Small-point-diameter electrofluid jet chip and forming method

Abstract

The invention relates to a small-point-diameter electrofluid jet chip and a forming method, and the small-point-diameter electrofluid jet chip comprises a jet plate which comprises an SOI silicon plate; a plurality of annular grooves are formed in the surface of the top silicon layer to form a plurality of bosses, the depth of the annular grooves is smaller than the thickness of the top silicon layer, coaxial jet holes are formed in the surfaces of the bosses, and the jet holes penetrate through the top silicon layer and the buried oxide layer; a plurality of liquid inlet holes are formed in the surface of the bottom silicon layer, and the depth of the liquid inlet holes is consistent with the thickness of the bottom silicon layer, so that the spraying holes are communicated with the liquid inlet holes; and the electrode structure comprises a plurality of electrode rings, the plurality of electrode rings are connected to the bottom surface of the spraying plate, the plurality of electrode rings surround the plurality of annular grooves respectively, and potential differences exist between the electrode rings and the bosses corresponding to the electrode rings. The injection hole is etched in the top silicon layer of the SOI silicon plate, so that the depth of the injection hole is shortened, the machining precision of the injection hole is guaranteed, the machining precision of the small-aperture injection hole is guaranteed, and the requirement for high-precision printing is met.

Description

Technical Field

[0001] This application relates to the field of electrofluid printing technology, and in particular to a small-diameter electrofluid jet chip and its forming method. Background Technology

[0002] Inkjet printing, as a direct-write additive manufacturing technology, boasts advantages such as no need for masks, flexible production, and high material utilization, showing promising application prospects in fields such as printed displays, printed circuits, and printed solar cells. Electrohydraulic inkjet printing, in particular, uses an electric field as the primary driving force, significantly enhancing the ink's driving power and enabling the printing of high-viscosity inks. Furthermore, because the ink is ejected locally from the meniscus, the resulting droplet size can be much smaller than the nozzle diameter, thus significantly improving printing resolution. Electrohydraulic inkjet printing technology overcomes two major drawbacks of traditional inkjet printing technologies and has broad application prospects.

[0003] In related technologies, a groove is machined on the bottom surface of a substrate, and a boss is formed within the groove by machining an annular groove. A through-hole is then formed on the boss. Electrodes are arranged on the bottom surface of the substrate. Due to the arrangement of the groove, there is a height difference between the nozzle of the spray hole and the electrode, which creates a potential difference between the nozzle and the electrode. The functional liquid in the spray hole can then be ejected using an electric field.

[0004] The size of the ejected ink droplets is related to the diameter of the ejection orifice. By reducing the diameter of the ejection orifice, smaller ink droplets can be printed, thereby improving printing accuracy.

[0005] The diameter of the injection hole is related to its depth. When the diameter of the injection hole is small, the depth of the injection hole is large due to limitations in the processing technology, which makes it impossible to guarantee the consistency of the injection hole diameter and thus affects the forming accuracy and consistency of the injection hole.

[0006] However, since the jetting holes need to penetrate the substrate, it is difficult to control their length, thus compromising the processing quality of the hole diameter. Even if a recessed groove is created at the top of the substrate to thin it and shorten the processing depth of the jetting holes, the depth of the recessed groove is difficult to control precisely due to process limitations, resulting in poor depth consistency among multiple jetting holes and affecting printing consistency. Therefore, the difficulty in reducing the depth of the jetting holes makes it difficult to reduce their diameter, making it difficult to print smaller ink droplets on the jetting chip, resulting in poor printing accuracy. Summary of the Invention

[0007] This application provides a small-diameter current fluid jet chip and a forming method to solve the technical problem in related technologies that the depth of the jet hole is difficult to reduce, which makes it difficult to reduce the diameter of the jet hole, making it difficult to print small ink droplets and resulting in poor printing accuracy.

[0008] Firstly, a small-diameter current jet chip is provided, comprising: The spraying plate includes an SOI silicon substrate, which sequentially comprises a top silicon layer, a buried oxide layer, and a bottom silicon layer. The bottom surface of the top silicon layer is the bottom surface of the spraying plate, and the top surface of the bottom silicon substrate is the top surface of the spraying plate. Multiple annular grooves are formed on the surface of the top silicon layer to create multiple bosses. The depth of the annular grooves is less than the thickness of the top silicon layer. Coaxial spraying holes are formed on the surfaces of the multiple bosses, and the spraying holes pass through the top silicon layer and the buried oxide layer. Multiple liquid inlet holes are formed on the surface of the bottom silicon layer, and the depth of the liquid inlet holes is the same as the thickness of the bottom silicon layer, so that the spraying holes communicate with the liquid inlet holes. The electrode structure includes multiple electrode rings, each of which is connected to the bottom surface of the spray plate and surrounds multiple annular grooves. There is a potential difference between the electrode rings and the corresponding bosses.

[0009] In some embodiments, the small-diameter current jet chip further includes a thickened layer formed on the bottom surface of the jetting plate. The thickened layer has a plurality of connecting grooves on its surface, which are respectively connected to a plurality of annular grooves and cover the annular grooves. The electrode structure is formed on the bottom surface of the thickened layer.

[0010] In some embodiments, the small-diameter current jet chip further includes a mask layer formed on the thickened layer and the bottom surface of the boss, the mask layer leaving positions for the multiple annular grooves on the surface of the top silicon layer, and the electrode structure formed on the bottom surface of the mask layer.

[0011] In some embodiments, the plurality of liquid inlet holes are arranged coaxially with the plurality of annular grooves, and the diameter of the liquid inlet holes is not less than ten times the outer diameter of the annular grooves.

[0012] In some embodiments, the electrode structure further includes a plurality of leads, each of which is connected to the surface of the mask layer, and each of the leads is electrically connected to a plurality of electrode rings, and each of the leads is electrically connected to an external flexible circuit board.

