Electrofluid printing chip and forming method thereof

Abstract

The invention relates to an electrofluid printing chip and a forming method thereof, and the electrofluid printing chip comprises a silicon plate and a plurality of annular grooves which are arranged on the silicon plate, the annular grooves are uniformly formed in the bottom surface of the silicon plate, and bosses are formed in the middles of the annular grooves; the plurality of injection holes are respectively formed in the bottom surfaces of the plurality of bosses, and the injection holes penetrate through the silicon plate; the plurality of sinking grooves are formed in the top surface of the silicon plate, the plurality of sinking grooves are in one-to-one correspondence with the plurality of spraying holes, and the spraying holes are communicated with the groove bottoms of the sinking grooves; the sinking groove shortens the depth of the jet hole; the protective layer is arranged on the surface of the silicon plate; and the multiple sets of electrode structures are all arranged at the bottom of the silicon plate, the electrode structures are formed on the protection layer, and the pressure applying ends of the multiple electrode structures are arranged around the multiple annular grooves respectively. The silicon plate is used as the jet plate, the jet holes are formed in a dry etching mode, the precision of the jet holes is higher, and the printing precision is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of inkjet printing, and in particular to an electrohydrodynamic printing chip and a forming method thereof. BACKGROUND

[0002] As an additive manufacturing direct writing technology, inkjet printing has the advantages of no need for masks, flexible production, high material utilization rate, etc., and has a good application prospect in the fields of printed display, printed circuit, printed solar cell, etc. The electrohydrodynamic inkjet printing technology uses electric field force as the main driving force, which greatly enhances the driving ability of the ink, and can print high-viscosity ink. At the same time, since the liquid meniscus locally ejects, the size of the ink droplet produced can be much smaller than the diameter of the nozzle, thereby significantly improving the printing resolution. The electrohydrodynamic inkjet printing technology overcomes the two major shortcomings of traditional inkjet printing technology and has a broad application prospect.

[0003] In the related art, a jet hole is formed on a jet plate, and an electrode ring is arranged at the jet hole, so as to arrange a voltage at each jet hole and achieve independent control of multiple jet holes. A higher voltage is needed to generate an electric field force to make the functional liquid be ejected from the jet hole. Therefore, the jet plate needs to have good high-voltage resistance. Generally, glass is used as the material of the jet plate to meet the pressure resistance requirement.

[0004] However, the jet hole formed on the glass jet plate is usually processed by laser-induced etching, and processes such as photolithography, dry etching, and wet etching with higher precision cannot be used. After the jet hole is processed by the laser-induced etching process, not only the morphology of the processing surface is poor, but also the inner wall morphology of the jet hole is poor, so the diameter consistency of different parts of the jet hole is poor, which will adversely affect the printing accuracy. Especially when a smaller size droplet needs to be printed, the diameter of the jet hole needs to be in the micron level, and the jet hole processed by the laser-induced etching process is basically in an unusable state, so the glass jet plate cannot meet the high-precision jetting requirement. SUMMARY

[0005] Embodiments of the present application provide an electrohydrodynamic printing chip and a forming method thereof to solve the technical problem that the jet hole precision of the glass jet plate in the related art is poor, which adversely affects the printing effect and cannot meet the high-precision printing requirement.

[0006] In a first aspect, an electrohydrodynamic printing chip is provided, comprising: a silicon plate and a plurality of: a plurality of annular grooves, the plurality of annular grooves being evenly formed on the bottom surface of the silicon plate, and a boss being formed at the middle part of the annular groove; a plurality of jet holes, the plurality of jet holes being respectively formed on the bottom surface of the plurality of bosses, and the jet holes penetrating through the silicon plate; a plurality of sinking grooves, each of the plurality of sinking grooves is arranged on the top surface of the silicon plate, and each of the plurality of sinking grooves corresponds to one of the plurality of injection holes, and the injection hole is in communication with the bottom of the sinking groove; the sinking groove shortens the hole depth of the injection hole; a protective layer arranged on the surface of the silicon plate; a plurality of electrode structures, each of the plurality of electrode structures is arranged on the bottom of the silicon plate, the electrode structure is formed on the protective layer, and the pressing end of each of the plurality of electrode structures is arranged around the annular groove.

[0007] In some embodiments, the bottom surface of the boss is higher than the bottom surface of the silicon plate, so as to increase the height difference between the bottom surface of the boss and the pressing end of the electrode structure.

[0008] In some embodiments, the silicon plate comprises an SOI silicon wafer, the SOI silicon wafer comprises a first silicon layer, a buried oxygen layer and a second silicon layer from top to bottom, the annular groove is arranged on the second silicon layer, and the bottom surface of the boss is flush with the bottom surface of the buried oxygen layer.

[0009] In some embodiments, the opening of the sinking groove is arranged in an expanding manner, and the opening of the sinking groove is larger than the hole diameter of the injection hole.

