Electrical tracking of multiphase microfluidic flow

Abstract

Embodiments of computer-implemented methods, systems, and apparatus for tracking multiphase flow in a microfluidic device are provided. The method includes receiving a first reading from a first sensor of the microfluidic device, the first reading representing the detection of fluid at an interface between the fluid and the first sensor, and receiving a second reading from a second sensor of the microfluidic device, the second reading representing the detection of fluid at an interface between the fluid and the second sensor, wherein the first sensor is located at a distance from the second sensor. The method further includes calculating the flow rate of the fluid in the microfluidic device based at least in part on the time difference between the detections by the first and second sensors and the distance between the first and second sensors.

Description

Background Technology

[0001] This invention generally relates to methods of manufacturing microfluidic devices and the resulting structures. More specifically, this invention relates to the electrical tracking of multiphase flows in microfluidic devices.

[0002] Microfluidics involves the precise control and manipulation of small volumes of fluid, typically confined to microscale channels and volumes generally in the submicroliter range. Microfluidic devices typically comprise microchannel loops with multiple channels. A key characteristic of microfluidics stems from the unique behavior of liquids at the microscale. Liquid flow in microfluidics is typically laminar. By fabricating structures with lateral dimensions in the micrometer range, volumes well below one nanoliter can be achieved. Microfluidic devices generally refer to microfabrication devices used for pumping, sampling, mixing, analyzing, and quantitatively supplying liquids. Summary of the Invention

[0003] Embodiments of the present invention relate to a computer-implemented method for electrically tracking multiphase flow in a microfluidic device. Non-limiting examples of the computer-implemented method include: receiving a first reading from a first sensor of the microfluidic device using a processor, the first reading representing the detection of fluid at an interface between the fluid and the first sensor; receiving a second reading from a second sensor of the microfluidic device using the processor, the second reading representing the detection of the fluid at an interface between the fluid and the second sensor, wherein the first sensor is located at a distance from the second sensor; and calculating the flow rate of the fluid in the microfluidic device using the processor based at least in part on the time difference between the detections by the first and second sensors and the distance between the first and second sensors.

[0004] Embodiments of the present invention relate to a system for performing electrical tracking of multiphase flow in a microfluidic device. A non-limiting example of the system includes a processor and a memory coupled to the processor. The processor is configured to receive a first reading from a first sensor of the microfluidic device, the first reading representing detection of fluid at an interface between the fluid and the first sensor; receive a second reading from a second sensor of the microfluidic device, the second reading representing detection of fluid at an interface between the fluid and the second sensor; and calculate the flow rate of the fluid in the microfluidic device based at least in part on the time difference between the detections of the first and second sensors and the distance between the first and second sensors.

[0005] Embodiments of the present invention relate to a method of manufacturing a microfluidic device for performing electrical tracking of multiphase flow in a microfluidic device. Non-limiting examples of manufacturing semiconductor devices include: forming a first wafer including first terminals of a first sensor and a second sensor; forming a second wafer including second terminals of the first sensor and the second sensor; and bonding the first wafer to the second wafer, wherein the first terminals in the first wafer are aligned with the second terminals of the second wafer.

[0006] Additional features and benefits are achieved through the technology of this invention. Embodiments and aspects of the invention are described in detail herein and are considered part of the claimed subject matter. For a better understanding, refer to the detailed description and accompanying drawings. Attached Figure Description

[0007] The proprietary details described herein are specifically pointed out and clearly claimed in the claims at the end of the specification. The foregoing and other features and advantages of embodiments of the invention will become apparent from the following detailed description taken in conjunction with the accompanying drawings, wherein:

[0008] Figure 1 A top view and a cross-sectional AA view of a microfluidic structure after processing operations according to one or more embodiments of the present invention are described.

[0009] Figure 2 A top view and a cross-sectional AA view of a microfluidic structure after processing operations according to one or more embodiments of the present invention are described.

[0010] Figure 3 A top view and a cross-sectional AA view of a microfluidic structure after processing operations according to one or more embodiments of the present invention are described.

[0011] Figure 4 A top view and a cross-sectional AA view of a microfluidic structure after processing operations according to one or more embodiments of the present invention are described.

[0012] Figure 5 A top view and a cross-sectional AA view of a microfluidic structure after processing operations according to one or more embodiments of the present invention are described.

[0013] Figure 6 A top view and a cross-sectional AA view of a microfluidic structure after processing operations according to one or more embodiments of the present invention are described.

[0014] Figure 7 A top view and a cross-sectional AA view of a microfluidic structure after processing operations according to one or more embodiments of the present invention are described.

[0015] Figure 8A microfluidic device according to one or more embodiments of the present invention is described;

[0016] Figure 9 Another microfluidic device according to one or more embodiments of the present invention is described;

[0017] Figure 10 Different microfluidic devices according to one or more embodiments of the present invention are described;

[0018] Figure 11 Another microfluidic device according to one or more embodiments of the present invention is described;

[0019] Figure 12 A microfluidic device according to one or more embodiments of the present invention is described;

[0020] Figure 13 A flowchart illustrating a method for manufacturing a microfluidic device according to one or more embodiments of the present invention is described;

[0021] Figure 14 A flowchart of a method for tracking multiphase fluids in microfluidics according to one or more embodiments of the present invention is shown; and

[0022] Figure 15 This is a block diagram illustrating an example of a processing system used to implement the teachings herein.

