 150 has an inclined portion 145A. The end of the inclined portion 145A of pipe 145 is sized to mate with the liquid inlet 152 of small tank 150. The inclined portion 145A of pipe 145 is oriented at an angle relative to the horizontal orientation axis A-A' of small tank 150. In various embodiments, the angle is an acute angle ranging from about 1 degree to about 90 degrees. In some embodiments, the angle is about 20 degrees. If the angle is too large, additional energy is used in some cases to pump the liquid into small tank 150. In some cases, if the angle is too small, air bubbles are trapped in the pipe. The inclined portion 145A of pipe 145 allows filtered liquid containing air bubbles to flow through pipe 145 and enter the liquid inlet 152 of small tank 150 at an angle. The inclined portion 145A of pipe 145 promotes the migration of air bubbles within pipe 145 to the upper portion 150U of small tank 150, and thereby helps to prevent air bubbles from being trapped in pipe 145. Increasing the angle θ helps facilitate smooth fluid distribution from pipe 145 to the interior of small tank 150. Generally, a larger angle θ allows bubbles to move more easily to the top gap of small tank 150. Furthermore, in some embodiments, the lateral dimension (i.e., diameter) of pipe 157 is increased to allow larger bubbles to exit small tank 150. In some embodiments, the diameter of pipe 157 is greater than about 1 / 8 inch but less than the lateral dimension of the lower portion 150L of small tank 150. In some embodiments, the diameter of pipe 157 is less than about 1 / 2 inch.

[0106] Figure 3A This is a flowchart of a method 300 for dispensing liquid 104 onto a semiconductor wafer 190 using a liquid dispensing system 100 according to some embodiments. The control unit 400 ( Figure 4 Control one or more components of the liquid distribution system 100 to perform method 300.

[0107] Method 300 includes step 302, wherein a predetermined amount of liquid (e.g., liquid 104) is supplied from storage container 102 to buffer tank 120. In response to a control signal from control unit 400 requesting filling of buffer tank 120, valves 112 and 118 are opened. Gas from compressed gas supply 108 compresses liquid 104 within storage container 102, causing liquid 104 in storage container 102 to flow into buffer tank 120. Liquid 104 is released from the bottom of storage container 102 to allow air bubbles in liquid 104 to reach the top of storage container 102 and to minimize the distribution of air bubbles in liquid 104 to buffer tank 120. In response to receiving a signal from the high level sensor 132 in the buffer tank 120, indicating that a predetermined amount of liquid 104 has flowed into the buffer tank 120, the control unit 400 sends a control signal to close valves 112 and 118 to stop the supply of liquid 104 from the storage container 102 to the buffer tank 120.

[0108] In step 304, before dispensing liquid 104 from buffer tank 120 to dispensing pump 160, air bubbles in liquid 104 are vented to the atmosphere outside liquid dispensing system 100.

[0109] In step 306, in response to a control signal sent from control unit 400, a substantially bubble-free amount of liquid 104 is drawn from buffer tank 120 by dispensing pump 160. In step 306, liquid 104 flows from buffer tank 120 to dispensing pump 160 via filter 140 and small tank 150.

[0110] In step 308, before dispensing liquid 104 from the dispensing pump 160 to the discharge nozzle 182, air bubbles in liquid 104 are vented to the atmosphere outside the liquid dispensing system 100.

[0111] In step 310, in response to a control signal sent by the self-control unit 400, the dispensing pump 160 dispenses liquid 104 via the trap 170 to the discharge nozzle 182, and the discharge nozzle 182 applies liquid 104 to the semiconductor wafer 190. During the dispensing step, vent valves 130, 148, 158, and 178 are closed, while the supply control valve 180 is opened in response to a control signal sent by the self-control unit 400. In some embodiments, liquid is drawn from the buffer tank 120 by the dispensing pump 160 each time the discharge nozzle 182 applies liquid 104 to the semiconductor wafer 190. The opening and closing of the supply control valve 180 is controlled by the control unit 400. Steps 304 to 306 are repeated until the liquid level of liquid 104 in the buffer tank 120 is sufficiently low to trigger the low level sensor 134. In response to a signal from a low level sensor 134 indicating a low liquid level in the buffer tank 120, method 300 performs step 302, wherein control unit 400 sends a control signal to open valves 112 and 118 to begin supplying liquid 104 from storage container 102 to buffer tank 120 to refill buffer tank 120.