[0010] In some embodiments, the electrode structure comprises an electrode ring and a lead wire, the electrode ring and the lead wire are connected to the protective layer, the electrode ring is arranged around the annular groove, one end of the lead wire is electrically connected to the electrode ring, and the other end of the lead wire is used for electrically connecting to an external flexible circuit board.

[0011] In some embodiments, the bottom surface of the silicon plate further comprises a receiving groove, the receiving groove is arranged close to the edge of the silicon plate, the receiving groove makes the bottom surface of the silicon plate in a stepped manner, and the end of the lead wire away from the electrode ring extends to the bottom of the receiving groove.

[0012] In some embodiments, the fluid printing chip further comprises a passivation layer and a hydrophobic layer, the passivation layer covers the surface of the electrode structure, the hydrophobic layer covers the surface of the passivation layer and the protective layer, and the end of the electrode structure for electrically connecting to the external flexible circuit board is exposed.

[0013] In some embodiments, the protective layer comprises a silicon dioxide layer and a silicon nitride layer.

[0014] The technical scheme provided by the present application has the following beneficial effects: The embodiment of the present application provides a kind of electrofluid printing chip, silicon plate is used as jet plate, silicon plate can be processed jet hole by dry etching process, to ensure the processing precision of jet hole, and micron level aperture processing can be realized, improve printing precision, guarantee printing quality.Jet hole is processed from the jet position of jet hole, the topography state of the orifice of jet hole is better, after functional liquid is ejected, it is not easy to be affected and occur jet direction deflection at the orifice of jet hole, also not easy to appear ink hanging condition, guarantee printing quality.

[0015] The arrangement of annular groove, on the one hand, isolates the boss in the annular groove, avoiding the voltage at different jet holes from being mutually wound, and improving the controllability of printing. On the other hand, the annular groove ensures the stable formation of Taylor cone on the bottom surface of the boss and avoids the functional liquid on the bottom surface of the boss from spreading to the electrode structure, thereby ensuring normal ink ejection.

[0016] The arrangement of the sunken groove shortens the hole depth of the jet hole under the condition of ensuring that the jet hole is small, reduces the aspect ratio of the jet hole, and thus facilitates the processing of the jet hole, avoids the jet hole being too deep to cause paste and scorching during etching, reduces the process processing difficulty, and ensures the processing quality of the jet hole. In addition, the sunken groove is easy to converge the functional liquid, thereby stably supplying ink to the jet hole. The sunken groove supplies ink to the jet hole, which supports the processing of the jet hole with a smaller aperture, thereby meeting the demand for high-precision printing with smaller size.

[0017] In a second aspect, a forming method of an electrofluid printing chip is provided, which is used for forming the electrofluid printing chip as described above, and includes the following steps: obtaining a silicon plate; processing a plurality of annular grooves on the bottom surface of the jet plate to form a plurality of bosses; thinning the bosses so that the bottom surface of the boss is higher than the bottom surface of the jet plate; processing a counterbore on the bottom surface of the boss from bottom to top; opening a plurality of sunken grooves on the top surface of the jet plate, respectively corresponding to the plurality of counterbores, so that the sunken grooves and the counterbores are in communication to form jet holes; forming a protective layer on the surface of the silicon plate; patterning the surface of the protective layer on the bottom surface of the silicon plate to form a plurality of electrode rings and lead wires; depositing a passivation layer on the surface of the electrode ring and the lead wire; forming a hydrophobic layer on the bottom surface of the silicon plate.

[0018] In some embodiments, the silicon plate includes an SOI silicon wafer, and the thinning of the bosses so that the bottom surface of the boss is higher than the bottom surface of the jet plate includes: the bottom surface of the boss is flush with the surface of the buried oxygen layer of the SOI silicon wafer.

[0019] Another embodiment of the present application provides a forming method of the electrofluidic printing chip, since the method is used for forming the electrofluidic printing chip, the beneficial effects of the forming method are consistent with those of the electrofluidic printing chip, which will not be repeated here. BRIEF DESCRIPTION OF DRAWINGS

[0020] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed in the embodiment description will be briefly introduced as follows. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0021] Figure 1 A schematic diagram of the electrofluidic printing chip provided by the embodiment of the present application; Figure 2 A schematic diagram of the SOI silicon wafer provided by the embodiment of the present application; Figure 3 A flowchart of the electrofluidic printing chip forming method provided by another embodiment of the present application.

[0022] In the figure: 1, silicon plate; 1a, annular groove; 1b, boss; 1c, ejection hole; 1d, containing groove; 1e, sunken groove; 11, first silicon layer; 12, buried oxygen layer; 13, second silicon layer; 2, protective layer; 21, silicon dioxide layer; 22, silicon nitride layer; 3, electrode structure; 31, electrode ring; 32, lead wire; 4, passivation layer; 5, hydrophobic layer. DETAILED DESCRIPTION

[0023] In order to make the purpose, technical solutions and advantages of the embodiments of the present application more clear, the technical solutions in the embodiments of the present application will be described clearly and completely in the following with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, not all. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0024] The embodiments of the present application provide an electrofluidic printing chip and a forming method thereof, which uses a silicon plate as an ejection plate and uses a dry etching form to ejection holes, so that the precision of the ejection holes is higher and the printing precision is improved. The present application solves the technical problem that the ejection hole 1c of the glass material ejection plate has poor precision, has adverse effects on the printing effect, and cannot meet the high-precision printing demand in the related art.