[0013] In some embodiments, the surface of the spray plate is provided with multiple connecting holes, and the thickened layer and the mask layer have notches at the positions corresponding to the connecting holes; a conductive ring is arranged in the connecting hole, the bottom of the conductive ring extends to the bottom surface of the mask layer and is electrically connected to the lead wire, and the top of the conductive ring is electrically connected to the external flexible circuit board.

[0014] In some embodiments, the small-diameter current jet chip further includes a passivation layer covering the electrode ring and the lead surface.

[0015] In some embodiments, the small-diameter current jet chip further includes a hydrophobic layer covering the passivation layer and the bottom surface of the mask layer.

[0016] The beneficial effects of the technical solution provided in this application include: This application provides a small-diameter fluid jetting chip using an SOI silicon substrate as the jetting plate. The jetting plate comprises a three-layer structure: a top silicon layer, a buried oxide layer, and a bottom silicon layer. During etching of the jetting plate, high-precision etching can be performed on the corresponding layer surfaces, ensuring the flatness of the processed surface. The thickness of the top silicon layer is less than that of the bottom silicon layer, typically around 10 micrometers, while the thickness of the buried oxide layer is at the nanometer level. By creating jetting holes on the surface of the top silicon layer and extending these holes to the bottom silicon layer, the processing depth of the jetting holes can be controlled, shortening the processing depth and ensuring the processing quality of the small-diameter jetting holes. This ensures the consistency of the hole diameter within the small-diameter jetting holes, thereby improving printing quality and ensuring high-quality printing of small-sized droplets.

[0017] Furthermore, by creating inlet holes on the top surface of the spray plate, extending to the surface of the embedded oxide layer, the spray holes are connected. Due to the barrier effect of the embedded oxide layer, the depth of the inlet holes is controlled, resulting in better flatness and smoothness at the bottom of the inlet holes. Therefore, it is less likely that the spray holes will not be connected, or that the inlet holes will be machined too deep, shortening the spray holes, thus ensuring the consistency of the machining depth of multiple spray holes. Moreover, by creating inlet holes, the functional liquid is collected in a larger inlet hole before entering the spray holes, ensuring a stable ink supply to the spray holes. The flatness of the inlet hole bottom improves the flow stability of the functional liquid, guaranteeing the stability of the ink supply to the spray holes.

[0018] Furthermore, the annular groove is formed on the surface of the top silicon layer, creating a boss that allows the functional fluid to form a stable Taylor cone on the bottom surface of the boss, thus ensuring printing accuracy. The annular groove also separates the bosses, preventing functional fluid from overflowing from the injection holes and causing chip contamination or damage. Because the depth of the annular groove is less than the thickness of the top silicon layer, a portion of the top silicon layer is retained as a support layer, improving the overall chip structure to support the size design of the fluid inlet holes, ensuring the overall structural stability of the chip, and thus guaranteeing printing quality.

[0019] Finally, multiple electrode rings are used to correspond to different jet holes. By controlling the voltage of different electrode rings, the individual control of multiple jet holes can be achieved, thus realizing multi-hole controllable printing.

[0020] Secondly, a method for forming a small-diameter current-jet chip is provided, for forming the small-diameter current-jet chip as described above, comprising the following steps: SOI silicon substrates are obtained as spray plates. The SOI silicon substrates consist of a bottom silicon layer, a buried oxide layer, and a top silicon layer from top to bottom. A thickened layer is deposited on the bottom surface of the spray plate; Multiple jetting windows are etched into the bottom surface of the thickened layer to expose the top silicon layer; Multiple jet holes are etched on the bottom surface of the top silicon layer, and the jet holes extend to the bottom surface of the bottom silicon layer. A mask layer is formed on the bottom surface of the spray plate, and multiple annular grooves are etched on the bottom surface of the spray plate through the mask to form multiple bosses. The spray holes are coaxial with the bosses. The depth of the annular grooves is less than the thickness of the top silicon layer. An electrode structure is patterned on the bottom surface of the mask layer; A passivation layer is deposited on the surface of the electrode structure; A hydrophobic layer is formed on the bottom surface of the passivation layer and the bottom surface of the mask layer.

[0021] In some embodiments, the method for forming the small-diameter current jet chip further includes: Multiple connecting holes are made at the edge of the spray plate, and corresponding notches are made in the mask layer and the thickened layer that communicate with the connecting holes; A conductive ring is deposited and formed within the connecting hole, and the conductive ring extends to connect with the electrode structure.

[0022] This application provides a method for forming a small-diameter current-electrode chip. Since this method is used to form the small-diameter current-electrode chip, the beneficial effects of this method are the same as those of the small-diameter current-electrode chip, and will not be repeated here. Attached Figure Description

[0023] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0024] Figure 1 A schematic diagram of a small-diameter current jet chip provided in an embodiment of this application; Figure 2 This is a schematic diagram of a small-diameter current jet chip provided in another embodiment of this application.

[0025] In the figure: 1. Spray plate; 11. Top silicon layer; 12. Buried oxide layer; 13. Bottom silicon layer; 14. Boss; 1a. Spray hole; 1b. Annular groove; 1c. Liquid inlet hole; 1d. Connecting hole; 2. Thickened layer; 3. Mask layer; 4. Electrode structure; 41. Electrode ring; 42. Lead wire; 5. Passivation layer; 6. Hydrophobic layer; 7. Conductive ring. Detailed Implementation

[0026] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0027] This application provides a small-diameter current fluid jetting chip and its forming method. By etching jetting holes at the top silicon layer of an SOI silicon substrate, the depth of the jetting holes is shortened, thus ensuring the processing accuracy of the small-diameter holes and meeting the requirements of high-precision printing. This application solves the technical problem in related technologies where the depth of the jetting holes is difficult to reduce, leading to difficulty in reducing the diameter of the jetting holes, making it difficult to print small ink droplets and resulting in poor printing accuracy.

