Inductive biosensor integrated on TGV and manufacturing method thereof

Abstract

The invention discloses an inductive biosensor integrated on a TGV and a manufacturing method thereof. The inductive biosensor comprises a first substrate, a second substrate and a conductive material. The first substrate and the second substrate are oppositely arranged along a first direction, the first substrate is respectively provided with a first through hole and a second through hole which penetrate through the first substrate, and the first through hole and the second through hole are filled with a conductive material to form a spiral conductive path surrounding the first direction so as to form an inductance element. The device is further provided with a micro-channel, the surface, facing the second substrate, of the first substrate and the surface, facing the first substrate, of the second substrate are configured to be inner walls of the micro-channel, the micro-channel is spaced from the first through hole and the second through hole in the direction perpendicular to the first direction, the micro-channel is suitable for containing a to-be-detected medium and magnetic beads, and the inductance element can generate a magnetic field. Therefore, the magnetic beads can be sensed and inductance change can be generated. The inductive biosensor integrated on the TGV is small in size, high in sensitivity, high in aspect ratio, high in stability and low in cost.

Description

Technical Field

[0001] This invention relates to the field of biosensing technology, and in particular to an inductive biosensor integrated on a TGV and its fabrication method. Background Technology

[0002] Inductive TGV chips utilize coils to sense signals from magnetic beads, enabling rapid detection of target molecules in turbid samples such as blood and saliva without fluorescent labeling, making them ideal for home health checkups and bedside diagnostics. Their working principle involves an alternating current passing through a coil to generate a magnetic field. When a magnetic bead coated with antibodies or nucleic acid probes is captured by the target molecule and enters the magnetic field, the magnetization disturbance of the bead alters the coil's inductance. For example, in a liquid phase, the magnetic bead coated with antibodies / nucleic acid probes can specifically bind to the target molecule (protein, nucleic acid, or intact virus) in the sample, forming a complex. This complex flows into the chip with the liquid, and an alternating current is applied to the coil to establish a high-frequency magnetic field. The magnetic bead is pulled to the coil surface by a gradient force, and the magnetization disturbance of the bead is directly superimposed on the magnetic flux of the coil, causing a measurable inductance drift, which can then be used to calculate the concentration of the target molecule. The entire process does not rely on large optical systems and can provide results within minutes, thus being regarded by the industry as a key technological path for promoting decentralized and real-time medical testing.

[0003] However, most existing chips are fabricated with planar coils or through-silicon vias (TSVs) on a silicon substrate. Planar structures have weak magnetic field gradients, resulting in extremely low induction signals for nanobeads, making it difficult to reach the detection limits required in clinical applications. Increasing the number of turns or using high aspect ratio TSVs requires depositing multiple layers of barrier and seed layers, as well as repeated deep-hole etching, copper plating, and chemical mechanical polishing, resulting in complex processes, low yields, and significantly increased costs per chip. Summary of the Invention

[0004] The main objective of this invention is to propose an inductive biosensor integrated on a TGV and its fabrication method. The inductive biosensor integrated on a TGV in this application is small in size, highly sensitive, has a high aspect ratio, strong stability, and low cost.

[0005] To achieve the above objectives, some embodiments of the present invention propose an inductive biosensor integrated on a TGV, comprising a first substrate and a second substrate disposed opposite to each other along a first direction and a conductive material. The first substrate has a first through-hole extending toward the second substrate from the side of the first substrate away from the second substrate, and the side of the first substrate facing the second substrate is sealed. The second substrate has a second through-hole extending toward the first substrate from the side of the second substrate away from the first substrate, and the side of the second substrate facing the first substrate is sealed. Both the first through-hole and the second through-hole are filled with conductive material. The conductive materials in the first and second through holes together form a spiral conductive path around the first direction to constitute an inductor element. The inductive biosensor integrated on the TGV also features a microchannel. The surfaces of the first substrate facing the second substrate and the second substrate facing the first substrate are both configured as the inner walls of the microchannel. The microchannel is suitable for accommodating the test medium and the magnetic bead. The inductive element can generate a magnetic field to sense the magnetic bead and generate an inductance change.

[0006] In some embodiments, the first through-hole and the second through-hole are alternately distributed in a plane perpendicular to the first direction, and the inclination directions of the line connecting the ends of the conductive material in adjacent first through-holes and the line connecting the ends of the conductive material in adjacent second through-holes are opposite to form a spiral conductive path.