[0025] REFERENCE Figure 1The application discloses a kind of electrofluid printing chip, including silicon plate 1 and be arranged on silicon plate 1 multiple annular grooves 1a, multiple ejection holes 1c, protective layer 2, multiple electrode structures 3.Ejection hole 1c is opened in the bottom surface of silicon plate 1, sunken groove 1e is opened in the top surface of silicon plate 1 opposite the position of ejection hole 1c, and sunken groove 1e is communicated with ejection hole 1c.Protective layer 2 covers the surface of silicon plate 1, and electrode structure 3 is located at the bottom of silicon plate 1, which is separated from silicon plate 1 and electrode structure 3 by protective layer 2, and electrode structure 3 includes multiple pressure ends, which are arranged around multiple ejection holes 1c respectively.

[0026] In this way, by applying voltage to the outlet of ejection hole 1c through electrode structure 3, the functional liquid in ejection hole 1c is ejected by using electric field force.The arrangement of protective layer 2 enhances the high-voltage resistance of silicon plate 1, ensuring that silicon plate 1 will not be punctured, thereby ensuring the stability of silicon plate 1 structure and the stability of printing.

[0027] Silicon plate 1 is used as a jet plate, and silicon plate 1 can process ejection hole 1c through dry etching process to ensure the processing accuracy of ejection hole 1c and realize micron-level aperture processing, thereby improving printing accuracy and ensuring printing quality.Ejection hole 1c is processed from the ejection position of ejection hole 1c as the starting point, and the appearance state of the aperture of ejection hole 1c is better.After the functional liquid is ejected, it is not easy to be affected by the aperture of ejection hole 1c and deviate from the ejection direction, and it is also not easy to appear ink hanging, thereby ensuring the printing quality.

[0028] With reference to Figure 1 The arrangement of sunken groove 1e shortens the hole depth of ejection hole 1c, thereby facilitating the processing of ejection hole 1c, avoiding the situation that ejection hole 1c is too deep and appears glue paste and scorching during etching process, reducing the processing difficulty and ensuring the processing quality of ejection hole 1c.In addition, sunken groove 1e is easy to converge functional liquid, thereby stably supplying ink to ejection hole 1c, and supporting the processing of ejection hole 1c with a smaller aperture to adapt to the demand of high-precision printing with smaller size.

[0029] With reference to Figure 1 In this embodiment, annular groove 1a is formed by dry etching.The ejection hole 1c is opened in the bottom surface of the boss 1b.

[0030] By opening annular groove 1a, on the one hand, boss 1b is isolated in annular groove 1a, thereby avoiding the mutual winding of voltages at different ejection holes 1c and improving the controllability of printing.On the other hand, annular groove 1a ensures the stable formation of Taylor cone on the bottom surface of boss 1b, and avoids the spread of functional liquid on the bottom surface of boss 1b to contact electrode structure 3, thereby ensuring normal ink ejection.

[0031] With reference to Figure 1Further, the bottom surface of the boss 1b is higher than the bottom surface of the silicon plate 1, i.e. the boss 1b is located in the annular groove 1a. In this embodiment, the boss 1b is thinned after the annular groove 1a is processed, so that the bottom surface of the boss 1b is higher than the bottom surface of the silicon plate 1. In this embodiment, the boss 1b is thinned by using a dry etching process.

[0032] In this way, by increasing the height of the bottom surface of the boss 1b, in the first aspect, the depth of the ejection hole 1c is shortened, so that the required processing depth of the ejection hole 1c is shortened, and the process difficulty is reduced; in the second aspect, the functional liquid on the bottom surface of the boss 1b is more likely to form a Taylor cone stably, and by pulling apart the height difference between the Taylor cone and the electrode structure 3 in height, the functional liquid is prevented from spreading to the electrode structure 3 and disturbing the electrode structure 3; in the third aspect, the ejection position of the functional liquid and the position of the electrode structure 3 are arranged with a height difference, so that the electric field generated by the electrode structure 3 acts on the functional liquid more stably, and thus the ejection hole 1c is more easily controlled.

[0033] Referring to Figure 1 and Figure 2 In this embodiment, the silicon plate 1 comprises an SOI silicon wafer, and the SOI silicon wafer comprises a multilayer structure. The SOI silicon wafer comprises, from top to bottom, a first silicon layer 11, a buried oxide layer 12, and a second silicon layer 13. The annular groove 1a is formed in the second silicon layer 13, and the bottom surface of the boss 1b is flush with the bottom surface of the buried oxide layer 12.