[0112] Figure 3B This is a flowchart of ventilation step 320 according to some embodiments. Ventilation step 320 can be used as... Figure 3A Examples of steps 304 or 308 in the process.

[0113] exist Figure 3BIn this process, ventilation step 320 includes steps 312 and 314. In step 312, control unit 400 determines whether a predetermined amount of liquid dispensing step (step 312a) performed by dispensing pump 160 or a predetermined time period (step 312b) associated with one or more of the ventilation buffer tank 120, filter 140, small tank 150, and trap 170 has been achieved. If the predetermined amount of liquid dispensing step performed by dispensing pump 160 or the predetermined time period associated with one or more of the buffer tank 120, filter 140, small tank 150, and trap 170 has been achieved, then method 300 executes step 314 (a branch from step 312a or step 312b). In step 314, control unit 400 sends a control signal to open one or more corresponding ventilation valves 130, 148, 158, and 178 to expel air bubbles. After a predetermined time period, the control unit 400 sends a control signal to close one or more corresponding ventilation valves 130, 148, 158, and 178, terminating the ventilation step 320. On the other hand, if the predetermined amount of liquid dispensing step (step 312a) performed by the dispensing pump 160 or the predetermined time period (step 312b) associated with any of the buffer tank 120, filter 140, small tank 150, and trap 170 has not been completed, the ventilation step 320 terminates (without branching from step 312b) and transitions from step 314.

[0114] Figure 4This is a block diagram of a control unit 400 for controlling steps of a liquid dispensing system 100 according to some embodiments. In some embodiments, the control unit 400 is a general-purpose computing device including a hardware processor 402 and a non-transitory computer-readable storage medium 404 encoded with computer program code 406 (i.e., a set of executable instructions), i.e., the computer-readable storage medium stores computer program code 406 (i.e., a set of executable instructions). The computer-readable storage medium 404 is also encoded with instructions 407 for connection to dispensing pump 160, valves 112, 118, vent valves 130, 148, 158, 178, and 180, and high-level sensors 132 and low-level sensors 134 of the liquid dispensing system 100. The processor 402 is electrically coupled to the computer-readable storage medium 404 via a bus 408. The processor 402 is also electrically coupled to an I / O interface 410 via a bus 408. Network interface 412 is also electrically connected to processor 402 via bus 408. Network interface 412 is connected to network 414 so that processor 402 and computer-readable storage medium 404 can be connected to external components via network 414. Processor 402 is used to execute computer program code 406 encoded in computer-readable storage medium 404 so that control unit 400 can be used to perform the steps described with reference to liquid dispensing system 100.

[0115] In some embodiments, the processor 402 is a central processing unit (CPU), a multiprocessor, a distributed processing system, an application-specific integrated circuit (ASIC), and / or a suitable processing unit.

[0116] In some embodiments, the computer-readable storage medium 404 is an electronic, magnetic, optical, electromagnetic, infrared, and / or semiconductor system (or device or apparatus). For example, the computer-readable storage medium 404 includes semiconductor or solid-state memory, magnetic tape, removable computer disk, random access memory (RAM), read-only memory (ROM), rigid disk, and / or optical disk. In some embodiments using optical disk, the computer-readable storage medium 404 includes compact disk read-only memory (CD-ROM), CD-R / W, and / or digital video disc (DVD).

[0117] In some embodiments, computer-readable storage medium 404 stores computer program code 406, which is used to cause control unit 400 to perform the steps described with reference to liquid dispensing system 100. In some embodiments, computer-readable storage medium 404 also stores information required to perform the steps described with reference to liquid dispensing system 100, such as sensor parameters 416 (such as liquid levels detected by high level sensor 132 and low level sensor 134 and air pressure detected by sensor 114), pump parameters 418 (such as predetermined numbers of liquids dispensed by dispensing pump 160), and valve parameters 420 (such as predetermined periods for opening and closing vent valves 130, 148, 158, and 178, and / or a set of executable instructions for performing the steps described with reference to liquid dispensing system 100).