[0007] In some embodiments, the diameter of the first through hole and / or the second through hole ranges from 0.4 to 1 mm; and / or, the aspect ratio of the first through hole and / or the second through hole is less than or equal to 15:1.

[0008] In some embodiments, the conductive material includes copper, a copper layer is deposited on the surface of a first substrate, and a copper layer is deposited on the surface of a second substrate; and / or, The first substrate includes a glass substrate, and the second substrate includes a glass substrate.

[0009] In some embodiments, the surface of the first substrate is recessed toward the surface of the second substrate to form a first groove, and the surface of the second substrate is recessed toward the surface of the first substrate to form a second groove. The first substrate is attached to the second substrate so that the first groove and the second groove together define a microchannel.

[0010] In some embodiments, an adhesive layer is provided between the first substrate and the second substrate to seal the microchannels and bond the first substrate and the second substrate.

[0011] In some embodiments, the inductive biosensor integrated on the TGV further includes: The differential readout circuit is coupled to the inductive element and is used to convert changes in inductance into voltage signals. The wireless module, coupled to the differential readout circuit, is used to send the detection results to an external terminal.

[0012] A second aspect of the present invention provides a method for fabricating an inductive biosensor integrated on a TGV according to any of the above claims, the method comprising: A first substrate and a second substrate are provided; A first through-hole is formed on a first substrate, and a second through-hole is formed on a second substrate; Conductive material is filled into the first and second through holes to form a spiral conductive path; A microchannel is formed between the first substrate and the second substrate, and a spiral conductive path surrounds at least a portion of the microchannel.

[0013] In some embodiments, the step of forming a first through-hole on a first substrate and forming a second through-hole on a second substrate includes: The first through-hole and / or the second through-hole are formed by laser-induced wet etching; Conductive material is directly filled into the through-hole using a barrier-free electroplating process.

[0014] In some embodiments, after the step of forming a microchannel between the first substrate and the second substrate, and the spiral conductive path surrounding at least a portion of the microchannel, the fabrication method further includes: Connect the inductor to the differential readout circuit; The sensor is encapsulated so that the microchannel retains only the inlet and outlet.

[0015] According to the above embodiments, the beneficial effects of the present invention are: The inductive biosensor integrated on the TGV of this application includes a first substrate, a second substrate, and a conductive material. The first substrate and the second substrate are disposed opposite each other along a first direction. The first substrate is respectively provided with a first through-hole and a second through-hole. Both the first through-hole and the second through-hole are filled with conductive material to form a spiral conductive path around the first direction, thereby constituting an inductive element. This application also includes a microchannel. The surface of the first substrate facing the second substrate and the surface of the second substrate facing the first substrate are both configured as the inner wall of the microchannel. Along a direction perpendicular to the first direction, the microchannel is spaced apart from the first through-hole and the second through-hole, respectively. The microchannel is suitable for accommodating the test medium and a magnetic bead. The inductive element can generate a magnetic field to sense the magnetic bead and generate an inductance change.

[0016] Specifically, this invention utilizes a three-dimensional integration method where two substrates arranged opposite each other along a first direction, each substrate having through-holes, and conductive material filled within the through-holes to create a spiral conductive path. This embeds the inductor coil within the microchannel wall at a macroscopic level, ensuring the magnetic field generation area and sample area are highly aligned in three-dimensional space. Since the spiral path is formed by the end-to-end connection of conductive segments located on the upper and lower substrates via through-holes, the number of coil turns and their arrangement can be arbitrarily expanded within the substrate plane without increasing the chip area, thus balancing high sensitivity and miniaturization. The inner wall of the microchannel is defined by the opposing surfaces of the two substrates, eliminating the need for additional pipework. This simplifies the interlayer alignment process and eliminates sample residue issues associated with traditional adhesive pipes, ensuring the magnetic bead remains close to the sensitive area of ​​the inductor during flow, significantly improving capture probability and signal conversion efficiency. Overall, this application compresses the three major functions of inductance generation, magnetic field application, and magnetic bead sensing into a single spatial dimension, enhancing the magnetic field gradient, reducing the area of ​​the inductive biosensor integrated on the TGV, and lowering costs. This achieves minimalist integration of the sensor core area, facilitating mass production.

[0017] In summary, this application is small in size, highly sensitive, has a high aspect ratio, strong stability, and low cost.