[0034] In this way, the material of the buried oxide layer 12 is silicon dioxide, and the etching selectivity ratio of silicon dioxide and the silicon layer is different. When the boss 1b is thinned, the second silicon layer 13 is etched away, and at this time, the bottom surface of the boss 1b is the bottom surface of the buried oxide layer 12. Since the buried oxide layer 12 is in a factory state, the flatness of the surface of the buried oxide layer 12 is good, so that the flatness of the ejection surface of the boss 1b is guaranteed, the Taylor cone formed on the surface of the boss 1b is more stable, and the printing quality is improved.

[0035] It should be noted that if the same material is etched and thinned, the surface formed after etching is relatively rough.

[0036] In this embodiment, the sinking groove 1e is formed on the top surface of the silicon plate 1, and in this embodiment, the sinking groove 1e is formed by using a wet etching process.

[0037] In this embodiment, when the ejection hole 1c is processed, the ejection hole 1c does not penetrate the silicon plate 1 after being processed, and penetrates the silicon plate 1 by processing the sinking groove 1e.

[0038] Referring to Figure 1 , specifically, in this embodiment, the slope of the groove wall of the sinking groove 1e is 50-60 degrees. The opening of the sinking groove 1e is arranged in an expanding manner, and the opening of the sinking groove 1e is larger than the diameter of the ejection hole 1c.

[0039] In this way, the sinking groove 1e shortens the hole depth of the ejection hole 1c, thus facilitating the processing of the ejection hole 1c, avoiding the situation that the ejection hole 1c is too deep to cause glue burning during etching, reducing the process processing difficulty, and ensuring the processing quality of the ejection hole 1c. In addition, the sinking groove 1e is easy to converge functional liquid, thus stably supplying ink to the ejection hole 1c. Through the sinking groove 1e, the ejection hole 1c is supplied with ink, and the hole diameter of the ejection hole 1c is processed to be smaller, thus adapting to the demand of high-precision printing of smaller size.

[0040] With reference to Figure 1 Specifically, in the embodiment, the slope of the groove wall of the sinking groove 1e is 50-60 degrees. The slot of the sinking groove 1e is arranged in an expanding manner, and the slot of the sinking groove 1e is larger than the hole diameter of the ejection hole 1c.

[0041] The electrode structure 3 includes an electrode ring 31 and a lead wire 32, both of which are connected to the protective layer 2, and the electrode ring 31 is the pressure applying end of the electrode structure 3. The electrode ring 31 surrounds the annular groove 1a, and one end of the lead wire 32 is electrically connected to the electrode ring 31, and the other end of the lead wire 32 is used to be electrically connected to an external flexible circuit board.

[0042] In this way, after the lead wire 32 is electrically connected to the external flexible circuit board, the electrode ring 31 can be supplied with power through the lead wire 32, and the independent control of different ejection holes 1c can be realized by applying voltage to different electrode rings 31.

[0043] Specifically, the electrode structure 3 is processed by a deposition process. The material of the electrode ring 31 and the lead wire 32 includes one or more of gold, silver, copper, aluminum, and chromium.

[0044] With reference to Figure 1 The bottom surface of the silicon plate 1 is also provided with a containing groove 1d, which is arranged close to the edge of the silicon plate 1, and the containing groove 1d makes the bottom surface of the silicon plate 1 be stepped. The end of the lead wire 32 away from the electrode ring 31 extends to the bottom of the containing groove 1d.

[0045] In this way, the containing groove 1d is processed to leave space for the connection and installation of the flexible circuit board, avoiding the direct packaging of the flexible circuit board on the bottom surface of the silicon plate 1, avoiding the occupation of the space on the bottom surface of the silicon plate 1, and ensuring that the boss 1b can be as close as possible to the substrate to be printed, thus ensuring the adjustment range of the printing height.

[0046] Preferably, after the flexible circuit board is connected to the lead wire 32 in the containing groove 1d, the lowest part of the flexible circuit board is higher than the bottom surface of the silicon plate 1.

[0047] Preferably, the accommodating groove 1d is formed by wet etching, so that the groove wall of the accommodating groove 1d is formed with a slope, and the lead wire 32 is conveniently extended along the groove wall of the accommodating groove 1d to the groove bottom of the accommodating groove 1d. In the embodiment, the slope of the groove wall of the accommodating groove 1d is at 50-80 degrees.

[0048] Further, the depth of the accommodating groove 1d is consistent with the thickness of the second silicon layer 13, and the groove bottom of the accommodating groove 1d is the surface of the buried oxygen layer 12, which ensures the flatness of the groove bottom of the accommodating groove 1d, thereby facilitating the formation of various structures on the surface of the groove bottom.

[0049] Preferably, the protective layer 2 includes a silicon dioxide layer 21 and a silicon nitride layer 22.

[0050] In the embodiment, the silicon dioxide layer 21 is formed on the upper and lower exposed surfaces of the silicon plate 1, and then the silicon nitride layer 22 is formed on the surface of the silicon dioxide layer 21.

[0051] Specifically, the silicon dioxide layer 21 is formed by thermal oxidation growth, and the silicon nitride layer 22 is formed by LPVCD deposition. Preferably, the thickness of the silicon nitride layer 22 and the silicon dioxide layer 21 is 2-10 microns.