[0023] The figures described herein are illustrative. Many variations may be made to the figures or operations described herein without departing from the scope of the invention. For example, actions may be performed in a different order, or actions may be added, deleted, or modified. Furthermore, the term "coupling" and its variations describe a communication path between two elements and do not imply a direct connection between the elements without any intermediate elements / connections between them. All such variations are considered part of the specification.

[0024] In the accompanying drawings and the following detailed description of the embodiments, the various elements shown in the drawings are labeled with two or three digits. With very few exceptions, the leftmost digit of each reference numeral corresponds to the figure in which its element is first shown. Detailed Implementation

[0025] For the sake of brevity, conventional techniques related to the manufacture of semiconductor devices and integrated circuits (ICs) may or may not be described in detail herein. Furthermore, the various tasks and process steps described herein may be incorporated into more comprehensive procedures or processes with additional steps or functionalities not described in detail herein. In particular, many steps in the manufacture of semiconductor devices and semiconductor-based ICs are well-known; therefore, for the sake of brevity, many conventional steps will be mentioned only briefly or will be omitted entirely without providing well-known process details.

[0026] Turning now to an overview of the technology more specifically related to aspects of the present invention, microfluidic devices feature a user-chip interface and a closed flow path. The closed flow path facilitates the integration of functional elements (e.g., heaters, mixers, pumps, UV detectors, valves, etc.) into a single device while minimizing problems associated with leakage and evaporation. Analysis of liquid samples typically requires a series of steps (e.g., filtration, reagent dissolution, heating, washing, signal readout, etc.). Having multiple channels on a single device increases its footprint and therefore its manufacturing cost.

[0027] To track multiphase displacement within known microfluidic devices, optical methods can be used, which require the microfluidic device to be formed from a material that transmits light. Optical detection is also limited by diffraction and requires optical contrast between phases or the use of fluorescent particles to track the flow.

[0028] Turning now to an overview of aspects of the invention, one or more embodiments of the invention address the aforementioned disadvantages of the prior art by providing a microfluidic device with an integrated electrical sensor therein. In embodiments of the invention, the integrated electrical sensor is configured and arranged such that the microfluidic device can track the fluid-fluid interface over time, which further enables the acquisition of spatially resolved and time-dependent information on the position of each phase in a multiphase system for flow tracking. In some embodiments of the invention, the electrical sensor is a capacitive sensor configured to measure capacitance, and each fluid flowing through the microfluidic device can exhibit different dielectric properties, which can be measured by their effect on capacitance, which can be measured by one or more of the capacitive sensors. In embodiments of the invention, the electrical sensor is embedded in the channel wall to allow measurement of the fluid electrical properties as a function of time, which enables tracking of the movement of the fluid-fluid interface.

[0029] A method according to embodiments of the present invention may include measuring capacitance as a function of time at different points in a microfluidic device while establishing a multiphase (immiscible) flow. Abrupt changes in the capacitance signal are monitored, reflecting the passage of the interface between two terminals. Various quality factors, including but not limited to interface displacement velocity, channel saturation, and fluid wettability, can be calculated using the distance between sensors (which is known) and the time it takes for the fluid interface to pass through different sensors.

[0030] In one or more embodiments of the invention, the frequency for measuring capacitance can be tuned to a desired value / range. The frequency can be adjusted to increase the contrast in capacitance between the fluid phases to be measured. Furthermore, the frequency can be tuned to increase the sampling rate and capture higher interface velocities.

[0031] Now we turn to a more detailed description of aspects of the invention. Figure 1 A top view and a cross-sectional view (AA) depict a structure 100 after an initial set of fabrication operations for forming a final microfluidic device according to one or more embodiments of the invention. In embodiments of the invention, known fabrication operations have been used to form and pattern a hard mask 104 on an oxide layer 102 of the structure 100. As best shown in the top view, the pattern in the hard mask 104 includes openings 106 that expose portions of the oxide layer 102.

[0032] In some embodiments of the present invention, the hard mask 104 may include an oxygen-containing layer, such as a silicon oxide (SiO2) layer or a silicon oxynitride (SiON) layer; a substantially oxygen-free layer, such as a silicon nitride (SiN) layer or a silicon carbide (SiC) layer; or a substantially oxygen-free composite dielectric film. In some embodiments of the present invention, the hard mask 104 may be formed solely of tantalum nitride (TaN).

[0033] Figure 2 A top view and a section view (AA) depicting the structure 100 after processing operations according to one or more embodiments of the present invention. For example... Figure 2 As shown, hard mask 104 ( Figure 1The hard mask 104 (shown) has been removed. However, prior to removing the hard mask 104, oxide etching was performed to etch the exposed portions through the oxide layer 102 and form trenches filled with metal to form the contacts 202. According to an embodiment of the invention, each contact 202 will serve as the first terminal of the two-terminal sensor to be formed. The contacts 202 can be made of any suitable conductive material, such as metals (e.g., tungsten, titanium, tantalum, ruthenium, zirconium, cobalt, copper, aluminum, platinum), conductive metal compound materials (e.g., tantalum nitride, titanium nitride, tantalum carbide, titanium carbide, titanium aluminum carbide, tungsten silicide, tungsten nitride, cobalt silicide, nickel silicide), conductive carbon, or any suitable combination of these materials. In some embodiments of the invention, the contacts 202 comprise copper, cobalt, or tungsten. The conductive material used to form the contacts 202 may further include dopants introduced during or after deposition. In some embodiments of the invention, the contacts 202 may include a barrier metal pad (not shown). In one or more embodiments of the present invention, after the conductive material that has been deposited to form the contact 202 is formed, chemical mechanical planarization (CMP) is performed on the structure 100 to remove any excess conductive material and planarize the structure 100 to the level shown.