[0018] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0020] Figure 1 This is an exploded structural diagram of an inductive biosensor integrated on a TGV in one embodiment of the present invention. Figure 2 This is a flowchart of a manufacturing method in one embodiment of the present invention.

[0021] Explanation of icon numbers: First substrate 100; first through hole 110; first groove 120; Second substrate 200; second through hole 210; second groove 220.

[0022] The realization of the objective, functional features and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0023] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0024] It should be noted that if the embodiments of the present invention involve directional indicators (such as up, down, left, right, front, back, etc.), the directional indicators are only used to explain the relative positional relationship and movement of the components in a specific posture. If the specific posture changes, the directional indicators will also change accordingly.

[0025] Furthermore, if the embodiments of this invention involve descriptions such as "first" or "second," these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the use of "and / or," "and / or," or "and / or" throughout the text implies three parallel solutions. For example, "A and / or B" includes solution A, solution B, or a solution where both A and B are satisfied simultaneously. Furthermore, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by this invention.

[0026] In related technologies, traditional silicon-based architectures have created a systemic contradiction between sensitivity, reliability, and cost: First, the magnetic field gradient generated by planar coils or low aspect ratio silicon TSVs (<10:1) is "significantly insufficient," resulting in a sensing signal of only "approximately microvolts" for 10nm superparamagnetic particles, making it difficult to stably break through the fg / μL level detection limit. If sensitivity is forcibly improved by increasing the number of coil turns or height, it is necessary to rely on high aspect ratio silicon TSVs (>10:1) with "complex processes and low yields," such as Bosch deep silicon etching, multilayer barrier / seed layers, and deep hole plating, which is widely reported in the industry as significantly increasing the cost per wafer. Second, the corrosion rate of silicon substrates in bodily fluid environments with pH>10 is "relatively fast," and the large difference in thermal expansion coefficients between silicon, metal, and oxide leads to "non-negligible" resistance drift after thermal cycling, posing a challenge to long-term signal stability. Furthermore, silicon TSVs require multiple high-cost processes, including the addition of insulating layers, barrier layers, seed layers, and CMP. Industry estimates suggest that these processes account for nearly or more than 40% of the total cost of the sensor, making them a major obstacle to large-scale, one-time applications.

[0027] The following is for reference. Figure 1 and Figure 2 This describes an inductive biosensor integrated on a TGV according to an embodiment of the present invention, and its fabrication method. (Refer to...) Figure 1 An embodiment of the first aspect of this application proposes an inductive biosensor integrated on a TGV, comprising a first substrate 100, a second substrate 200, and a conductive material. The first substrate 100 and the second substrate 200 are disposed opposite each other along a first direction. The first substrate 100 is respectively provided with a first through-hole 110 and a second through-hole 210 penetrating through itself. Both the first through-hole 110 and the second through-hole 210 are filled with conductive material to form a spiral conductive path surrounding the first direction, thereby constituting an inductive element. This application also includes microchannels. The surfaces of the first substrate 100 facing the second substrate 200 and the second substrate 200 facing the first substrate 100 are both configured as the inner walls of the microchannels. Along a direction perpendicular to the first direction, the microchannels are spaced apart from the first through-hole 110 and the second through-hole 210, respectively. The microchannels are adapted to accommodate a test medium and a magnetic bead. The inductive element can generate a magnetic field to sense the magnetic bead and generate an inductance change.

[0028] Specifically, this invention utilizes a three-dimensional integration method where two substrates arranged opposite each other along a first direction, each substrate having through-holes, and conductive material filled within the through-holes to create a spiral conductive path. This embeds the inductor coil within the microchannel wall at a macroscopic level, ensuring the magnetic field generation area and sample area are highly aligned in three-dimensional space. Since the spiral path is formed by the end-to-end connection of conductive segments located on the upper and lower substrates via through-holes, the number of coil turns and their arrangement can be arbitrarily expanded within the substrate plane without increasing the chip area, thus balancing high sensitivity and miniaturization. The inner wall of the microchannel is defined by the opposing surfaces of the two substrates, eliminating the need for additional pipework. This simplifies the interlayer alignment process and eliminates sample residue issues associated with traditional adhesive pipes, ensuring the magnetic bead remains close to the sensitive area of ​​the inductor during flow, significantly improving capture probability and signal conversion efficiency. Overall, this application compresses the three major functions of inductance generation, magnetic field application, and magnetic bead sensing into a single spatial dimension, enhancing the magnetic field gradient, reducing the area of ​​the inductive biosensor integrated on the TGV, and lowering costs. This achieves minimalist integration of the sensor core area, facilitating mass production.