[0052] In this way, by forming the silicon dioxide layer 21 and the silicon nitride layer 22 on the surface of the silicon plate 1, the high-pressure resistance of the silicon plate 1 is improved, the shape of the silicon plate 1 is stable, and the printing is ensured to be normal.

[0053] It should be noted that the protective layer 2 covers all the exposed surfaces on the top and bottom of the silicon plate 1.

[0054] Referring to Figure 1 The electrofluidic printing chip further includes a passivation layer 4 and a hydrophobic layer 5. The passivation layer 4 covers the surface of the electrode structure 3. The hydrophobic layer 5 covers the surface of the passivation layer 4 and the protective layer 2. The electrode structure 3 is arranged to expose the end portion for electrical connection with an external flexible circuit board.

[0055] Specifically, in the embodiment, the material of the passivation layer 4 is silicon dioxide, and the passivation layer 4 is patterned on the surface of the electrode ring 31 and the lead wire 32 by spraying glue and metal stripping process to protect the electrode ring 31 and the lead wire 32. In the embodiment, the end portion of the lead wire 32 at the groove bottom of the accommodating groove 1d is not covered by the passivation layer 4, so as to reserve a connection position with the flexible circuit board.

[0056] The material of the hydrophobic layer 5 includes parylene, which is covered on the bottom surface of the silicon plate 1 by a sputtering process to cover the structure of the bottom surface of the silicon plate 1, i.e. the surface of the passivation layer 4, the surface of the protection layer 2, and the surface of the boss 1b. In this embodiment, the end of the lead 32 at the bottom of the accommodating groove 1d is shielded by a mask, and the hydrophobic layer 5 is formed by sputtering. The end of the lead 32 at the bottom of the accommodating groove 1d is not covered by the hydrophobic layer 5 to reserve a connection position with the flexible circuit board.

[0057] In this way, the arrangement of the hydrophobic layer 5 is such that the meniscus of the functional liquid is formed on the jetting surface of the boss 1b, and the overflow of the functional liquid is prevented.

[0058] The embodiment of the present application provides an electrofluidic printing chip, and the silicon plate 1 is used as a jetting plate. The jetting hole 1c can be processed by a dry etching process to ensure the processing precision of the jetting hole 1c and to realize the processing of a micron-level aperture, thereby improving the printing precision and ensuring the printing quality. The jetting hole 1c is processed from the jetting position of the jetting hole 1c as a starting point, and the topography at the aperture of the jetting hole 1c is better. After the functional liquid is jetted, the jetting direction is not easily deflected due to the influence of the aperture of the jetting hole 1c, and the ink hanging phenomenon is not easily caused, thereby ensuring the printing quality.

[0059] The arrangement of the annular groove 1a separates the boss 1b in the annular groove 1a, avoids the mutual winding of voltages at different jetting holes 1c, and improves the controllability of printing. In addition, the annular groove 1a ensures the stable formation of the Taylor cone on the bottom surface of the boss 1b and avoids the functional liquid on the bottom surface of the boss 1b from spreading to the electrode structure 3, thereby ensuring the normal ink jetting.

[0060] The arrangement of the sunken groove 1e shortens the hole depth of the jetting hole 1c, thereby facilitating the processing of the jetting hole 1c, avoiding the overdeep jetting hole 1c from being burnt during the etching process, reducing the process processing difficulty, and ensuring the processing quality of the jetting hole 1c. In addition, the sunken groove 1e is easy to converge the functional liquid, thereby stably supplying the ink to the jetting hole 1c. The ink is supplied to the jetting hole 1c through the sunken groove 1e, and the aperture of the jetting hole 1c is supported to be small, thereby adapting to the high-precision printing demand of a smaller size.

[0061] Referring to Figure 3 Another embodiment of the present application provides a forming method of an electrofluidic printing chip, which is used for forming the electrofluidic printing chip as described above and includes steps S100-S900.

[0062] S100, obtaining a silicon plate 1.

[0063] S200, processing a plurality of annular grooves 1a on the bottom surface of the jetting plate to form a plurality of bosses 1b.

[0064] S300, thinning the boss 1b so that the bottom surface of the boss 1b is higher than the bottom surface of the ejection plate.

[0065] S400, machining a counterbore on the bottom surface of the boss 1b from bottom to top.

[0066] S500, opening a plurality of sunken grooves 1e on the top surface of the ejection plate, each corresponding to a plurality of said counterbores, so that said sunken grooves 1e communicate with said counterbores to form ejection holes 1c.

[0067] S600, sequentially forming a protective layer 2 on the surface of the silicon plate 1.

[0068] S700, patterning the protective layer 2 on the bottom surface of the silicon plate 1 to form a plurality of electrode rings 31 and lead wires 32.

[0069] S800, depositing a passivation layer 4 on the surface of the electrode ring 31 and the lead wire 32.

[0070] S900, forming a hydrophobic layer 5 on the bottom surface of the silicon plate 1.