[0034] Figure 3 A top view and a section view (AA) of the structure 100 after processing operations according to one or more embodiments of the present invention are depicted. Figure 3 As shown, an additional oxide layer 302 is deposited on the top surface of oxide layer 102. In one or more embodiments of the invention, oxide layer 302 may be made of the same material as oxide layer 102. Any known method for forming oxide layer 302 may be used, such as chemical vapor deposition (CVD), plasma-enhanced CVD (PECVD), atomic layer deposition (ALD), flowable CVD, spin-coated dielectric, or physical vapor deposition (PVD).

[0035] Still referencing Figure 3 A hard mask 304 has been formed on the oxide layer 302 and patterned to include openings in one or more portions of the top surface of the underlying oxide layer 302.

[0036] Figure 4 A top view and a section view (AA) of the structure 100 after processing operations according to one or more embodiments of the present invention are depicted. Figure 4 As shown, hard mask 304 has been removed. However, after removing hard mask 304 ( Figure 3Before (as shown), the portion of oxide layer 302 not covered by hard mask 304 is etched to form an opening in oxide layer 302. The opening in oxide layer 302 is then filled with metal to form the bottom terminal 402 of the dual-terminal sensor to be formed. In an embodiment of the invention, hard mask 304 can be removed by applying CMP, which removes hard mask 304 and planarizes structure 100 to Figure 4 The horizontal plane is shown. The bottom terminal 402 is formed on the contact 202.

[0037] Figure 5 A top view and a section view (AA) of the structure 100 after processing operations according to one or more embodiments of the present invention are depicted. Figure 5 As shown, oxide layer 502 has been deposited on oxide layer 302 and bottom terminal 402 of structure 100. In one or more embodiments of the invention, oxide layer 502 is made of the same material as oxide layer 302 and / or oxide layer 102. Any known method of forming oxide layer 502 can be used.

[0038] like Figure 5 As shown, a hard mask 504 has been formed on the oxide layer 502. Any method can be used to form the hard mask 504. A top view of structure 100 shows that the hard mask 504 has been patterned to expose a portion of the top surface of the oxide layer 502. An oxide etchant is applied to structure 100, and the portions of the oxide layer 502 not covered by the hard mask 504 are etched to form microchannels 602 in the oxide layer 502.

[0039] Figure 6 A top view and a section view (AA) of the structure 100 after processing operations according to one or more embodiments of the present invention are depicted. Figure 6 As shown, after oxide etching is performed to form microchannels 602 in structure 100, hard mask 504 is removed (as shown in the image). Figure 5 As shown, this forms a first wafer 604 including a microchannel 602. As shown, the first wafer 604 also includes an oxide layer 102, a contact 202, a bottom terminal 402, an oxide layer 302, and the microchannel 602.

[0040] Figure 7 A top view and a section view (AA) of the structure 100 after processing operations according to one or more embodiments of the present invention are depicted. Figure 7 As shown, the complementary wafer 702 has been formed and is similar to Figure 6The first wafer 604 is shown. The complementary wafer 702 includes an oxide layer 704, contacts 708 for top terminals 710 of a two-terminal sensor to be formed, and an oxide layer 706. In one or more embodiments of the invention, the complementary wafer 702 is formed without elements corresponding to the microchannel 602 and includes top terminals 710 corresponding to each bottom terminal 402 of the sensor formed in the first wafer 604. Figure 7 As shown, the top terminal 710 of the complementary wafer 702 is aligned with the bottom terminal 402 of the first wafer 604. The complementary wafer 702 is bonded to the first wafer 604 to complete the formation of structure 100, thereby forming a microfluidic device. As shown, the oxide layer 706 of the complementary wafer 702 is bonded to the microchannel 602 of the first wafer 604. It should be understood that any known technique can be used to perform the bonding process. In a non-limiting example, the microfluidic device forms two sensors, each including a top terminal and a bottom terminal, which measure capacitance when fluid flows through the microchannel; however, it should be understood that any number of sensors can be included to obtain measurement results during operation.

[0041] Figure 8 A configuration 800 for monitoring multiphase flow within a cross-section of a microchannel is described according to one or more embodiments of the present invention. In this non-limiting example, the microchannel includes two sensors. Each sensor includes top and bottom terminals and is used to measure the capacitance of the fluid. Fluid movement can be tracked in the microfluidic device, and the fluid-fluid interface can be monitored. The first sensor 802 includes a first terminal 802A and a second terminal 802B, which respectively correspond to... Figure 7 The bottom terminal 402 and the top terminal 710. The second sensor 804 includes a first terminal 804A and a second terminal 804B. It should be understood that any number of sensors can be integrated into a microfluidic device to track multiphase fluid flow.