[0028] Reference Figure 1 A small-diameter electrofluid injection chip includes an injection plate 1 and an electrode structure 4. The bottom surface of the injection plate 1 has multiple annular grooves 1b forming multiple protrusions 14, each with a coaxial injection hole 1a on its bottom surface. The top surface of the injection plate 1 has corresponding multiple liquid inlet holes 1c, each coaxially corresponding to one of the injection holes 1a. The electrode structure 4 is arranged on the bottom surface of the injection plate 1. A voltage is applied to the electrode structure 4 to drive the functional liquid out of the injection holes 1a using an electric field.

[0029] With this configuration, the spray plate 1 is thinned through the liquid inlet hole 1c to make the spray hole 1a accessible. The spray hole 1a can be made shallower if the required depth is not needed, thus providing a basis for processing small-diameter spray holes 1a. This enables the processing of small-diameter spray holes 1a and ensures the consistency of the diameter of each part of the spray hole 1a.

[0030] Reference Figure 1 Specifically, the spray plate 1 includes an SOI silicon substrate, which sequentially comprises a top silicon layer 11, a buried oxide layer 12, and a bottom silicon layer 13. The bottom surface of the top silicon layer 11 is the bottom surface of the spray plate 1, and the top surface of the bottom silicon layer is the top surface of the spray plate 1. The spray plate 1 comprises, from top to bottom, a bottom silicon layer 13, a buried oxide layer 12, and a top silicon layer 11. Both the bottom silicon layer 13 and the top silicon layer 11 are silicon layers, and the buried oxide layer 12 is a silicon dioxide layer.

[0031] Reference Figure 1 Both the annular groove 1b and the injection hole 1a are formed on the bottom surface of the top silicon layer 11. The injection hole 1a passes through the top silicon layer 11 and the buried oxide layer 12 to the bottom silicon layer 13.

[0032] With this configuration, the bottom silicon layer 13 is relatively thick, the top silicon layer 11 is relatively thin, typically around 10 micrometers, and the buried oxide layer 12 is typically at the nanometer level, ranging from 10 to 50 nanometers. Therefore, the jetting hole 1a penetrates the top silicon layer 11, and its depth is controlled to approximately 10 micrometers. By creating the jetting hole 1a on the surface of the top silicon layer 11 and extending it to the bottom silicon layer 13, the processing depth of the jetting hole 1a is controlled, shortening its processing depth. This ensures the processing quality of the small-diameter jetting hole 1a, guarantees the consistency of the aperture processing within the small-diameter jetting hole 1a, improves printing quality, and ensures high-quality printing of small droplets.

[0033] Reference Figure 1 Furthermore, the liquid inlet hole 1c is formed on the top surface of the bottom silicon layer 13, and the depth of the liquid inlet hole 1c is consistent with the thickness of the bottom silicon layer 13, so that the spray hole 1a is connected to the liquid inlet hole 1c.

[0034] With this configuration, the liquid inlet hole 1c extends to the surface of the buried oxide layer 12, thereby connecting the jet hole 1a. Due to the blocking effect of the buried oxide layer 12, the depth of the liquid inlet hole 1c is controlled, resulting in good flatness and smoothness at the bottom of the liquid inlet hole 1c. Therefore, it is less likely that the jet hole 1a will not be connected, or that the liquid inlet hole 1c will be machined too deep, shortening the jet hole 1a, thus ensuring the consistency of the machining depth of multiple jet holes 1a. Furthermore, by opening the liquid inlet hole 1c, the functional liquid is collected in the larger liquid inlet hole 1c before entering the jet hole 1a, ensuring a stable ink supply to the jet hole 1a. The flatness of the bottom of the liquid inlet hole 1c improves the flow stability of the functional liquid, ensuring the stability of the ink supply to the jet hole 1a.

[0035] Reference Figure 1 Specifically, multiple liquid inlet holes 1c are arranged coaxially with multiple annular grooves 1b, and the diameter of the liquid inlet hole 1c is not less than ten times the outer diameter of the annular groove 1b.

[0036] This configuration allows the functional liquid to accumulate through the inlet hole 1c, ensuring a stable ink supply to the small-diameter jet holes 1a and guaranteeing print quality. The portion of the top silicon layer 11 reserved due to the depth arrangement of the annular groove 1b supports the aperture design of the inlet hole 1c, ensuring stable ink supply to multiple jet holes 1a while maintaining the structural strength of the chip itself.

[0037] Reference Figure 1 The annular groove 1b is formed on the bottom surface of the top silicon layer 11, and the boss 14 is formed by forming the annular groove 1b. The depth of the annular groove 1b is less than the thickness of the top silicon layer 11.

[0038] With this configuration, the annular groove 1b is formed on the surface of the top silicon layer 11, creating a protrusion 14. This allows the functional fluid to form a stable Taylor cone on the bottom surface of the protrusion 14, ensuring printing accuracy. Furthermore, the annular groove 1b separates the protrusion 14, preventing functional fluid from overflowing from the injection hole 1a and causing chip contamination or damage. Since the depth of the annular groove 1b is less than the thickness of the top silicon layer 11, a portion of the top silicon layer 11 is retained as a support layer, enhancing the overall chip structure to support the size design of the fluid inlet hole 1c. This ensures the overall structural stability of the chip, thereby guaranteeing printing quality.

[0039] It is important to note that during the fabrication of the annular groove 1b, a specified thickness is formed on the top silicon layer 11. Due to the relatively small depth of the annular groove 1b, the morphology of the groove bottom can still be guaranteed after etching to the specified thickness. Furthermore, even if the morphology of the groove bottom of the annular groove 1b is not ideal, it will not affect the printing quality.