[0118] In some embodiments, computer-readable storage medium 404 stores instructions 407 for connection to liquid dispensing system 100. Instructions 407 enable processor 402 to generate step instructions readable by dispensing pump 160, valve 112, valve 118, vent valve 130, vent valve 148, vent valve 158, vent valve 178 and valve 180, and high level sensor 132 and low level sensor 134 of liquid dispensing system 100, to effectively implement the steps described with reference to liquid dispensing system 100.

[0119] The control unit 400 includes an I / O interface 410. The I / O interface 410 is coupled to an external circuit system. In some embodiments, the I / O interface 410 includes a keyboard, keypad, mouse, trackball, trackpad, touchscreen, and / or cursor arrow keys for exchanging information and commands with the processor 402.

[0120] The control unit 400 also includes a network interface 412 coupled to the processor 402. The network interface 412 allows the control unit 400 to communicate with a network 414, to which one or more other computer systems are connected. The network interface 412 includes a wireless network interface, such as BlueTooth, Wi-Fi, WiMAX, GPRS, or WCDMA; or a wired network interface, such as Ethereum, USB, or IEEE-1394. In some embodiments, the steps described with reference to the liquid dispensing system 100 are implemented in two or more control units 400, and information such as sensor, pump, and valve information is exchanged between the different control units 400 via the network 414.

[0121] One embodiment of this disclosure relates to a system for dispensing liquid. The system includes a filter adapted to filter liquid and provide filtered liquid at a liquid outlet of the filter. The system also includes a tank having a liquid inlet coupled to the liquid outlet of the filter via a first pipe. The tank includes an upper portion having a first lateral dimension and a lower portion having a second lateral dimension smaller than the first lateral dimension. The upper portion of the tank is located above the liquid inlet of the tank. In some embodiments, the upper portion has a circular, semi-circular, or semi-elliptical cross-section. In some embodiments, the liquid inlet of the tank extends through a sidewall of the tank. In some embodiments, the first pipe includes a first portion coupled to the liquid outlet of the filter and a second portion coupled to the liquid inlet of the tank. The second portion of the first pipe is oriented at an angle of less than 90 degrees relative to the horizontal orientation axis of the tank. In some embodiments, the second portion of the first pipe is oriented at an angle of about 20 degrees relative to the horizontal orientation axis of the tank. In some embodiments, the tank further includes a gas outlet for discharging bubbles accumulated in the upper portion into the atmosphere outside the tank. In some embodiments, the system further includes a second pipe coupled to the gas outlet of the tank. The second pipe has a diameter greater than about 1 / 8 inch and less than about 1 / 2 inch. In some embodiments, the system further includes a liquid outlet that allows filtered liquid to flow out of the tank. In some embodiments, the liquid outlet is located at the bottom of the tank. In some embodiments, the system further includes a distribution pump coupled to the liquid outlet of the tank via a third pipe.

[0122] Another embodiment of this disclosure relates to a system for dispensing liquid. The system includes a filter for filtering the liquid prior to dispensing, a dispensing pump for dispensing the filtered liquid, and a reservoir located between the filter and the dispensing pump. A first portion of the reservoir has a lateral dimension larger than that of a second portion of the reservoir, and this second portion is lower than the first portion. The system also includes a first pipe that couples the filter to the reservoir and for conveying the filtered liquid into the reservoir. An inclined portion of the first pipe is oriented at an acute angle relative to the horizontal orientation axis of the reservoir. The system also includes a second pipe coupled to the reservoir and for venting air bubbles from the reservoir to the atmosphere outside the reservoir. In some embodiments, the first portion of the reservoir has a circular, semi-circular, or semi-elliptical cross-section. In some embodiments, the second pipe has a diameter smaller than the lateral dimension of the second portion of the reservoir. In some embodiments, the second pipe has a diameter greater than about 1 / 8 inch and less than about 1 / 2 inch. In some embodiments, the system further includes a buffer reservoir coupled to the filter. The buffer reservoir is used to supply liquid from the buffer reservoir to the filter. In some embodiments, the system further includes a storage container coupled to a buffer tank. The storage container is used to supply liquid from the storage container to the buffer tank. In some embodiments, the system further includes a discharge nozzle for dispensing filtered liquid to a substrate. A dispensing pump is used to dispense filtered liquid to the discharge nozzle.