[0042] The distance L between the two sensors (capacitors) is known. During the fabrication of the microfluidic device, the distance L can be selected for the desired application. In this non-limiting example, the distance L is ~1 mm. Dividing the distance L between the sensors by the time difference between the detection of the fluid interface between the first sensor 802 and the second sensor 804 yields the average interfacial displacement velocity U of the fluid in the microchannel, i.e., the quality factor.

[0043] like Figure 8 As shown, the sensor (such as Figure 7 As shown, the sensors are embedded in the walls of the microchannels, and each sensor includes a top terminal and a bottom terminal. Furthermore, the microchannels include a first fluid (fluid 1) and a second fluid (fluid 2) forming a fluid interface.

[0044] Figure 8 Graphs of the responses of the first sensor 802 and the second sensor 804 are also shown. The graph represents capacitance on the Y-axis and time units on the X-axis. Graphs of the inlet and outlet responses are shown, detecting the fluid flowing in the microchannel, where the fluid-fluid interface provides the capacitance change. The first graph represents the response at time T. in The first graph represents the time when the capacitance change is detected by the first sensor. The second graph represents the time when the capacitance change is detected by the second sensor at time Tout.

[0045] Using time and distance L information, the interface displacement velocity U within the microchannel can be calculated. It should be understood that the sensor is coupled to a processor or computing unit (such as...) Figure 15 As shown below, the interface displacement velocity U can be calculated using the following equation:

[0046]

[0047] Figure 9 Another configuration of a system 900 for tracking multiphase flow in a microfluidic device according to one or more embodiments of the present invention is depicted. System 900 includes a series of sensors positioned at different locations x along the fluid flow direction. i Each sensor includes two terminals, a top terminal and a bottom terminal, and functions as a capacitor to detect capacitance as fluid passes through the terminals. The first sensor at position x1 includes terminals 902A and 902B, the second sensor at position x2 includes terminals 904A and 904B, the third sensor at position x3 includes terminals 906A and 906B, and the fourth sensor at position x4 includes terminals 908A and 908B.

[0048] The saturation (S) of the intruding fluid (fluid 1) can be obtained by calculating the fraction of the total length that the fluid-fluid interface has moved. The interface velocity (U) and saturation (S) can be calculated using equations 2 and 3 below, respectively:

[0049]

[0050]

[0051] Where T is time, X is the sensor position, L is the length of the microchannel; and i is the index of the first sensor; and j (j>i) is the index of the second sensor.

[0052] like Figure 9A series of graphs, as shown, illustrates the time it takes for each sensor 902, 904, 906, and 908 to detect changes in capacitance of the multiphase flow. By measuring the capacitance between the top and bottom terminals of each sensor as a function of time, the movement of the fluid-fluid interface within the channel can be tracked. A series of graphs shows the capacitance change detected by the first sensor 902, followed by the second sensor 904, the third sensor 906, and the fourth sensor 908. The saturation of the microchannel can be determined by analyzing portions or segments of the microchannel.

[0053] Figure 10 A different embodiment of the invention is shown, which includes a plurality of sensors 1, 2, 3, 4, 5, which are arranged in parallel on the microchannels of the device. Figure 10 As shown, the sensor's position on the microchannel is known and can be used to determine the shape of the fluid interface, as described below. Each sensor includes two terminals, a top terminal ( Figure 10 (shown in the image) and bottom terminal (not shown), and are used as capacitors to detect capacitance when fluid passes through the terminals.

[0054] By using, for example Figure 10 The structure shown can determine the shape of the fluid-fluid interface, which provides information about the wettability of the intruding fluid. If the innermost sensor 3 detects a capacitance change after the outermost sensors 1 and 5, then fluid 1 wets the surface (t3 > t2, t4 > t1, t5). If the innermost sensor 3 detects a capacitance change before the outermost sensors 1 and 5, then fluid 2 wets the surface (t3 < t2, t4 < t1, t5). By determining whether the innermost sensor (in this case, sensor 3) detects the fluid interface first or last, the wettability characteristics of the intruding fluid can be determined.

[0055] Figure 11 Another embodiment of the invention is illustrated, comprising a network 1100 of interconnected microchannels filled with at least two fluids (first fluid 1102, second fluid 1104) to maintain multiphase flow. As shown, multiple measurements can be obtained at different locations within the microchannel network. Each segment of the network 1100 may include a pair of sensors, such as sensors 1106 and 1108, to detect the inlet and outlet of fluid through the associated segment of the network 1100. Figure 12 Network 1200 of different embodiments of the present invention is described, wherein the relevant regions include not only a two-dimensional (xy) network of connected microchannels, but also vertically (z) stacked and connected bypasses through the vertical channels. Figure 12As shown, each segment of network 1200 may include a pair of sensors, such as sensors 1206 and 1208, to detect the inlet and outlet of fluid passing through the segment, wherein each sensor 1206 and 1208 detects the fluid interface between the first fluid 1202 and the second fluid 1204.

[0056] Figure 13 A flowchart illustrating a method 1300 for manufacturing a microfluidic device according to one or more embodiments of the present invention is described. The microfluidic device may include, for example: Figure 7 The apparatus shown, method 1300 begins at block 1302 and proceeds to block 1304, which provides a first wafer forming first terminals including a first sensor and a second sensor. Figure 6 As shown, the first terminal includes a contact 202 and a plate. Furthermore, the first wafer includes microchannels for a microfluidic device for conveying fluid.