[0040] Reference Figure 1 The electrode structure 4 includes multiple electrode rings 41, which are all connected to the bottom surface of the spray plate 1 and surround multiple annular grooves 1b respectively. There is a potential difference between the electrode rings 41 and the corresponding bosses 14.

[0041] With this configuration, multiple electrode rings 41 are used to correspond to different jet holes 1a. By controlling the voltage of different electrode rings 41, the individual control of multiple jet holes 1a can be achieved, thus realizing multi-hole controllable printing.

[0042] Reference Figure 1 The small-diameter current fluid jet chip also includes a thickened layer 2, which is formed on the bottom surface of the jetting plate 1. The surface of the thickened layer 2 has multiple connecting grooves, which are connected to multiple annular grooves 1b and cover the annular grooves 1b. The electrode structure 4 is formed on the bottom surface of the thickened layer 2.

[0043] Specifically, the connecting groove covers the annular groove 1b, preferably with the outer diameter of the connecting groove matching the outer diameter of the annular groove 1b. In this embodiment, a connecting groove is first made on the bottom surface of the spray plate 1 to expose part of the spray plate 1, and then a spray hole 1a and an annular groove 1b are made at the bottom of the connecting groove.

[0044] This configuration, by arranging the thickened layer 2, increases the distance between the electrode structure 4 and the outlet of the injection hole 1a, thereby establishing a height difference between the outlet of the injection hole and the electrode ring 41, thus forming a stable potential difference between the boss 14 and the electrode ring 41, ensuring stable injection of the functional liquid.

[0045] The thickened layer 2 comprises one or more of silicon dioxide and silicon nitride. By arranging the thickened layer 2, which serves as an insulating layer, the electrode structure 4 and the spray plate 1 are separated by the thickened layer 2, thereby improving the high voltage resistance of the spray plate 1 and preventing the spray plate 1 from being broken down due to excessive voltage.

[0046] Reference Figure 1 The small-diameter current jet chip also includes a mask layer 3, which is formed on the bottom surface of the thickened layer 2 and the boss 14. The mask layer 3 leaves multiple annular grooves 1b on the surface of the top silicon layer 11, and the electrode structure 4 is formed on the bottom surface of the mask layer 3.

[0047] Specifically, after forming the thickened layer 2 and opening the connecting groove, the annular groove 1b needs to be processed using a mask method. By forming a mask layer 3 on the surface of the thickened layer 2 at the position of the preset boss 14, the position of the annular groove 1b is left, so that the annular groove 1b can be etched and formed at this time.

[0048] In this embodiment, the mask layer 3 includes silicon dioxide or silicon nitride. By using the mask layer 3 to block the flow, the annular groove 1b is precisely etched at a position on the bottom surface of the top silicon layer 11 of the spray plate 1.

[0049] This configuration, through the arrangement of the mask layer 3, not only improves the machining accuracy of the annular groove 1b, but also ensures the machining accuracy at the bottom edge of the boss 14 after its formation. The edge of the bottom surface of the boss 14 is less prone to roughness or gaps, thus ensuring the stable formation of a Taylor cone of functional liquid on the bottom surface of the boss 14. Furthermore, since the electrode structure 4 is arranged on the bottom surface of the mask layer 3, the height difference between the electrode structure 4 and the outlet of the injection hole 1a is further increased, ensuring a stable potential difference between the boss 14 and the electrode ring 41, guaranteeing stable ejection of the functional liquid. Additionally, since the mask layer 3 is also made of insulating material, it further improves the high-voltage resistance of the injection plate 1, preventing the injection plate 1 from being damaged by excessive voltage.

[0050] Reference Figure 1 The electrode structure 4 also includes multiple leads 42, which are all connected to the surface of the mask layer 3. The multiple leads 42 are electrically connected to multiple electrode rings 41, and the multiple leads 42 are all electrically connected to an external flexible circuit board.

[0051] In some embodiments, when the annular groove 1b is processed by other methods without the need for the mask layer 3, the lead wire 42 is disposed on the bottom surface of the thickened layer 2.

[0052] In this embodiment, both the electrode ring 41 and the lead wire 42 are fabricated by deposition.

[0053] The electrode ring 41 and the lead wire 42 are made of one or more of the following materials: gold, silver, copper, aluminum, and chromium.

[0054] Reference Figure 1 With this configuration, multiple electrode rings 41 are used to correspond to different jet holes 1a. By controlling the voltage of different electrode rings 41, the individual control of multiple jet holes 1a can be achieved, thus realizing multi-hole controllable printing.

[0055] Reference Figure 2 Optionally, the surface of the spray plate 1 is also provided with multiple connecting holes 1d, and the thickened layer 2 and the mask layer 3 have notches at the positions corresponding to the connecting holes 1d; a conductive ring 7 is arranged in the connecting hole 1d, the bottom of the conductive ring 7 extends to the bottom surface of the mask layer 3 and is electrically connected to the lead wire 42. The top of the conductive ring 7 is electrically connected to the external flexible circuit board.

[0056] Specifically, the conductive ring 7 is made of the same material as the lead wire 42 and the electrode ring 41. Furthermore, the conductive ring 7 is manufactured using a deposition process, specifically deposited within the connecting hole 1d. The conductive ring 7 is electrically connected to the lead wire 42.

[0057] Reference Figure 2 Preferably, the multiple connecting holes 1d are arranged close to the edge of the spray plate 1 to facilitate the connection between the flexible circuit board and the conductive ring 7 at the edge of the spray plate 1.

[0058] This configuration allows for connection to an external flexible circuit board above the spray plate 1, making the form of external voltage more flexible.

[0059] Reference Figure 1 The small-diameter current jet chip also includes a passivation layer 5, which covers the surface of the electrode ring 41 and the lead wire 42.