[0029] In summary, this application is small in size, highly sensitive, has a high aspect ratio, strong stability, and low cost.

[0030] Reference Figure 1In some embodiments, the first through-hole 110 and the second through-hole 210 are alternately distributed in a plane perpendicular to the first direction, and the inclination directions of the connecting lines of the ends of the conductive material in adjacent first through-holes 110 and adjacent second through-holes 210 are opposite to form a spiral conductive path. By arranging the first through-holes 110 and the second through-holes 210 alternately in a plane perpendicular to the first direction and making the connecting lines of the ends of adjacent conductive materials tilt in opposite directions, a continuous and smooth spiral conductive path can be naturally spliced ​​out macroscopically. This design utilizes the two-dimensional extension space of the first substrate 100 and the second substrate 200 themselves, making each hole segment part of the coil turn, eliminating the need for cross-layer jumpers or additional structures required by traditional three-dimensional winding, thereby reducing resistance and improving quality. The reverse tilting design causes the current to form a tangential component around the central axis when transferring between adjacent holes, effectively strengthening the axial concentration of the magnetic field, preventing the magnetic lines of force from diffusing outward, and thus enhancing the near-field coupling efficiency of the magnetic beads in the microchannel. Because the path is continuous, the excitation current can be evenly distributed to each turn, reducing the risk of localized heating and electromigration, and extending the sensor's lifespan. Meanwhile, the alternating array of vias has minimal impact on the overall rigidity of the substrate, releasing internal stress during thermal cycling or mechanical bending, reducing interfacial slippage between the conductive material and the insulating substrate, and maintaining long-term stability of the inductance value.

[0031] Reference Figure 1In some embodiments, the diameter of the first through-hole 110 and / or the second through-hole 210 ranges from 0.02 to 0.09 mm, for example, the diameter ranges of the first through-hole 110 and / or the second through-hole 210 are 0.02 mm, 0.04 mm, 0.06 mm, and 0.09 mm. In some embodiments, the aspect ratio of the first through-hole 110 and / or the second through-hole 210 is less than or equal to 15:1, for example, the aspect ratio of the first through-hole 110 and / or the second through-hole 210 is 15:1, 14:1, and 13:1. Specifically, by reasonably limiting the diameter and aspect ratio of the first through-hole 110 and the second through-hole 210, the conductive material can remain uniform and dense during the filling process, avoiding uneven resistance distribution caused by tilted hole walls or bottom voids, thereby ensuring the overall conductivity and magnetic field consistency of the spiral conductive path. Simultaneously, this size range balances the mechanical strength of the insulating substrate with the spatial layout of the microchannels, preventing weakening of substrate rigidity or damage to microchannel sealing due to excessively large apertures, while also avoiding the filling difficulties and process fluctuation risks associated with excessively small apertures. Furthermore, controlling the upper limit of the aspect ratio effectively suppresses stress concentration issues caused by thermal cycling or external forces in high aspect ratio structures, reducing interface separation or microcracks between the conductive material and the insulating substrate due to expansion differences, thus improving the structural reliability and inductive stability of the sensor during long-term use. This size design provides sufficient process windows during manufacturing, enabling stable implementation of steps such as laser-induced etching, wet etching, and barrier-free plating, reducing stringent requirements on equipment precision and environmental conditions, and providing higher yields and lower cost margins for mass production. In summary, this parameter range achieves a balance between performance, reliability, and manufacturing cost, and facilitates sensor miniaturization.