[0057] Frame 1306 forms a second wafer including second terminals of a first sensor and a second sensor. For example... Figure 7 As shown, a complementary wafer 702 is formed, which includes a second terminal corresponding to the first terminal. The second terminal includes contacts and plates similar to those formed in the first wafer.

[0058] Box 1308 bonds the first wafer to the second wafer, wherein a first terminal in the first wafer is aligned with a second terminal in the second wafer. Method 1300 ends at box 1310. Method 1300 is not subject to... Figure 13 The limitations of the steps shown should be understood; different steps or different sequences of steps can be used to fabricate microfluidic devices.

[0059] Figure 14 A flowchart depicts a method 1400 for electrical tracking of multiphase flow in a microfluidic device. Method 1400 can be... Figure 7-10 Any microfluidic device shown and such as Figure 15 The processing system shown is executed. Method 1400 begins at block 1402 and proceeds to block 1404, which provides a method for receiving a first reading from a first sensor of the microfluidic device using a processor. The first reading represents the detection of fluid at the interface between the fluid and the first sensor. When the fluid interface between the first fluid and the second fluid passes the first sensor, the capacitance changes and is detected by the first sensor. The time when the first sensor detects the fluid can be recorded.

[0060] Box 1406 uses a processor to receive a second reading from a second sensor in the microfluidic device. This second reading represents the detection of fluid at the interface between the fluid and the second sensor, where the first sensor is located at a distance from the second sensor. As the fluid interface between the first and second fluids continues to flow through the microchannel, it passes through the second sensor. The second sensor measures changes in capacitance and can record the time of detection.

[0061] Block 1408 calculates the flow rate of the fluid in the microfluidic device based at least in part on the time difference between the detections of the first and second sensors and the distance between the first and second sensors. The (volume) velocity can be calculated by dividing the flow rate by the cross-sectional area of ​​the channel. In one or more embodiments of the invention, as referenced below… Figure 15 The processor described performs calculations. Calculations, such as those shown in Equation 1, can be performed to obtain the interface displacement rate. In other embodiments of the invention, multiple sensors can be arranged in parallel or series to obtain quality factors such as the wettability of the fluid or the saturation of the channel. The obtained calculations can be performed in real time to control fluid flow by providing signals to pumps, regulators, etc. Method 1400 ends at block 1410. Method 1400 is not limited to... Figure 14 The steps shown should be understood to be different steps or different sequences of steps used to perform tracking of the fluid interface in a microfluidic device.

[0062] refer to Figure 15 An embodiment of a processing system 1500 for implementing the teachings of this document is illustrated. In this embodiment, the processing system 1500 has one or more central processing units (processors) 101a, 101b, 101c, etc. (collectively or collectively referred to as processor 101). In one embodiment, each processor 101 may include a Reduced Instruction Set Computer (RISC) microprocessor. The processor 101 is coupled to system memory 114 and various other components via system bus 113. Read-only memory (ROM) 122 is coupled to system bus 113 and may include a Basic Input / Output System (BIOS) that controls certain basic functions of the processing system 1500.

[0063] Figure 15Input / output (I / O) adapter 107 and network adapter 126 coupled to system bus 113 are also shown. I / O adapter 107 may be a Small Computer System Interface (SCSI) adapter that communicates with hard disk 103 and / or tape storage device 105 or any other similar component. I / O adapter 107, hard disk 103, and tape storage device 105 are collectively referred to herein as mass storage device 124. Operating system 120 for execution on processing system 1500 may be stored in mass storage device 124. Network adapter 126 interconnects system bus 113 with external network 116, enabling processing system 1500 to communicate with other such systems. Screen (e.g., display monitor) 115 is connected to system bus 113 via display adapter 112, which may include a graphics adapter and video controller for improving performance in graphics-intensive applications. In one embodiment, adapters 107, 126, and 112 may be connected to one or more I / O buses that are connected to system bus 113 via an intermediate bus bridge (not shown). A suitable I / O bus for connecting peripheral devices such as hard disk controllers, network adapters, and graphics adapters typically includes common protocols such as Peripheral Component Interconnect (PCI). Additional input / output devices are shown connected to the system bus 113 via user interface adapter 108 and display adapter 112. Keyboard 109, mouse 110, and speaker 111 are all interconnected to the system bus 113 via user interface adapter 108, which may include, for example, a super I / O chip integrating multiple device adapters into a single integrated circuit.

[0064] In an exemplary embodiment, the processing system 1500 includes a graphics processing unit 130. The graphics processing unit 130 is a dedicated electronic circuit designed to manipulate and modify memory to accelerate the creation of a predetermined image in a frame buffer for output to a display. Typically, the graphics processing unit 130 is highly efficient in manipulating computer graphics and image processing and has a highly parallel architecture, making its algorithms more efficient than those of a general-purpose CPU for processing large blocks of data in parallel.

[0065] Therefore, as Figure 15 The processing system 1500 configured therein includes processing power in the form of a processor 101, storage capacity including system memory 114 and mass storage device 124, input devices such as a keyboard 109 and a mouse 110, and output capacity including a speaker 111 and a display 115. In one embodiment, a portion of the system memory 114 and the mass storage device 124 jointly store the operating system for coordination. Figure 15 The functions of the various components shown are illustrated.