[0123] Another aspect of this disclosure relates to a method for eliminating air bubbles from a liquid distribution system. This method includes the step of allowing air-bubble-containing liquid to flow from a filter into a liquid inlet of a tank to substantially fill the tank. Substantially, all air bubbles accumulate in the upper portion of the tank, where the lateral dimension of the upper portion of the tank is greater than the lateral dimension of the lower portion. The method further includes the step of allowing substantially bubble-free liquid to flow out of the tank via a liquid outlet at the lower portion for distribution to a substrate. In some embodiments, the method further includes discharging the air bubbles accumulated in the upper portion of the tank to the atmosphere outside the tank via a pipe coupled to a gas outlet at the top of the tank. The diameter of this pipe is greater than the lateral dimension of the lower portion of the tank. In some embodiments, the method further includes the step of flowing liquid through a filter to provide air-bubble-containing liquid.

[0124] Another aspect of this disclosure relates to a system for distributing liquids, including a filter, a storage tank, and a buffer tank. The filter is suitable for filtering liquids and providing filtered liquid at the filter's liquid outlet. The storage tank includes a liquid inlet coupled to the liquid outlet of the filter via a first pipe, the first pipe including an inclined portion coupled to the liquid inlet of the storage tank, the inclined portion being oriented at an acute angle relative to the horizontal orientation axis of the storage tank, wherein the storage tank includes an upper portion having a first lateral dimension above the liquid inlet and a lower portion having a second lateral dimension smaller than the first lateral dimension below the liquid inlet, the upper portion having a circular cross-section in a downward axial direction of the storage tank, the upper portion of the storage tank having a streamlined inner surface extending downward from the upper portion of the upper portion of the storage tank to the lower portion of the upper portion of the storage tank, wherein the first lateral dimension is the lateral dimension at the widest point of the upper portion, and the second lateral dimension is the lateral dimension at the widest point of the lower portion. A buffer tank is coupled to a filter, wherein the buffer tank supplies liquid from the buffer tank to the filter. The buffer tank has a high-level sensor and a low-level sensor, the high-level sensor sensing the highest permissible liquid level in the buffer tank, and the low-level sensor sensing the minimum permissible liquid level in the buffer tank, such that the liquid level is maintained between the high-level sensor and the low-level sensor. In some embodiments, a liquid inlet of the tank extends through a sidewall of the tank. In some embodiments, a first pipe includes a horizontal portion coupled to a liquid outlet of the filter, the horizontal portion of the first pipe being parallel to the horizontal orientation axis of the tank. In some embodiments, an inclined portion of the first pipe is oriented at an angle of 20 degrees relative to the horizontal orientation axis of the tank. The tank also includes a gas outlet for discharging air bubbles accumulated in the upper part into the atmosphere outside the tank.

[0125] Another embodiment disclosed herein relates to a system for distributing liquids, including a filter, a distribution pump, a storage tank, a first pipe, a second pipe, and a buffer tank. The filter is used to filter the liquid prior to distribution. The distribution pump is used to distribute the filtered liquid. The storage tank, located between the filter and the distribution pump, includes a liquid inlet coupled to the filter. The storage tank includes a first portion above the liquid inlet and a second portion below the liquid inlet, the first portion having a first lateral dimension greater than the second portion having a second lateral dimension. The first portion has a circular cross-section in a downward axial direction of the storage tank. The upper portion of the storage tank has a streamlined inner surface extending downward from the upper portion of the upper portion to the lower portion of the upper portion of the storage tank. The first lateral dimension is the lateral dimension at the widest point of the first portion, and the second lateral dimension is the lateral dimension at the widest point of the second portion. The first pipe couples the filter to the storage tank and conveys the filtered liquid into the storage tank. The first pipe includes an inclined portion oriented at an acute angle relative to the horizontal orientation axis of the storage tank. A second pipe is coupled to a storage tank to expel air bubbles from the storage tank to the atmosphere outside the tank. A buffer tank is coupled to a filter, wherein the buffer tank supplies liquid from the buffer tank to the filter. The buffer tank has a high-level sensor and a low-level sensor. The high-level sensor senses the highest permissible liquid level in the buffer tank, and the low-level sensor senses the minimum permissible liquid level in the buffer tank, such that the liquid level is maintained between the high-level sensor and the low-level sensor. In some embodiments, the second pipe has a diameter greater than 1 / 8 inch and less than 1 / 2 inch. In some embodiments, the system further includes a storage container coupled to the buffer tank, wherein the storage container supplies liquid from the storage container to the buffer tank. In some embodiments, the system further includes a discharge nozzle for dispensing filtered liquid to a substrate, wherein a dispensing pump dispenses filtered liquid to the discharge nozzle.