[0032] Reference Figure 1In some embodiments, the conductive material includes copper, the first substrate 100 includes a glass substrate, and the second substrate 200 includes a glass substrate. Choosing copper as the conductive material and using glass substrates to construct the first substrate 100 and the second substrate 200 achieves a synergistic improvement in both high sensitivity and long-term reliability. Specifically, copper has extremely low resistivity and excellent electromigration tolerance, enabling the helical conductive path to generate a stronger magnetic field under the same excitation conditions, while reducing its own power consumption and heat generation, providing a stable and uniform magnetization environment for the magnetic beads within the microchannels. Glass substrates have significant advantages in chemical inertness, thermal matching, and mechanical stability. They exhibit almost no corrosion over a wide range of acids and alkalis, effectively resisting chemical erosion from bodily fluids or reagents, ensuring that the sensor maintains structural integrity and constant electrical performance even in complex biological samples. The thermal expansion coefficients of glass and copper are similar, which can significantly reduce interfacial stress caused by expansion differences during thermal cycling or high-temperature sterilization, reducing the risk of conductive layer peeling, cracking, or resistance drift, thereby maintaining long-term consistency in inductance values. Furthermore, high-precision vias can be formed in a single laser-induced wet etching process on the glass substrate, eliminating the need for multiple barrier and seed layers required in traditional silicon-based solutions. This allows for direct copper filling, simplifying the process, reducing costs, and avoiding parasitic resistance and capacitance introduced by additional interfaces. The combination of copper and glass substrates achieves high magnetic field output while endowing the sensor with excellent chemical stability, thermal stability, and manufacturability, thus balancing the performance and cost of inductive biosensors integrated on TGVs.

[0033] Reference Figure 1In some embodiments, the surface of the first substrate 100 facing the second substrate 200 is recessed to form a first groove 120, and the surface of the second substrate 200 facing the first substrate 100 is recessed to form a second groove 220. The first substrate 100 is bonded to the second substrate 200 so that the first groove 120 and the second groove 220 together define a microchannel. By providing the first groove 120 and the second groove 220 on the opposing surfaces of the first substrate 100 and the second substrate 200 respectively, and by bonding the two substrates together to enclose the microchannel, the flow path is directly defined within the substrate body, eliminating the need for additional insertion or bonding of tubing in traditional solutions, thus simplifying the assembly process. Since the groove is integrally formed with the substrate, the inner wall is smooth and continuous without any dead corners, making it less likely for samples to stagnate or accumulate bubbles during flow, effectively reducing residual volume and the risk of cross-contamination. At the same time, the integrated wall structure eliminates multi-layer material interfaces, preventing peeling or misalignment during thermal cycling or mechanical bending, thus enhancing overall sealing reliability. This design also allows the three-dimensional shape, depth, and orientation of the microchannels to be defined in a single step via etching or machining. It offers a wide process window, good repeatability, low equipment precision requirements, and facilitates large-area mass production. Utilizing the substrate's own thickness as mechanical support, the flow channel area can withstand pressure changes during external packaging and operation without additional thickening or reinforcement, maintaining structural integrity. In summary, this design improves sensor integration while ensuring both accurate fluid control and long-term stability.

[0034] Reference Figure 1 In some embodiments, an adhesive layer is provided between the first substrate 100 and the second substrate 200 to seal the microchannels and bond the first substrate 100 and the second substrate 200. By introducing an adhesive layer between the first substrate 100 and the second substrate 200, it is specifically designed to firmly bond the first substrate 100 and the second substrate 200 while simultaneously achieving circumferential sealing of the microchannels. Since the confined groove structure itself only provides the channel outline, gaps still exist at its edges. The adhesive layer can generate micro-flow under mild pressure, filling these gaps to form a continuous, seamless sealing band, effectively preventing liquid side leakage or gas infiltration, avoiding sample loss and external contamination. The adhesive layer also acts as a stress buffer, absorbing some deformation under thermal expansion differences or external impacts, reducing the risk of microcracks caused by direct rigid contact between substrates, thereby maintaining the integrity of the channel walls and the stability of the inductor. In some embodiments, the adhesive layer can be made of a material that wets well with glass and has a low curing temperature, achieving rapid curing without affecting the conductive structure within the via, simplifying the encapsulation process. By introducing an adhesive layer, the sensor can achieve long-term reliable liquid-sealed packaging without adding complex mechanical locking or high-temperature bonding equipment.