[0060] Specifically, in this embodiment, the passivation layer 5 is made of silicon dioxide. It is patterned on the surfaces of the electrode ring 41 and the lead 42 using a spray adhesive and metal stripping process to protect the electrode ring 41 and the lead 42. In this embodiment, the end of the lead 42 furthest from the electrode ring 41 is not covered by the passivation layer 5 to leave space for connection to the flexible circuit board.

[0061] Reference Figure 1 The small-diameter current jet chip also includes a hydrophobic layer 6, which covers the bottom surface of the passivation layer 5 and the mask layer 3.

[0062] Specifically, the small-diameter current jet chip also includes a hydrophobic layer 6, which covers the bottom surface of the passivation layer 5 and the mask layer 3.

[0063] Specifically, the hydrophobic layer 6 is made of phenelzine and is applied to the bottom of the sputtering plate 1 via a sputtering process to cover the structure of the bottom surface of the sputtering plate 1. This covers the surface of the passivation layer 5 and the bottom surface of the mask layer 3, meaning the surface of the mask layer 3 on the bottom surface of the boss 14 is also covered by the hydrophobic layer 6. In this embodiment, the end of the lead 42 away from the electrode ring 41 is blocked by a mask, allowing the hydrophobic layer 6 to be formed during sputtering. The end of the lead 42 is not covered by the hydrophobic layer 6 to leave space for connection with the flexible circuit board.

[0064] This arrangement of the hydrophobic layer 6 allows the functional liquid to form a more stable meniscus on the bottom surface of the boss 14, preventing the functional liquid from overflowing.

[0065] This application provides a small-diameter fluid jetting chip, using an SOI silicon substrate as the jetting plate 1. The jetting plate 1 comprises a three-layer structure: a top silicon layer 11, a buried oxide layer 12, and a bottom silicon layer 13. During etching of the jetting plate 1, high-precision etching can be performed on the corresponding layer surfaces, ensuring the flatness of the processed surface. The thickness of the top silicon layer 11 is less than that of the bottom silicon layer 13, and the thickness of the top silicon layer 11 is generally around 10 micrometers, while the thickness of the buried oxide layer 12 is at the nanometer level. By opening jetting holes 1a on the surface of the top silicon layer 11 and extending the jetting holes 1a to the bottom silicon layer 13, the processing depth of the jetting holes 1a can be controlled, shortening the processing depth of the jetting holes 1a. This ensures the processing quality of the small-diameter jetting holes 1a, guarantees the consistency of the hole diameter processing within the small-diameter jetting holes 1a, thereby improving printing quality and ensuring high-quality printing of small-sized droplets.

[0066] Furthermore, by opening a liquid inlet hole 1c on the top surface of the spray plate 1, extending to the surface of the embedded oxide layer 12, the spray hole 1a is connected. Due to the blocking effect of the embedded oxide layer 12, the opening depth of the liquid inlet hole 1c is controlled, resulting in better flatness and smoothness of the bottom of the liquid inlet hole 1c. Therefore, it is less likely that the spray hole 1a will not be connected, or that the liquid inlet hole 1c will be machined too deep, shortening the spray hole 1a, thus ensuring the consistency of the machining depth of multiple spray holes 1a. Moreover, by opening the liquid inlet hole 1c, the functional liquid is collected in the larger liquid inlet hole 1c before entering the spray hole 1a, ensuring a stable ink supply to the spray hole 1a. The flatness of the bottom of the liquid inlet hole 1c improves the flow stability of the functional liquid, ensuring the stability of the ink supply to the spray hole 1a.

[0067] Furthermore, the annular groove 1b is formed on the surface of the top silicon layer 11, creating a protrusion 14. This allows the functional liquid to form a stable Taylor cone on the bottom surface of the protrusion 14, thus ensuring printing accuracy. The annular groove 1b also separates the protrusion 14, preventing functional liquid from overflowing from the injection hole 1a and causing chip contamination or damage. Because the depth of the annular groove 1b is less than the thickness of the top silicon layer 11, a portion of the top silicon layer 11 is retained as a support layer, improving the overall structure of the chip to support the size design of the liquid inlet hole 1c, ensuring the overall structural stability of the chip, and thus guaranteeing printing quality.

[0068] Finally, multiple electrode rings 41 are used to correspond to different jet holes 1a. By controlling the voltage of different electrode rings 41, the multiple jet holes 1a can be individually controlled, thus realizing multi-hole controllable printing.

[0069] Another embodiment of this application provides a method for forming a small-diameter electrofluid jet chip, used to form the small-diameter electrofluid jet chip as described above, including steps S100-S900: S100. Obtain an SOI silicon substrate as a spray plate 1. The SOI silicon substrate includes a bottom silicon layer 13, a buried oxide layer 12 and a top silicon layer 11 from top to bottom.

[0070] S200, deposit a thickened layer 2 on the bottom surface of the spray plate 1.

[0071] S300, Multiple jet windows are etched on the bottom surface of the thickened layer 2 to expose the top silicon layer 11.

[0072] S400, a plurality of jet holes 1a are etched on the bottom surface of the top silicon layer 11, and the jet holes 1a extend to the bottom surface of the bottom silicon layer 13.

[0073] S500, a mask layer 3 is formed on the bottom surface of the thickened layer 2 and the bottom surface of the spray plate 1. Multiple annular grooves 1b are formed on the bottom surface of the spray plate 1 by etching through the mask to form multiple bosses 14. The spray hole 1a is coaxial with the bosses 14. The depth of the annular groove 1b is less than the thickness of the top silicon layer 11.

[0074] S600. Multiple liquid inlet holes 1c are etched on the top surface of the spray plate 1. The multiple liquid inlet holes 1c correspond one-to-one with the multiple spray holes 1a. The liquid inlet holes 1c are opened to the top surface of the buried oxygen layer 12 to communicate with the spray holes 1a.