[0126] Another aspect of this disclosure relates to a method for eliminating air bubbles from a liquid distribution system, comprising the steps of: allowing air-bubble-containing liquid to flow from a buffer tank into a filter, the buffer tank having a high-level sensor and a low-level sensor, the high-level sensor for sensing the highest permissible liquid level in the buffer tank, and the low-level sensor for sensing the minimum permissible liquid level in the buffer tank, such that the level of the air-bubble-containing liquid is maintained between the high-level sensor and the low-level sensor; allowing the air-bubble-containing liquid to flow from the filter into a liquid inlet of the tank via a first pipe to substantially fill the tank, wherein the first pipe includes an inclined portion coupled to the liquid inlet of the tank, the inclined portion being sharply angled relative to the horizontal orientation axis of the tank. The angle orientation of the tank includes an upper portion above a liquid inlet and a lower portion below a liquid inlet. The upper portion has a circular cross-section along the top-to-bottom axial direction of the tank. The upper portion of the tank has a streamlined inner surface that extends downward from the upper portion of the upper portion to the lower portion of the upper portion of the tank. All air bubbles accumulate in the upper portion of the tank. A first lateral dimension of the upper portion of the tank is larger than a second lateral dimension of the lower portion of the tank. The first lateral dimension is the lateral dimension at the widest point of the upper portion, and the second lateral dimension is the lateral dimension at the widest point of the lower portion. The tank also allows bubble-free liquid to flow out of the tank via a liquid outlet at the lower portion for dispensing to a substrate.

[0127] The foregoing summary outlines features or examples of several embodiments to enable those skilled in the art to better understand the nature of this disclosure. Those skilled in the art should understand that this disclosure can be readily used as the basis for designing or modifying other processes and structures to achieve the same purposes and / or benefits as the embodiments or examples described herein. Those skilled in the art should also recognize that such equivalent structures do not depart from the spirit and scope of this disclosure, and that various changes, substitutions, and modifications can be made without departing from the spirit and scope of this disclosure.

Claims

1. A system for dispensing liquids, characterized in that, include: A filter suitable for filtering a liquid and providing a filtered liquid at a liquid outlet of the filter; A storage tank includes a liquid inlet coupled to a liquid outlet of a filter via a first pipe, the first pipe including an inclined portion coupled to the liquid inlet of the storage tank, the inclined portion being oriented at an acute angle relative to a horizontal orientation axis of the storage tank, wherein the storage tank includes an upper portion having a first lateral dimension above the liquid inlet and a lower portion having a second lateral dimension smaller than the first lateral dimension below the liquid inlet, the upper portion having a circular cross-section in a downward axial direction of the storage tank, the upper portion of the storage tank having a streamlined inner surface extending downward from the upper portion of the upper portion of the storage tank to the lower portion of the upper portion of the storage tank, wherein the first lateral dimension is the lateral dimension at the widest point of the upper portion, and the second lateral dimension is the lateral dimension at the widest point of the lower portion; and A buffer tank, coupled to the filter, is provided for supplying the liquid from the buffer tank to the filter. The buffer tank has a high level sensor and a low level sensor. The high level sensor is used to sense a maximum permissible liquid level in the buffer tank, and the low level sensor is used to sense a minimum permissible liquid level in the buffer tank, such that the liquid level is maintained between the high level sensor and the low level sensor.