[0035] Reference Figure 1In some embodiments, the inductive biosensor integrated on the TGV also includes a differential readout circuit and a wireless module. The differential readout circuit is coupled to the inductive element and is used to convert inductance changes into voltage signals. The wireless module is coupled to the differential readout circuit and is used to send the detection results to an external terminal. Through the differential readout circuit and the wireless module, this application forms a complete signal chain of self-sensing, self-conversion, and self-transmission, upgrading the sensor from a passive element to an independently outputting intelligent node. The differential readout circuit has a natural ability to suppress common-mode interference, and can still extract pure microvolt-level changes in complex electromagnetic environments or power fluctuation conditions, avoiding misjudgments caused by drift in traditional single-ended reading. At the same time, the high input impedance characteristic of the differential readout circuit does not require additional inductive elements, maintaining the original quality factor and magnetic field strength, ensuring that the sensing sensitivity is not sacrificed. The converted voltage signal is sent to the wireless module and uploaded in real time via the radio frequency link, without the need for external leads or contact interfaces. This eliminates parasitic parameters introduced by wires and removes the dependence on spatial wiring in the application scenario, achieving a plug-and-play effect. Furthermore, in some embodiments, the wireless transmission of this application allows multiple sensors to access the same terminal in parallel, providing a hardware foundation for high-throughput screening or distributed monitoring. Once the data is no longer locally available, it can be further combined with cloud algorithms for trend analysis and remote diagnosis, improving detection efficiency and medical response speed. With this design, this application enables the amplification, stabilization, and remote presentation of minute inductance changes, possessing information capabilities previously only available in large-scale equipment.

[0036] Reference Figure 2 A second aspect of the present invention provides a method for fabricating an inductive biosensor integrated on a TGV according to any of the above claims. The method includes: S101: Provide a first substrate 100 and a second substrate 200; S103: A first through-hole 110 is formed on the first substrate 100, and a second through-hole 210 is formed on the second substrate 200; S105: The first through hole 110 and the second through hole 210 are filled with conductive material to form a spiral conductive path; S107: A microchannel is formed between the first substrate 100 and the second substrate 200, and a spiral conductive path surrounds at least a portion of the microchannel.

[0037] The manufacturing method provided by this invention breaks down the complex three-dimensional inductor structure into sequentially executable processes, reducing manufacturing difficulty and equipment requirements. In step S101, only two flat insulating substrates are needed to begin, eliminating the need for pre-laden multilayer films, thus saving on the accumulation of alignment errors and investment in high-temperature bonding equipment, laying the foundation for low-cost mass production. Step S103 forms through-holes through single-sided processing, retaining an intact material layer at the bottom of the hole. This naturally forms the sealed bottom wall of the subsequent microchannels, avoiding the additional sealing process caused by through-holes, and reducing the decrease in mechanical strength caused by double-sided openings. The through-hole contour can be completed in one step by laser induction or wet etching, and the depth and diameter can be precisely controlled under single-sided exposure, resulting in a wide process window and good repeatability. Step S105 directly fills the through-hole with conductive material. Due to the intact hole wall, the electroplating solution is confined to flow within the hole, forming dense, low-defect conductive pillars. The conductive path is integrated with the substrate, eliminating the support skeleton required by traditional wire winding or patch mounting, reducing resistance and parasitic inductance, and ensuring magnetic field strength. Step S107 involves simultaneously creating microchannels during the bonding of the two substrates. The channel shape is defined in one step by the groove depth and contour, eliminating the need for subsequent machining or bonding, thus avoiding dead corners and seams. Simultaneously, the spiral conductive path naturally surrounds the outside of the channel, ensuring that the region of maximum magnetic field gradient highly overlaps with the liquid channel, improving sensing efficiency. The entire process requires only single-sided exposure, conventional electroplating, and standard alignment equipment, avoiding high-cost steps such as high aspect ratio etching, multi-layer alignment, and high-temperature bonding, thereby reducing process chain complexity and production cycle time.

[0038] In some embodiments, the step of forming a first through-hole 110 on the first substrate 100 and a second through-hole 210 on the second substrate 200 includes: S201: The first through hole 110 and / or the second through hole 210 are formed by laser-induced wet etching; S203: Conductive material is directly filled into the through hole through a barrier-free electroplating process.