[0066] This invention can be a system, method, and / or computer program product at any possible level of technical detail integration. The computer program product may include a computer-readable storage medium (or media) having computer-readable program instructions thereon for causing a processor to perform aspects of the invention.

[0067] Computer-readable storage media can be tangible devices capable of retaining and storing instructions for use by an instruction execution device. Computer-readable storage media can be, for example, but not limited to, electronic storage devices, magnetic storage devices, optical storage devices, electromagnetic storage devices, semiconductor storage devices, or any suitable combination of the foregoing. A non-exhaustive list of more specific examples of computer-readable storage media includes the following: portable computer disks, hard disks, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), static random access memory (SRAM), portable optical disc read-only memory (CD-ROM), digital multifunction disc (DVD), memory sticks, floppy disks, mechanical encoding devices such as punch cards or recessed structures with instructions recorded thereon, and any suitable combination of the foregoing. As used herein, computer-readable storage media should not be construed as transient signals themselves, such as radio waves or other freely propagating electromagnetic waves, electromagnetic waves propagating through waveguides or other transmission media (e.g., light pulses through fiber optic cables), or electrical signals transmitted through wires.

[0068] The computer-readable program instructions described herein can be downloaded from a computer-readable storage medium to a suitable computing / processing device, or via a network, such as the Internet, a local area network (LAN), a wide area network (WAN), and / or a wireless network, to an external computer or external storage device. The network may include copper cables, optical fibers, wireless transmission, routers, firewalls, switches, gateway computers, and / or edge servers. A network adapter card or network interface in each computing / processing device receives the computer-readable program instructions from the network and forwards them to a computer-readable storage medium within the respective computing / processing device.

[0069] Computer-readable program instructions used to perform the operations of this invention may be assembly instructions, instruction set architecture (ISA) instructions, machine instructions, machine-dependent instructions, microcode, firmware instructions, status setting data, integrated circuit configuration data, or source code or object code written in any combination of one or more programming languages ​​(including object-oriented programming languages ​​such as Smalltalk, C++, etc.) and procedural programming languages ​​(such as the "C" programming language or similar programming languages). The computer-readable program instructions may be executed entirely on the user's computer, partially on the user's computer, as a stand-alone software package, partially on the user's computer and partially on a remote computer, or entirely on a remote computer or server. In the latter case, the remote computer may be connected to the user's computer via any type of network, including a local area network (LAN) or a wide area network (WAN), or may be connected to an external computer (e.g., via the Internet using an Internet service provider). In some embodiments, to perform aspects of this invention, electronic circuits, including, for example, programmable logic circuits, field-programmable gate arrays (FPGAs), or programmable logic arrays (PLAs), may execute computer-readable program instructions to personalize the electronic circuits by utilizing the status information of the computer-readable program instructions.

[0070] Various aspects of the present invention are described herein with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer-readable program instructions.

[0071] These computer-readable program instructions may be provided to a processor of a general-purpose computer, a special-purpose computer, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions / actions specified in one or more blocks of a flowchart and / or block diagram. These computer-readable program instructions may also be stored in a computer-readable storage medium that can direct a computer, programmable data processing apparatus, and / or other devices to operate in a particular manner, such that the computer-readable storage medium in which the instructions are stored includes an article of writing comprising instructions for implementing aspects of the functions / actions specified in one or more blocks of a flowchart and / or block diagram.

[0072] Computer-readable program instructions may also be loaded onto a computer, other programmable data processing apparatus or other device to cause a series of operational steps to be performed on the computer, other programmable apparatus or other device to produce a computer-implemented process, such that the instructions, which execute on the computer, other programmable apparatus or other device, perform the functions / actions specified in one or more boxes of a flowchart and / or block diagram.

[0073] The flowcharts and block diagrams in the accompanying drawings illustrate the architecture, functionality, and operation of possible implementations of systems, methods, and computer program products according to various embodiments of the present invention. In this regard, each block in a flowchart or block diagram may represent a module, segment, or portion of instructions comprising one or more executable instructions for implementing a specified logical function. In some alternative embodiments, the functions indicated in the blocks may occur in a non-consecutive order as shown in the figures. For example, two blocks shown consecutively may actually be executed substantially simultaneously, or these blocks may sometimes be executed in reverse order, depending on the functions involved. It will also be noted that each block in the block diagrams and / or flowcharts, and combinations of blocks in the block diagrams and / or flowcharts, may be implemented by a dedicated hardware-based system that performs the specified function or action or executes a combination of dedicated hardware and computer instructions.

[0074] Various embodiments of the invention have been described for illustrative purposes, but are not intended to be exhaustive or limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope of the described embodiments. The terminology used herein has been chosen to best explain the principles of the embodiments, their practical application, or improvements to existing technologies in the market, or to enable others skilled in the art to understand the embodiments disclosed herein.

[0075] Compared to existing architectures, the techniques described herein do not require complex optical measurement equipment (high-resolution, high-sensitivity microscopes) to directly observe and evaluate fluid flow. Furthermore, the techniques described herein offer very high integration density (3D integration) and can be scaled down to the nanometer scale, and are compatible with standard semiconductor technology processes.