2. The system for dispensing liquid according to claim 1, characterized in that, The liquid inlet of the tank extends through one side wall of the tank.

3. The system for dispensing liquid according to claim 1, characterized in that, The first pipe includes a horizontal portion coupled to the liquid outlet of the filter, the horizontal portion of the first pipe being parallel to the horizontal orientation axis of the storage tank.

4. The system for dispensing liquid according to claim 3, characterized in that, The inclined portion of the first pipe is oriented at an angle of 20 degrees relative to the horizontal orientation axis of the storage tank.

5. The system for dispensing liquid according to claim 1, characterized in that, The storage tank also includes a gas outlet for discharging the bubbles that have accumulated in the upper part into the atmosphere outside the storage tank.

6. A system for dispensing liquids, characterized in that, include: A filter for filtering a liquid before dispensing; A dispensing pump is used to dispense the filtered liquid; A storage tank, between a filter and a distribution pump, includes a liquid inlet coupled to the filter, wherein the storage tank includes a first portion above the liquid inlet and a second portion below the liquid inlet, the first portion having a first lateral dimension larger than the second portion having a second lateral dimension, the first portion having a circular cross-section in the top-to-bottom axial direction of the storage tank, the upper portion of the storage tank having a streamlined inner surface extending downward from the upper portion of the upper portion of the storage tank to the lower portion of the upper portion of the storage tank, wherein the first lateral dimension is the lateral dimension at the widest point of the first portion, and the second lateral dimension is the lateral dimension at the widest point of the second portion; A first tube, which couples the filter to the storage tank and delivers the filtered liquid into the storage tank, wherein the first tube includes an inclined portion oriented at an acute angle relative to a horizontal orientation axis of the storage tank; A second pipe is coupled to the storage tank and used to discharge air bubbles in the storage tank to the atmosphere outside the storage tank; as well as A buffer tank, coupled to the filter, is provided for supplying the liquid from the buffer tank to the filter. The buffer tank has a high level sensor and a low level sensor. The high level sensor is used to sense a maximum permissible liquid level in the buffer tank, and the low level sensor is used to sense a minimum permissible liquid level in the buffer tank, such that the liquid level is maintained between the high level sensor and the low level sensor.

7. The system for dispensing liquid according to claim 6, characterized in that, The second tube has a diameter greater than 1 / 8 inch and less than 1 / 2 inch.

8. The system for dispensing liquid according to claim 6, characterized in that, It also includes a storage container coupled to the buffer tank, wherein the storage container is used to supply the liquid from the storage container to the buffer tank.

9. The system for dispensing liquid according to claim 6, characterized in that, It also includes a discharge nozzle for distributing the filtered liquid to a substrate, wherein the distribution pump is used to distribute the filtered liquid to the discharge nozzle.

10. A method for eliminating air bubbles from a liquid distribution system, characterized in that, Includes the following steps: A liquid containing air bubbles is allowed to flow from a buffer tank into a filter. The buffer tank has a high level sensor and a low level sensor. The high level sensor is used to sense a maximum allowable liquid level in the buffer tank, and the low level sensor is used to sense a minimum allowable liquid level in the buffer tank, so that the level of the liquid containing air bubbles is maintained between the high level sensor and the low level sensor. The bubble-containing liquid is allowed to flow from the filter into a liquid inlet of a storage tank via a first pipe to substantially fill the tank. The first pipe includes an inclined portion coupled to the liquid inlet of the tank, the inclined portion being oriented at an acute angle relative to a horizontal orientation axis of the tank. The tank includes an upper portion above the liquid inlet and a lower portion below the liquid inlet. The upper portion has a circular cross-section along a downward axial direction of the tank. The upper portion of the tank has a streamlined inner surface extending downward from the upper portion of the upper portion to the lower portion of the upper portion. All bubbles accumulate in the upper portion of the tank. A first lateral dimension of the upper portion of the tank is greater than a second lateral dimension of the lower portion of the tank, wherein the first lateral dimension is the lateral dimension at the widest point of the upper portion, and the second lateral dimension is the lateral dimension at the widest point of the lower portion. A bubble-free liquid is discharged from the tank through a liquid outlet at the bottom of the tank for dispensing to a substrate.

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