[0071] In this way, the silicon plate 1 is used as an ejection plate, the ejection holes 1c can be machined by a dry etching process to ensure the machining precision of the ejection holes 1c and to realize the machining of micron-level hole diameters, thereby improving the printing precision and ensuring the printing quality. The ejection holes 1c are machined from the ejection position of the ejection holes 1c as the starting point, and the topography of the ejection holes 1c at the hole opening is better. After the functional liquid is ejected, it is not easy to be affected by the ejection hole 1c at the hole opening and deviate from the ejection direction, nor is it easy to cause ink hanging, thereby ensuring the printing quality.

[0072] In the step S100, the silicon plate 1 is obtained.

[0073] Specifically, in the present embodiment, the silicon plate 1 is selected as the ejection plate, and therefore when the groove hole structure is machined on the silicon plate 1, etching and photolithography processes are suitable to be used to ensure the machining precision. In the present embodiment, the thickness of the silicon plate 1 is 400-800 microns to ensure the strength of the silicon plate 1.

[0074] In the step S200, a plurality of annular grooves 1a are machined on the bottom surface of the ejection plate to form a plurality of bosses 1b.

[0075] Specifically, a plurality of annular grooves 1a are machined on the bottom surface of the silicon plate 1 by a dry etching process to form the bosses 1b. The diameter of the boss 1b is 50-80 microns. According to the opening diameter of the ejection hole 1c, the diameter of the boss 1b is determined, and preferably, the diameter of the boss 1b is 1.5-3 times the diameter of the ejection hole 1c. The ring width of the annular groove 1a is not less than 30 microns.

[0076] In this way, the specific ratio of the diameter of the ejection hole 1c to the diameter of the boss 1b ensures that the functional liquid forms a stable Taylor cone at the bottom surface of the boss 1b, thereby ensuring the printing quality. The limitation of the ring width of the annular groove 1a ensures that the boss 1b is independent, and the functional liquid under the boss 1b is not prone to spread to the bottom surface of the silicon plate 1.

[0077] In the step S300, the boss 1b is thinned so that the bottom surface of the boss 1b is higher than the bottom surface of the ejection plate.

[0078] Specifically, in the embodiment, the silicon plate 1 comprises an SOI silicon wafer, and the boss 1b is thinned so that the bottom surface of the boss 1b is flush with the surface of the buried oxygen layer 12 of the SOI silicon wafer.

[0079] In the embodiment, by increasing the height of the bottom surface of the boss 1b, in the first aspect, the depth of the ejection hole 1c is shortened, thereby reducing the required processing depth of the ejection hole 1c and reducing the process difficulty; in the second aspect, the functional liquid at the bottom surface of the boss 1b is more stable to form a Taylor cone, and by pulling apart the height difference between the Taylor cone and the electrode structure 3, the functional liquid is prevented from spreading to the electrode structure 3 and disturbing the electrode structure 3; in the third aspect, the height difference between the ejection position of the functional liquid and the position of the electrode structure 3 is arranged, and the electric field generated by the electrode structure 3 more stably acts on the functional liquid, thereby making it easier to control the ejection hole 1c.

[0080] The SOI silicon wafer comprises, from top to bottom, a first silicon layer 11, a buried oxygen layer 12, and a second silicon layer 13. When the boss 1b is thinned, the second silicon layer 13 is etched, and at this time, the bottom surface of the boss 1b is the bottom surface of the buried oxygen layer 12. Since the buried oxygen layer 12 is in the factory state, the flatness of the surface of the buried oxygen layer 12 is good, thereby ensuring the flatness of the ejection surface of the boss 1b, the Taylor cone on the surface of the boss 1b is more stable, and the printing quality is improved.

[0081] In the step S400, a counterbore is processed on the bottom surface of the boss 1b from bottom to top.

[0082] Specifically, the counterbore on the bottom surface of the boss 1b is processed by a dry etching process, and the counterbore is in a state before the ejection hole 1c is completely formed. In the embodiment, the depth of the counterbore is 100-150 microns.

[0083] In this way, by processing the ejection hole 1c on the bottom surface of the boss 1b, i.e., first processing the ejection hole 1c from the outlet of the ejection hole 1c, the morphology of the outlet of the ejection hole 1c is better, thereby improving the printing quality. In addition, the depth of the counterbore is controlled within a certain range, thereby reducing the process difficulty and avoiding the situation that the hole depth is too deep and the glue is blocked.

[0084] In step S500, a plurality of subsidence grooves 1e corresponding to the plurality of said counterbores are opened on the top surface of the ejection plate, so that the subsidence grooves 1e are in communication with the counterbores to form the ejection holes 1c.

[0085] Specifically, the subsidence grooves are processed on the top surface of the silicon plate 1 by a wet etching process, so that the counterbores are formed through to form the ejection holes 1c.