[0039] Step S201 uses laser-induced wet etching to form the first through-hole 110 and the second through-hole 210 in one step: the laser induces local modification on the glass surface according to a preset pattern, and the subsequent wet etching rapidly advances along the modified area to accurately excavate the cavity; this process does not require photoresist coating, exposure and development, and pattern transformation only requires adjusting the laser scanning trajectory, which saves mask manufacturing costs and shortens the iteration cycle. At the same time, the etching depth is jointly controlled by laser energy and immersion time, which can flexibly obtain hole bottoms of different thicknesses, providing a complete substrate for subsequent sealing. Step S203 uses barrier-free electroplating to directly fill the through-hole with conductive material: the glass surface has catalytic ability after short-term activation treatment, eliminating the need for traditional titanium-copper composite barrier layers and seed layers, reducing high-vacuum deposition processes and material consumption. The electroplating solution only forms a uniform current field in the hole, and copper densely fills from bottom to top, eliminating the risk of breakage caused by an excessively thin barrier layer and void defects caused by uneven seed layer, thereby obtaining a conductive pillar with low resistance and high mechanical strength. Meanwhile, eliminating the barrier layer reduces thermal expansion mismatch and interfacial stress, making it less prone to microcracks during thermal cycling or mechanical bending, thus ensuring long-term stability of the inductance value. The synergy between laser etching and barrier-free electroplating allows high aspect ratio vias to be completed with high quality at room temperature and pressure, balancing precision, efficiency, and economy.

[0040] In some embodiments, after the step of forming a microchannel between the first substrate 100 and the second substrate 200, and the spiral conductive path surrounding at least a portion of the microchannel, the fabrication method further includes: S301: Electrically connect the inductor to the differential readout circuit; S303: The sensor is encapsulated so that the microchannel retains only the inlet and outlet.

[0041] Step S301 involves using metal bonding or conductive adhesive to guide the copper pillar ends of the through-hole to external pads, which are then connected to the differential amplifier chip. The differential structure instantly cancels common-mode interference, retaining only the microvolt-level differential signal caused by the ferrite bead, achieving high signal-to-noise ratio conversion and avoiding the burden of subsequent digital processing. Step S303 uses a low-temperature epoxy or thermoplastic film to cover the entire area except for the flow channel port, forming a seamless sidewall after curing. This effectively confines the liquid within the serpentine channel, preventing side leakage and contamination of external circuits. It also provides mechanical and chemical protection for inductors, pads, and wires, resisting sweat, cleaning fluids, or scratches during daily use. The encapsulation layer thickness is controllable, does not affect magnetic field penetration, and its elastic modulus is lower than that of glass, absorbing interface stress caused by thermal expansion and contraction, reducing the risk of conductive pillar fatigue. This design sequentially completes signal link closure and environmental isolation, enabling the chip to be read directly from a single drop of blood, ensuring both detection accuracy and low cost.

[0042] Below, refer to Figure 1 and Figure 2This application systematically describes an inductive biosensor integrated on a TGV and its fabrication method, using one specific embodiment. The application uses two glass substrates, a first substrate 100 and a second substrate 200, arranged opposite each other along a first direction. Each substrate has a via array with a diameter of 0.4–1 mm and an aspect ratio ≤15:1, etched from its back side using laser-induced wet etching. The bottom of the vias retains an intact glass layer to ensure mechanical strength and sealing. Subsequently, copper is directly filled into the vias through barrier-free electroplating, connecting adjacent vias at opposite angles to form a three-dimensional spiral coil around the first direction at a macroscopic level. This creates a low-resistance, high-turns-ratio inductive element integrated with the glass within the two substrates. The opposing surfaces of the first substrate 100 and the second substrate 200 are respectively recessed into a first groove 120 and a second groove 220, which, when bonded together, form a serpentine microchannel. For example, the height of the microchannel is 30–50 μm, and its width matches the via array arrangement. The bonding interface uses a low-temperature adhesive layer to complete the liquid seal packaging, leaving only the sample inlet and outlet. This ensures that the sample is always covered by the near-field gradient magnetic field generated by the copper coil during the flow process. The magnetic beads do not need to enter the orifice to disturb the magnetic flux within the orifice area, achieving high-sensitivity detection.

[0043] The inductor amplifies, filters, and converts the differential signal caused by the number of magnetic beads into a digital value through an external differential readout circuit. This digital signal is then uploaded to the cloud via Bluetooth or Wi-Fi by a wireless module, enabling real-time quantitative analysis within 1–3 minutes. The glass substrate exhibits near-zero corrosion within a pH range of 1–13, has a thermal expansion coefficient close to that of copper, and exhibits extremely low resistance drift after long-term thermal cycling. Laser etching and barrier-free electroplating processes eliminate the need for multiple barrier layers, seed layers, and CMP (chemical mechanical polishing) steps required for silicon TSVs (Through Silicon Vias), significantly reducing per-wafer costs. Furthermore, thousands of units can be fabricated in parallel on the same wafer size, making it suitable for large-scale, one-time applications. The overall structure compresses the 3D coil, microfluidics, and wireless interface between two glass substrates, resulting in a smaller chip area, enhanced magnetic field gradient, reliable sealing, and a wide process window. This provides an ideal platform that balances performance, cost, and mass production for POCT (point-of-care testing), distributed monitoring, and point-of-care biological detection in extreme environments.