[0076] Various embodiments of the invention are described herein with reference to the accompanying drawings. Alternative embodiments may be devised without departing from the scope of the invention. Although various connections and positional relationships (e.g., above, below, adjacent, etc.) between elements are illustrated in the following description and drawings, those skilled in the art will recognize that many of the positional relationships described herein are orientation-independent, provided that the described functionality is maintained even if the orientation is changed. Unless otherwise stated, these connections and / or positional relationships may be direct or indirect, and the invention is not intended to be limited in this respect. Thus, coupling of entities may refer to direct or indirect coupling, and positional relationships between entities may be direct or indirect positional relationships. As an example of an indirect positional relationship, the description herein of forming layer "A" on layer "B" includes cases where one or more intermediate layers (e.g., layer "C") are between layer "A" and layer "B," provided that the relevant characteristics and functions of layer "A" and layer "B" are substantially not altered by the intermediate layers.

[0077] The following definitions and abbreviations are used to interpret the claims and specification. As used herein, the terms “comprising,” “including,” “having,” “containing,” or any other variations thereof are intended to cover a non-exclusive inclusion. For example, a composition, mixture, process, method, article, or apparatus that comprises a list of elements is not necessarily limited to those elements, but may include other elements not expressly listed or inherent to such compositions, mixtures, processes, methods, articles, or apparatus.

[0078] Additionally, the term "exemplary" is used herein to mean "serving as an example, instance, or illustration." Any embodiment or design described herein as "exemplary" is not necessarily to be construed as preferred or advantageous over other embodiments or designs. The terms "at least one" and "one or more" are understood to include any integer greater than or equal to one, i.e., one, two, three, four, etc. The term "multiple" should be understood to include any integer greater than or equal to two, i.e., two, three, four, five, etc. The term "connection" can include both indirect "connection" and direct "connection."

[0079] References to "an embodiment," "embodiment," "example embodiment," etc., in this specification indicate that the described embodiment may include a particular feature, structure, or characteristic; however, each embodiment may or may not include that particular feature, structure, or characteristic. Furthermore, these phrases do not necessarily refer to the same embodiment. Additionally, when a particular feature, structure, or characteristic is described in connection with an embodiment, it is believed that incorporating other embodiments to affect that feature, structure, or characteristic is within the knowledge of those skilled in the art, regardless of whether it is explicitly described.

[0080] For the purposes described below, the terms “upper,” “lower,” “right,” “left,” “vertical,” “horizontal,” “top,” “bottom,” and their derivatives shall apply to the described structures and methods, as oriented as shown in the accompanying drawings. The terms “cover,” “on top,” “positioned on top,” or “positioned on top” indicate that a first element, such as a first structure, is present on a second element, such as a second structure, wherein an intermediate element, such as an interface structure, may be present between the first and second elements. The term “direct contact” refers to the connection of the first element (e.g., the first structure) and the second element (e.g., the second structure) at the interface between the two elements without any intermediate conductive, insulating, or semiconductor layer.

[0081] For ease of description, spatial relative terms such as “below,” “above,” “over,” etc., may be used herein to describe the relationship between one element or feature and another, as shown in the accompanying drawings. It should be understood that spatial relative terms are intended to include different orientations of the device in use or operation other than those shown in the figures. For example, if the device in the figures were flipped, an element described as “below” or “under” other elements or features would be oriented as “above” other elements or features. Thus, the term “below” can include both above and below orientations. The device may be oriented in other ways (rotated 90 degrees or in other orientations), and the spatial relative descriptions used herein shall be interpreted accordingly.

[0082] The phrase “to” implies selectivity. For example, “the first element is selective to the second element” means that the first element can be etched while the second element can act as an etch stop layer.

[0083] The terms “about,” “substantially,” “approximately,” and variations thereof are intended to include a degree of error associated with a measurement of a specific quantity based on the equipment available at the time of filing this application. For example, “about” may include a range of ±8%, 5%, or 2% of a given value.

[0084] The term “conformal” (e.g., conformal layer) means that the thickness of a layer is substantially the same on all surfaces, or the thickness variation is less than 15% of the nominal thickness of the layer.

[0085] As previously mentioned, for the sake of brevity, conventional techniques related to the manufacture of semiconductor devices and integrated circuits (ICs) may or may not be described in detail herein. However, as background, a more general description of semiconductor device manufacturing processes that can be used to implement one or more embodiments of the present invention will now be provided. Although specific manufacturing operations used in implementing one or more embodiments of the present invention may be individually known, the combination of described operations and / or the resulting structure of the invention is unique. Thus, the unique combination of operations described in conjunction with the manufacture of semiconductor devices according to the present invention utilizes a variety of individually known physical and chemical processes performed on a semiconductor (e.g., silicon) substrate, some of which are described in the following paragraphs.