[0075] S700, an electrode structure 4 is patterned on the bottom surface of the mask layer 3.

[0076] S800, deposit a passivation layer 5 on the surface of electrode structure 4.

[0077] S900, a hydrophobic layer 6 is formed on the bottom surface of the passivation layer 5 and the bottom surface of the mask layer 3.

[0078] In step S100, an SOI silicon board is obtained as a spray plate 1. The SOI silicon board includes a bottom silicon layer 13, a buried oxide layer 12 and a top silicon layer 11 from top to bottom.

[0079] Specifically, the bottom silicon layer 13 and the top silicon layer 11 are both silicon layers, and the buried oxide layer 12 is a silicon dioxide layer. The thickness of the bottom silicon layer 13 is greater than the thickness of the top silicon layer 11, and the thickness of the top silicon layer 11 is 10-20 micrometers. The thickness of the buried oxide layer 12 is 5-100 nanometers. Because the bottom silicon layer 13, the top silicon layer 11, and the buried oxide layer 12 are made of different materials, during etching, when etching from the surface of the top silicon layer 11 to the surface of the buried oxide layer 12, or from the surface of the bottom silicon layer 13 to the surface of the buried oxide layer 12, the flatness of the etched surface is better due to the barrier effect of the buried oxide layer 12.

[0080] In this embodiment, the bottom silicon layer 13, the buried oxide layer 12, and the top silicon layer 11 are arranged sequentially from top to bottom. The top surface of the bottom silicon layer 13 is the top surface of the spray plate 1, and the bottom surface of the top silicon layer 11 is the bottom surface of the spray plate 1.

[0081] In step S200, a thickened layer 2 is deposited on the bottom surface of the spray plate 1.

[0082] Specifically, a thickened layer 2 is deposited on the bottom surface of the spray plate 1. The material of the thickened layer 2 includes at least one of silicon dioxide and silicon nitride. In this embodiment, the thickened layer 2 is a composite film of silicon dioxide and silicon nitride. The thickness of the thickened layer 2 is preferably 5-8 micrometers.

[0083] This design thickens the spray plate 1 and improves its high-pressure resistance.

[0084] In step S300, multiple jet windows are etched on the bottom surface of the thickened layer 2 to expose the top silicon layer 11.

[0085] Specifically, multiple spray windows are etched on the bottom surface of the thickened layer 2, and the depth of the spray windows is consistent with the thickness of the thickened layer 2, thereby exposing the bottom surface of the spray plate 1, that is, the bottom surface of the top silicon layer 11. The spray windows are used to create the processing positions for the spray holes 1a and the annular groove 1b.

[0086] In step S400, a plurality of jet holes 1a are etched on the bottom surface of the top silicon layer 11, and the jet holes 1a extend to the bottom surface of the bottom silicon layer 13.

[0087] Specifically, within the spray window, a spray hole 1a is etched, and the depth of the spray hole 1a is the sum of the thicknesses of the top silicon layer 11 and the buried oxide layer 12. The bottom surface of the bottom silicon layer 13 is opened in the spray hole 1a.

[0088] This configuration, with its relatively small combined thickness of the top silicon layer 11 and the buried oxide layer 12, controls the machining depth of the injection holes 1a, shortening the machining depth of the injection holes 1a and thus ensuring the machining quality of small-diameter injection holes 1a, guaranteeing the machining quality of injection holes 1a with a diameter of 1-3 micrometers. It also ensures the consistency of the hole diameter machining within the small-diameter injection holes 1a, thereby improving printing quality and ensuring high-quality printing of small-sized droplets. Furthermore, since all injection holes 1a are opened to the bottom surface of the bottom silicon layer 13, the machining consistency of multiple injection holes 1a is ensured.

[0089] In step S500, a mask layer 3 is formed on the bottom surface of the thickened layer 2 and the bottom surface of the spray plate 1. Multiple annular grooves 1b are formed on the bottom surface of the spray plate 1 by etching through the mask to form multiple bosses 14. The spray hole 1a is coaxial with the bosses 14. The depth of the annular groove 1b is less than the thickness of the top silicon layer 11.

[0090] Specifically, a mask layer 3 is first deposited on the bottom surface of the thickened layer 2, and then the mask layer 3 is also deposited on the bottom surface of the spray plate 1 exposed by the spray window. A processing position for the annular groove 1b is left on the bottom surface of the spray plate 1. Then, the annular groove 1b is processed by etching on the bottom surface of the spray plate 1, thereby processing the position where the mask layer 3 is not deposited on the bottom surface of the spray plate 1. The depth of the annular groove 1b is less than the depth of the top silicon layer 11. In this embodiment, the top silicon layer 11 retains a thickness of 5-10 micrometers at the location where the annular groove 1b is formed.

[0091] With this configuration, the annular groove 1b is formed on the surface of the top silicon layer 11, creating a protrusion 14. This allows the functional fluid to form a stable Taylor cone on the bottom surface of the protrusion 14, ensuring printing accuracy. Furthermore, the annular groove 1b separates the protrusion 14, preventing functional fluid from overflowing from the injection hole 1a and causing chip contamination or damage. Since the depth of the annular groove 1b is less than the thickness of the top silicon layer 11, a portion of the top silicon layer 11 is retained as a support layer, enhancing the overall chip structure to support the size design of the fluid inlet hole 1c. This ensures the overall structural stability of the chip, thereby guaranteeing printing quality.