[0044] The above are merely preferred embodiments of the present invention and do not limit the scope of the patent. Any equivalent structural transformations made using the contents of the specification and drawings of the present invention under the inventive concept of the present invention, or direct / indirect applications in other related technical fields, are included within the scope of patent protection of the present invention.

Claims

1. An inductive biosensor integrated on a TGV, characterized in that, The device includes a first substrate, a second substrate, and a conductive material. The first substrate and the second substrate are disposed opposite to each other along a first direction. The first substrate has a first through hole that penetrates the first substrate along the first direction. The second substrate has a second through hole that penetrates the second substrate along the first direction. Both the first through hole and the second through hole are filled with the conductive material. The conductive materials within the first and second through holes together form a spiral conductive path surrounding the first direction to constitute an inductor element. The inductive biosensor integrated on the TGV also has a microchannel. The surface of the first substrate facing the second substrate and the surface of the second substrate facing the first substrate are both configured as the inner wall of the microchannel. Along a direction perpendicular to the first direction, the microchannel is spaced apart from the first through hole and the second through hole, respectively. The microchannel is adapted to accommodate the test medium and the magnetic bead. The inductive element can generate a magnetic field to sense the magnetic bead and generate an inductance change.

2. The inductive biosensor integrated on the TGV according to claim 1, characterized in that, The first through hole and the second through hole are alternately distributed in a plane perpendicular to the first direction, and the inclination directions of the line connecting the ends of the conductive material in adjacent first through holes and the line connecting the ends of the conductive material in adjacent second through holes are opposite to form the spiral conductive path.

3. The inductive biosensor integrated on the TGV according to claim 1, characterized in that, The diameter of the first through hole and / or the second through hole is in the range of 0.02~0.09mm; and / or the depth-to-width ratio of the first through hole and / or the second through hole is less than or equal to 15:

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4. The inductive biosensor integrated on the TGV according to claim 1, characterized in that, The conductive material includes copper, a copper layer is deposited on the surface of the first substrate, and a copper layer is deposited on the surface of the second substrate; and / or... The first substrate includes a glass substrate, and the second substrate includes a glass substrate.

5. The inductive biosensor integrated on the TGV according to claim 1, characterized in that, The surface of the first substrate is recessed toward the surface of the second substrate to form a first groove, and the surface of the second substrate is recessed toward the surface of the first substrate to form a second groove. The first substrate is attached to the second substrate so that the first groove and the second groove together define the microchannel.

6. The inductive biosensor integrated on the TGV according to claim 5, characterized in that, An adhesive layer is provided between the first substrate and the second substrate to seal the microchannel and bond the first substrate and the second substrate.

7. The inductive biosensor integrated on a TGV according to any one of claims 1-6, characterized in that, The inductive biosensor integrated on the TGV also includes: A differential readout circuit is coupled to the inductor element, and the differential readout circuit is used to convert the inductance change into a voltage signal; A wireless module is coupled to the differential readout circuit, and the wireless module is used to send the detection results to an external terminal.

8. A manufacturing method, characterized in that, The method for fabricating an inductive biosensor integrated on a TGV according to any one of claims 1-6 includes: A first substrate and a second substrate are provided; A first through-hole is formed in the first substrate, and a second through-hole is formed in the second substrate; The first through hole and the second through hole are filled with conductive material to form the spiral conductive path; A microchannel is formed between the first substrate and the second substrate, and the spiral conductive path surrounds at least a portion of the microchannel.

9. The manufacturing method according to claim 8, characterized in that, The step of forming a first through-hole in the first substrate and a second through-hole in the second substrate includes: The first through-hole and / or the second through-hole are formed by laser-induced wet etching; The conductive material is directly filled into the through hole using a barrier-free electroplating process.

10. The manufacturing method according to claim 8, characterized in that, After the step of forming a microchannel between the first substrate and the second substrate, and the helical conductive path surrounding at least a portion of the microchannel, the fabrication method further includes: The inductor is electrically connected to the differential readout circuit; The sensor is encapsulated so that the microchannel retains only the inlet and outlet.

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