[0086] Generally, the various processes used to form microchips that will be packaged into ICs are categorized into four general types: film deposition, removal / etching, semiconductor doping, and patterning / photolithography. Deposition is any process that grows, coats, or otherwise transfers material onto a wafer. Available techniques include physical vapor deposition (PVD), chemical vapor deposition (CVD), electrochemical deposition (ECD), molecular beam epitaxy (MBE), and more recently, atomic layer deposition (ALD). Removal / etching is any process that removes material from a wafer. Examples include etching processes (wet or dry) and chemical mechanical planarization (CMP). Semiconductor doping alters electrical properties by doping, for example, transistor sources and drains, typically through diffusion and / or ion implantation. These doping processes are followed by furnace annealing or rapid thermal annealing (RTA). Annealing is used to activate the implanted dopant. Films of conductors (e.g., polysilicon, aluminum, copper, etc.) and insulators (e.g., various forms of silicon dioxide, silicon nitride, etc.) are used to connect and isolate transistors and their components. Selective doping of individual regions on a semiconductor substrate allows the substrate's conductivity to change with the application of voltage. By forming the structures of these various components, millions of transistors can be built and wired together to form the complex circuitry of modern microelectronic devices. Semiconductor lithography is the process of forming a three-dimensional relief image or pattern on a semiconductor substrate so that the pattern can be subsequently transferred onto the substrate. In semiconductor lithography, the pattern is formed from a photosensitive polymer called a photoresist. To build the numerous wirings of the millions of transistors that make up the complex structure of the transistors and the interconnecting circuitry, the photolithography and etching pattern transfer steps are repeated multiple times. Each pattern printed on the wafer is aligned with the previously formed pattern, and conductors, insulators, and selectively doped regions are slowly deposited to form the final device.

[0087] The flowcharts and block diagrams in the accompanying drawings illustrate possible implementations of manufacturing and / or operating methods according to various embodiments of the invention. Various functions / operations of the method are represented by boxes in the flowcharts. In some alternative embodiments, the functions indicated in the boxes may occur in a different order than indicated in the figures. For example, two boxes shown consecutively may actually be performed substantially simultaneously, or these boxes may sometimes be performed in reverse order, depending on the functions involved.

[0088] Various embodiments of the invention have been described for illustrative purposes, but are not intended to be exhaustive or limited to the described embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope of the described embodiments. The terminology used herein has been chosen to best explain the principles of the embodiments, their practical application, or improvements to existing technologies on the market, or to enable others skilled in the art to understand the embodiments described herein.

Claims

1. A computer-implemented method for tracking fluids in a microfluidic device, the computer-implemented method comprising: The processor receives a first reading from a first sensor in the microfluidic device, the first reading representing the detection of fluid at the interface between the fluid and the first sensor; The processor receives a second reading from a second sensor of the microfluidic device, the second reading representing the detection of the fluid at the interface between the fluid and the second sensor, wherein the first sensor is located at a distance from the second sensor; as well as The processor calculates the flow rate of the fluid in the microfluidic device based at least in part on the time difference between the detections of the first and second sensors and the distance between the first and second sensors. The method further includes using a first additional sensor arranged parallel to the channel in the microfluidic device to detect the central portion and the edge portion of the fluid to determine the wettability of the fluid.

2. The computer-implemented method according to claim 1, wherein, The time difference between the detection at the first sensor and the detection at the second sensor is measured.

3. The computer-implemented method according to claim 1, wherein the first sensor and the second sensor are embedded in the microfluidic device.

4. The computer-implemented method of claim 1 further includes using a second additional sensor to detect the fluid interface, wherein the first sensor, the second sensor, and the second additional sensor are arranged in series.

5. The computer-implemented method of claim 4, further comprising determining the channel saturation by performing detection by the first sensor, the second sensor, and the second additional sensor, which are positioned in series along the direction of fluid flow in the channel of the microfluidic device.

6. The computer-implemented method according to any one of claims 1-5, wherein the first sensor and the second sensor are configured to detect capacitance changes caused by the fluid flowing in the microfluidic device.

7. A system for tracking multiphase flow in a microfluidic device, the system comprising: processor; A memory coupled to the processor, the processor being configured to: A first reading is received from a first sensor of the microfluidic device, the first reading representing the detection of fluid at the interface between the fluid and the first sensor; A second reading is received from a second sensor in the microfluidic device, the second reading representing the detection of fluid at the interface between the fluid and the second sensor; as well as The flow rate of the fluid in the microfluidic device is calculated at least in part based on the time difference between the detections of the first and second sensors and the distance between the first and second sensors. The processor is further configured to use a first additional sensor arranged parallel to the channel in the microfluidic device to detect the central portion and the edge portion of the fluid to determine the wettability of the fluid.

8. The system according to claim 7, wherein, The time difference is measured between the detection at the first sensor and the detection at the second sensor.

9. The system of claim 7, wherein the first sensor and the second sensor are embedded in the microfluidic device.

10. The system of claim 7, wherein the processor is further configured to use a second additional sensor to detect the fluid interface, wherein the first sensor, the second sensor, and the second additional sensor are arranged in series.

11. The system of claim 10, wherein the processor is further configured to determine the channel saturation by performing detection by the first sensor, the second sensor, and the second additional sensor, which are located in series along the direction of fluid flow in the channel of the microfluidic device.

12. The system of claim 7, wherein the processor is further configured to tune the frequencies of the first sensor and the second sensor to detect the fluid interface, at least in part based on the fluid type in the microfluidic device.

13. The system according to any one of claims 7-12, wherein the first sensor and the second sensor are configured to detect capacitance changes caused by the fluid flowing in the microfluidic device.

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