[0086] In this way, the subsidence grooves 1e shorten the hole depth of the ejection holes 1c, thus facilitating the processing of the ejection holes 1c, avoiding the situation that the ejection holes 1c are too deep to cause the paste to be burnt during the etching process, reducing the process processing difficulty, and ensuring the processing quality of the ejection holes 1c. In addition, the subsidence grooves 1e are easy to converge functional liquid, thereby stably supplying ink to the ejection holes 1c. By supplying ink to the ejection holes 1c through the subsidence grooves 1e, the hole diameter of the ejection holes 1c can be processed to be smaller, which is suitable for smaller size high-precision printing requirements.

[0087] Further, the slope of the groove wall of the subsidence groove 1e is 50-60 degrees. The groove opening of the subsidence groove 1e is arranged in an expanding manner, and the groove opening of the subsidence groove 1e is larger than the hole diameter of the ejection hole 1c. It is convenient to converge functional liquid.

[0088] In this embodiment, the subsidence groove 1e is formed at the same time as the accommodation groove 1d is wet etched on the bottom surface of the silicon plate 1.

[0089] The accommodation groove 1d is wet etched, so that the groove wall of the accommodation groove 1d forms a slope, and the lead wire 32 extends along the groove wall of the accommodation groove 1d to the groove bottom of the accommodation groove 1d. In this embodiment, the groove wall slope of the accommodation groove 1d is 50-80 degrees.

[0090] Further, the depth of the accommodation groove 1d is consistent with the thickness of the second silicon layer 13, and the groove bottom of the accommodation groove 1d is the surface of the buried oxygen layer 12, which ensures the flatness of the groove bottom of the accommodation groove 1d, thereby facilitating the formation of structures on the surface of the groove bottom.

[0091] Since the subsidence groove 1e and the accommodation groove 1d are formed at the same time, the process steps are saved, and the processing efficiency is improved.

[0092] In step S600, the protective layer 2 is formed on the surface of the silicon plate 1.

[0093] Specifically, a silicon dioxide layer 21 is first formed on the upper and lower exposed surfaces of the silicon plate 1, and then a silicon nitride layer 22 is formed on the surface of the silicon dioxide layer 21.

[0094] Specifically, the silicon dioxide layer 21 is formed by a thermal oxidation growth process, and the silicon nitride layer 22 is formed by an LPVCD deposition process. Preferably, the thickness of the silicon nitride layer 22 and the silicon dioxide layer 21 is 2-10 microns.

[0095] In this way, the high-pressure resistance of the silicon plate 1 is improved by forming the silicon dioxide layer 21 and the silicon nitride layer 22 on the surface of the silicon plate 1, the shape of the silicon plate 1 is stable, and the printing is ensured to be normally performed.

[0096] It should be noted that the protective layer 2 covers all exposed surfaces on the top and bottom of the silicon plate 1.

[0097] In step S700, the plurality of electrode rings 31 and the plurality of lead wires 32 are patterned on the surface of the protective layer 2 on the bottom of the silicon plate 1.

[0098] Specifically, the electrode structure 3 is processed by a deposition process. The material of the electrode rings 31 and the lead wires 32 includes one or more of gold, silver, copper, aluminum, and chromium. One end of the lead wire 32 extends into the accommodating groove 1d along the bottom of the silicon plate 1 and the groove wall of the accommodating groove 1d.

[0099] In this way, the accommodating groove 1d is processed to leave space for the connection and installation of the flexible circuit board, so as to avoid the flexible circuit board being directly packaged on the bottom of the silicon plate 1, to avoid occupying the space on the bottom of the silicon plate 1, to ensure that the boss 1b can be as close as possible to the substrate to be printed, and to ensure the adjustment range of the printing height.

[0100] Preferably, after the flexible circuit board is connected to the lead wire 32 in the accommodating groove 1d, the lowest part of the flexible circuit board is higher than the bottom of the silicon plate 1.

[0101] In step S800, the passivation layer 4 is deposited on the surface of the electrode rings 31 and the lead wires 32.

[0102] Specifically, the passivation layer 4 is deposited on the surface of the electrode rings 31 and the lead wires 32. The passivation layer 4 is preferably silicon dioxide, and the thickness of the passivation layer 4 is preferably 300-500 nanometers. The passivation layer 4 is covered on the surface of the electrode rings 31 and the lead wires 32 by using a glue spraying and metal stripping process to protect the electrode rings 31 and the lead wires 32. In this embodiment, the end of the lead wire 32 at the bottom of the accommodating groove 1d is not covered by the passivation layer 4, so as to reserve a connection position with the flexible circuit board.

[0103] In step S900, the hydrophobic layer 5 is formed on the bottom surface of the silicon plate 1.

[0104] Specifically, the material of the hydrophobic layer 5 includes parylene, which is covered on the bottom of the silicon plate 1 by a sputtering process to cover the structure of the bottom of the silicon plate 1, i.e., the surface of the passivation layer 4, the surface of the protective layer 2, and the surface of the boss 1b. Preferably, the thickness of the hydrophobic layer 5 includes 1-5 micrometers. In this embodiment, the end of the lead wire 32 at the bottom of the accommodating groove 1d is shielded by a mask, and the hydrophobic layer 5 is formed by sputtering.