[0092] By arranging the mask layer 3, not only is the machining accuracy of the annular groove 1b improved, but the machining accuracy at the bottom edge of the boss 14 is also ensured after its formation. The edge of the bottom surface of the boss 14 is less prone to roughness or gaps, thus ensuring the stable formation of a Taylor cone of functional liquid on the bottom surface of the boss 14. Furthermore, since the electrode structure 4 is arranged on the bottom surface of the mask layer 3, the height difference between the electrode structure 4 and the outlet of the injection hole 1a is further increased, ensuring a stable potential difference between the boss 14 and the electrode ring 41, guaranteeing stable ejection of the functional liquid. In addition, since the mask layer 3 is also an insulating material, the high-voltage resistance of the injection plate 1 is further improved, preventing the injection plate 1 from being damaged by excessive voltage.

[0093] In this embodiment, the mask layer 3 includes silicon dioxide or silicon nitride.

[0094] In step S600, multiple liquid inlet holes 1c are etched on the top surface of the spray plate 1. The multiple liquid inlet holes 1c correspond one-to-one with the multiple spray holes 1a. The liquid inlet holes 1c are opened to the top surface of the buried oxygen layer 12 to communicate with the spray holes 1a.

[0095] Specifically, the liquid inlet hole 1c is formed on the top surface of the bottom silicon layer 13, and the depth of the liquid inlet hole 1c is the same as the thickness of the bottom silicon layer 13, so that the spray hole 1a is connected to the liquid inlet hole 1c. Multiple liquid inlets 1c are arranged coaxially with multiple annular grooves 1b, and the diameter of the liquid inlet hole 1c is not less than ten times the outer diameter of the annular groove 1b.

[0096] With this configuration, the liquid inlet hole 1c extends to the surface of the buried oxide layer 12, thereby connecting the jet hole 1a. Due to the blocking effect of the buried oxide layer 12, the depth of the liquid inlet hole 1c is controlled, resulting in good flatness and smoothness at the bottom of the liquid inlet hole 1c. Therefore, it is less likely that the jet hole 1a will not be connected, or that the liquid inlet hole 1c will be machined too deep, shortening the jet hole 1a, thus ensuring the consistency of the machining depth of multiple jet holes 1a. Furthermore, by opening the liquid inlet hole 1c, the functional liquid is collected in the larger liquid inlet hole 1c before entering the jet hole 1a, ensuring a stable ink supply to the jet hole 1a. The flatness of the bottom of the liquid inlet hole 1c improves the flow stability of the functional liquid, ensuring the stability of the ink supply to the jet hole 1a.

[0097] The functional liquid is collected through the liquid inlet 1c to ensure a stable ink supply to the small-diameter jet holes 1a, thus guaranteeing print quality. The portion of the top silicon layer 11 reserved due to the depth arrangement of the annular groove 1b supports the aperture design of the liquid inlet 1c, ensuring a stable ink supply to multiple jet holes 1a while maintaining the structural strength of the chip itself.

[0098] In step S700, an electrode structure 4 is patterned on the bottom surface of the mask layer 3.

[0099] Specifically, a deposition process is used to pattern the electrode structure 4. That is, multiple electrode rings 41 are formed around the annular groove 1b at the bottom of the mask layer 3, and leads 42 electrically connected to the electrode rings 41 are formed.

[0100] In some embodiments, the electrode structure 4 can be formed on the surface of the thickened layer 2 without using a mask method to etch the annular groove 1b.

[0101] In step S800, a passivation layer 5 is deposited on the surface of the electrode structure 4.

[0102] Specifically, a passivation layer 5 is deposited on the surfaces of the electrode ring 41 and the lead 42. The passivation layer 5 is preferably silicon dioxide, and its thickness is preferably 300-500 nanometers. The passivation layer 5 is applied to the surfaces of the electrode ring 41 and the lead 42 using a spray adhesive and metal stripping process to protect them. In this embodiment, the end of the lead 42 furthest from the electrode ring 41 is not covered with the passivation layer 5 to leave space for connection to the flexible circuit board.

[0103] In step S900, a hydrophobic layer 6 is formed on the bottom surface of the passivation layer 5 and the bottom surface of the mask layer 3.

[0104] Specifically, the hydrophobic layer 6 is made of phenelzine and is applied to the bottom of the sputtering plate 1 via a sputtering process to cover the structure of the bottom surface of the sputtering plate 1. This covers the surface of the passivation layer 5 and the bottom surface of the mask layer 3, meaning the surface of the mask layer 3 on the bottom surface of the boss 14 is also covered by the hydrophobic layer 6. In this embodiment, the end of the lead 42 away from the electrode ring 41 is blocked by a mask, allowing the hydrophobic layer 6 to be formed during sputtering. The end of the lead 42 is not covered by the hydrophobic layer 6 to leave space for connection with the flexible circuit board.

[0105] This arrangement of the hydrophobic layer 6 allows the functional liquid to form a more stable meniscus on the bottom surface of the boss 14, preventing the functional liquid from overflowing.

[0106] In other embodiments, the method for forming the small-diameter current jet chip further includes: Multiple connecting holes 1d are made at the edge of the spray plate 1, and corresponding notches are made in the mask layer 3 and the thickened layer 2 that communicate with the connecting holes 1d.

[0107] A conductive ring 7 is deposited within the connecting hole 1d, and the conductive ring 7 extends to connect with the electrode structure 4.

[0108] Specifically, when the spray window is opened in the thickened layer 2, the connecting hole 1d is simultaneously etched at the position where the connecting hole 1d needs to be opened, and the opening depth of the connecting hole 1d is consistent with the depth of the spray window.

[0109] When etching the jet hole 1a, the connecting hole 1d is simultaneously further etched to deepen it, and the depth of the further etching of the connecting hole 1d is consistent with the depth of the jet hole opening.

[0110] When the liquid inlet hole 1c is being processed, the connecting hole 1d is simultaneously etched from the top surface of the spray plate 1 to connect the connecting hole 1d and avoid damage to the spray plate 1 due to excessive machining depth of the connecting hole 1d.

[0111] This configuration allows for the simultaneous machining of the connecting hole 1d and the spray window, spray hole 1a, and liquid inlet hole 1c, saving process steps, improving machining efficiency, and reducing machining costs.

[0112] Specifically, during the patterning deposition of electrode structure 4, a conductive ring 7 is simultaneously deposited within the connecting hole 1d to ensure that the conductive ring 7 is connected to the electrode ring 41.

[0113] Specifically, the conductive ring 7 is made of the same material as the lead wire 42 and the electrode ring 41. Furthermore, the conductive ring 7 is manufactured using a deposition process, specifically deposited within the connecting hole 1d. The conductive ring 7 is electrically connected to the lead wire 42.

[0114] This configuration allows for connection to an external flexible circuit board above the spray plate 1, making the form of external voltage more flexible.

[0115] In the description of this application, it should be noted that the terms "upper," "lower," etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application. Unless otherwise expressly specified and limited, the terms "installed," "connected," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication between two elements. For those skilled in the art, the specific meaning of the above terms in this application can be understood according to the specific circumstances.

[0116] It should be noted that in this application, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0117] The above description is merely a specific embodiment of this application, enabling those skilled in the art to understand or implement this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features claimed herein.

Claims

1. A small-diameter current fluid injection chip, characterized in that, It includes: The spraying plate includes an SOI silicon substrate, which sequentially comprises a top silicon layer, a buried oxide layer, and a bottom silicon layer. The bottom surface of the top silicon layer is the bottom surface of the spraying plate, and the top surface of the bottom silicon substrate is the top surface of the spraying plate. Multiple annular grooves are formed on the surface of the top silicon layer to create multiple bosses. The depth of the annular grooves is less than the thickness of the top silicon layer. Coaxial spraying holes are formed on the surfaces of the multiple bosses, and the spraying holes pass through the top silicon layer and the buried oxide layer. Multiple liquid inlet holes are formed on the surface of the bottom silicon layer, and the depth of the liquid inlet holes is the same as the thickness of the bottom silicon layer, so that the spraying holes communicate with the liquid inlet holes. The electrode structure includes multiple electrode rings, each of which is connected to the bottom surface of the spray plate and surrounds multiple annular grooves. There is a potential difference between the electrode rings and the corresponding bosses.

2. The small-diameter current fluid injection chip according to claim 1, characterized in that, It also includes a thickening layer formed on the bottom surface of the spray plate. The thickening layer has multiple connecting grooves on its surface, which are respectively connected to multiple annular grooves and cover the annular grooves. The electrode structure is formed on the bottom surface of the thickening layer.

3. The small-diameter electrofluid injection chip according to claim 2, characterized in that, It also includes a mask layer, which is formed on the thickened layer and the bottom surface of the boss, and the mask layer leaves a plurality of the annular grooves on the surface of the top silicon layer, and the electrode structure is formed on the bottom surface of the mask layer.

4. The small-diameter electrofluid injection chip according to claim 1, characterized in that, The plurality of liquid inlet holes are arranged coaxially with the plurality of annular grooves, and the diameter of the liquid inlet holes is not less than ten times the outer diameter of the annular grooves.

5. The small-diameter current fluid injection chip according to claim 3, characterized in that, The electrode structure also includes multiple leads, each of which is connected to the surface of the mask layer, and each of which is electrically connected to multiple electrode rings and to an external flexible circuit board.

6. The small-diameter electrofluid injection chip according to claim 5, characterized in that, The surface of the spray plate is also provided with multiple connecting holes, and the thickened layer and the mask layer have notches at the positions corresponding to the connecting holes; a conductive ring is arranged in the connecting hole, the bottom of the conductive ring extends to the bottom surface of the mask layer and is electrically connected to the lead wire, and the top of the conductive ring is electrically connected to the external flexible circuit board.

7. The small-diameter electrofluid injection chip according to claim 3, characterized in that, It also includes a passivation layer that covers the electrode ring and the lead surface.

8. The small-diameter electrofluid injection chip according to claim 7, characterized in that, It also includes a hydrophobic layer, which covers the passivation layer and the bottom surface of the mask layer.

9. A method for forming a small-diameter electrofluid jet chip, characterized in that, The method for forming a small-diameter electrohydraulic jet chip as described in any one of claims 1 to 8 includes the following steps: SOI silicon substrates are obtained as spray plates. The SOI silicon substrates consist of a bottom silicon layer, a buried oxide layer, and a top silicon layer from top to bottom. A thickened layer is deposited on the bottom surface of the spray plate; Multiple jetting windows are etched into the bottom surface of the thickened layer to expose the top silicon layer; Multiple jet holes are etched on the bottom surface of the top silicon layer, and the jet holes extend to the bottom surface of the bottom silicon layer. A mask layer is formed on the bottom surface of the thickened layer and the bottom surface of the spray plate. Multiple annular grooves are formed on the bottom surface of the spray plate by etching through the mask to form multiple bosses. The spray holes are coaxial with the bosses. The depth of the annular grooves is less than the thickness of the top silicon layer. Multiple liquid inlet holes are etched on the top surface of the spray plate. Each liquid inlet hole corresponds to a spray hole. The liquid inlet holes are opened to the top surface of the buried oxygen layer to communicate with the spray holes. An electrode structure is patterned on the bottom surface of the mask layer; A passivation layer is deposited on the surface of the electrode structure; A hydrophobic layer is formed on the bottom surface of the passivation layer and the bottom surface of the mask layer.

10. The method for forming a small-diameter electrofluid jet chip according to claim 9, characterized in that, Also includes: Multiple connecting holes are made at the edge of the spray plate, and corresponding notches are made in the mask layer and the thickened layer that communicate with the connecting holes; A conductive ring is deposited and formed within the connecting hole, and the conductive ring extends to connect with the electrode structure.

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