[0105] In this way, the hydrophobic layer 5 is arranged so that the functional liquid forms a meniscus on the ejection surface of the boss 1b, preventing the functional liquid from overflowing.

[0106] In the description of the present application, it should be noted that the terms "upper", "lower", and the like indicate the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application. Unless otherwise expressly specified and limited, the terms "mounting", "connection", "connection" should be broadly understood, for example, it can be fixedly connected, or it can be detachably connected, or integrally connected; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium; it can be the internal communication of two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0107] It should be noted that in the present application, relational terms such as "first" and "second" and the like are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply that there is any such actual relationship or order between these entities or operations. Moreover, the terms "include", "contain" or any other variant thereof are intended to cover non-exclusive inclusion, so that the process, method, article or device including a series of elements not only includes those elements, but also includes other elements not explicitly listed or inherent to such process, method, article or device. Without more limitations, the element defined by the sentence "including a" does not exclude the presence of other identical elements in the process, method, article or device including the element.

[0108] The above is only a specific embodiment of the present application, which enables those skilled in the art to understand or implement the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to these embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features applied herein.

Claims

1. A current-current printed chip, characterized in that, It includes: Silicon substrate and the following on the silicon substrate: Multiple annular grooves are evenly formed on the bottom surface of the silicon substrate, and a boss is formed in the middle of each annular groove. Multiple injection holes are provided, each of which is located on the bottom surface of a plurality of protrusions and penetrates the silicon substrate. Multiple sinking grooves are formed on the top surface of the silicon substrate, and each sinking groove corresponds to a spray hole. The spray holes are connected to the bottom of the sinking grooves. The sinking grooves shorten the depth of the spray holes. A protective layer is disposed on the surface of the silicon substrate; Multiple sets of electrode structures are arranged on the bottom of the silicon substrate. The electrode structures are formed on the protective layer, and the pressure-applying ends of the multiple electrode structures are arranged around the multiple annular grooves.

2. The electrofluid printed chip according to claim 1, characterized in that, The bottom surface of the boss is higher than the bottom surface of the silicon plate to increase the height difference between the bottom surface of the boss and the pressure end of the electrode structure.

3. The electrofluid printed chip according to claim 2, characterized in that, The silicon substrate includes an SOI silicon wafer, which includes a first silicon layer, a buried oxide layer and a second silicon layer from top to bottom. The annular groove is formed in the second silicon layer, and the bottom surface of the boss is flush with the bottom surface of the buried oxide layer.

4. The electrofluid printed chip according to claim 1, characterized in that, The opening of the sinking trough is flared, and the opening of the sinking trough is larger than the diameter of the injection hole.

5. The electrofluid printed chip according to claim 1, characterized in that, The electrode structure includes an electrode ring and a lead wire. Both the electrode ring and the lead wire are connected to the protective layer. The electrode ring surrounds the annular groove. One end of the lead wire is electrically connected to the electrode ring, and the other end of the lead wire is used for electrical connection to an external flexible circuit board.

6. The electrofluid printed chip according to claim 5, characterized in that, The bottom surface of the silicon plate is also provided with a receiving groove, which is arranged near the edge of the silicon plate, and the receiving groove makes the bottom surface of the silicon plate step-shaped; the end of the lead wire away from the electrode ring extends to the bottom of the receiving groove.

7. The electrofluid printed chip according to claim 1, characterized in that, It also includes a passivation layer and a hydrophobic layer, wherein the passivation layer covers the surface of the electrode structure; and the hydrophobic layer covers the surfaces of the passivation layer and the protective layer. The electrode structure is arranged with exposed ends for electrical connection to an external flexible circuit board.

8. The electrofluid printed chip according to claim 1, characterized in that, The protective layer includes a silicon dioxide layer and a silicon nitride layer.

9. A method for forming an electrofluid printed chip, used to form an electrofluid printed chip as described in any one of claims 1 to 8, characterized in that, Includes the following steps: Obtain silicon wafers; Multiple annular grooves are machined on the bottom surface of the spray plate to form multiple bosses; The boss is thinned so that the bottom surface of the boss is higher than the bottom surface of the spray plate; A countersunk hole is machined from bottom to top on the bottom surface of the boss; Multiple recessed grooves are formed on the top surface of the spray plate, each corresponding to one of the multiple recessed holes, so that the recessed grooves are connected to the recessed holes to form spray holes; A protective layer is formed on the surface of the silicon substrate; Multiple sets of electrode rings and leads are patterned on the protective layer surface on the bottom of the silicon substrate; A passivation layer is deposited on the electrode ring and lead surface; A hydrophobic layer is formed on the bottom surface of the silicon substrate.

10. The method for forming an electrofluid printed chip according to claim 9, characterized in that, The silicon substrate includes an SOI silicon wafer, and the thinning process boss, such that the bottom surface of the boss is higher than the bottom surface of the spray plate, includes: The bottom surface of the boss is flush with the surface of the buried oxide layer of the SOI silicon wafer.

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