Preparation method and application of conducting layer

Abstract

The invention belongs to the field of electronic component preparation, and particularly relates to a preparation method and application of a conducting layer. The preparation method comprises the following steps: coating a substrate with photosensitive conductive silver paste, exposing, developing, and forming a conductive layer on the substrate; the developing step comprises a step S11, and the step S11 is as follows: a nozzle A arranged in the two-fluid developing area sprays a developing solution A for developing through the two-fluid developing area; the developing solution A contains gas and liquid, the liquid is a solution containing at least one solute selected from alkaline inorganic salt and organic alkali, and the volume percentage of the liquid in the developing solution A is 40-99%. According to the preparation method, developing is carried out through the two fluid developing areas, the developing solution A can be atomized, extremely small developing solution A particles can be formed, the developing solution A particles can penetrate into the bottoms of lines with small line spacing, the resolution ratio of the developing lines is improved, the developing solution A can be evenly distributed on the substrate after atomization, excessive developing is avoided, and the developing uniformity is improved.

Description

Technical Field

[0001] This invention belongs to the field of electronic component fabrication, specifically relating to a method for preparing a conductive layer and its application. Background Technology

[0002] In recent years, the demand for miniaturization of surface-mount inductors has been increasing, leading to ever-higher requirements for the precision of the line width and spacing of their internal coils. Currently, photosensitive conductive silver paste technology can achieve coil patterns with a line width and spacing of 15μm. However, when pursuing even smaller line spacing (e.g., <10μm), traditional development methods (i.e., one-fluid development, where the developer is a pure liquid) face challenges. Their main limitations are: the developer used in traditional pump-pressure spray development has a relatively large particle size (>200μm), making it difficult to effectively penetrate to the bottom of the silver paste pattern under vertical spray conditions, resulting in incomplete development; simultaneously, the high flow resistance of the developer between fine line spacings easily causes localized stagnation, leading to decreased development accuracy and poor appearance. Summary of the Invention

[0003] In order to overcome at least one of the technical problems existing in the prior art, one of the objectives of the present invention is to provide a method for preparing a conductive layer. The method introduces gas into the developer A in the two-fluid developing zone to atomize the developer A, reduce the particle size of the developer A, thereby forming a conductive layer with extremely fine lines suitable for inductors. At the same time, it can improve the concentration of the line width of the conductive layer, and further improve the concentration of the inductance value and the quality factor Q value of the inductor containing the conductive layer.

[0004] A second objective of this invention is to provide an inductor having a concentrated inductance value and a high quality factor Q.

[0005] The third objective of this invention is to provide a method for manufacturing an inductor.

[0006] The fourth objective of this invention is to provide the application of the above-mentioned method for preparing the conductive layer or the above-mentioned method for preparing the inductor in the manufacture of electronic products.

[0007] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0008] The first aspect of the present invention provides a method for preparing a conductive layer, comprising the following steps:

[0009] A photosensitive conductive silver paste is coated onto a substrate, exposed, and developed to form a conductive layer on the substrate.

[0010] The development process includes step S11, which involves: developing by spraying developing solution A through a nozzle A located in the two-fluid developing zone.

[0011] The developer A contains gas and liquid, wherein the liquid is a solution containing at least one solute selected from alkaline inorganic salts and organic bases, and the volume percentage of liquid in the developer A is 40-99%.

[0012] In some embodiments of the present invention, the photosensitive conductive silver paste comprises the following components in parts by weight: 75-90 parts Ag powder, 5-13 parts PMMA resin, 0.3-0.8 parts initiator, 2.3-3.8 parts solvent, and 0.4-0.8 parts dispersant.

[0013] In some embodiments of the present invention, the initiator in the photosensitive conductive silver paste includes at least one of triphenylphosphine oxide, benzoin methyl ether, 2-hydroxy-2-methyl-1-phenyl-1-propanone, 1-hydroxycyclohexylphenyl ketone, 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, and phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide.

[0014] In some embodiments of the present invention, the solvent in the photosensitive conductive silver paste includes at least one of diethylene glycol butyl ether, isopropanol, ethylene glycol methyl ether, ethyl acetate, propylene glycol methyl ether acetate, methyl ethyl ketone, and N-methylpyrrolidone.

[0015] In some embodiments of the present invention, the dispersant in the photosensitive conductive silver paste includes at least one of polyvinyl alcohol, polyvinylpyrrolidone, polyethylene glycol, sodium dodecylbenzenesulfonate, sodium oleate, superdispersant BYK-110, and polyoxyethylene ethers.

[0016] In some embodiments of the present invention, the polyoxyethylene ether dispersant in the photosensitive conductive silver paste is selected from at least one of the Span series dispersants and the Tween series dispersants.

[0017] In some embodiments of the present invention, the volume percentage of liquid in developer A is any value or a range formed by any two of 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, and 99%; in some preferred embodiments of the present invention, the volume percentage of liquid in developer A is 50-99%. When the volume percentage of liquid and gas in developer A is higher than 99%, the entire developing process will exhibit a fluid-like developing state, and developer A cannot form sufficiently small droplets to enter the narrower line spacing to complete the development of extremely fine lines. When the volume percentage of liquid and gas in developer A is lower than 40%, the developing process exhibits a higher air content, which may be able to complete the development of lines, but the developing speed will be slower, and in extreme cases, the pattern may not even be developed.

[0018] In some embodiments of the present invention, the throughput speed through the two-fluid developing zone is 0.3–4.5 m / min; in some embodiments of the present invention, the throughput speed through the two-fluid developing zone is 0.3 m / min, 0.5 m / min, 0.8 m / min, 1.0 m / min, 1.2 m / min, 1.4 m / min, 1.5 m / min, 1.6 m / min, 1.8 m / min, 2.0 m / min, 2.2 m / min, 2.4 m / min, 2.5 m / min, 2.6 m / min, 2.8 m / min, 3.0 m / min, 3.2 m / min, 3.4 m / min, 3… The speed is any value or a range formed by any two of the following: 0.5 m / min, 3.6 m / min, 3.8 m / min, 4.0 m / min, 4.2 m / min, 4.4 m / min, and 4.5 m / min. In some preferred embodiments of the present invention, the passing speed through the two-fluid developing zone is 0.5 to 3.5 m / min. When the passing speed is too fast, the developer A will not be rinsed thoroughly, and some uncured photosensitive conductive silver paste will remain on the substrate. When the passing speed is too slow, the lines on the substrate will have defects such as jagged edges, decreased line width uniformity, increased line cross-sectional taper, and reduced line thickness. In extreme cases, the pattern may even be completely lost due to overdevelopment.

[0019] In some embodiments of the present invention, the spray pressure of the developer A is 0.05–0.25 MPa; in some embodiments of the present invention, the spray pressure of the developer A is any value or a range formed by any two of 0.05 MPa, 0.08 MPa, 0.1 MPa, 0.12 MPa, 0.14 MPa, 0.15 MPa, 0.16 MPa, 0.18 MPa, 0.2 MPa, 0.22 MPa, 0.24 MPa, and 0.25 MPa; in some preferred embodiments of the present invention, the spray pressure of the developer A is 0.1–0.2 MPa. When the spray pressure is too high, the development state of the substrate is consistent with that when the throughput speed is slow. When the spray pressure is too low, the development state of the substrate is consistent with that when the throughput speed is fast, resulting in residual development.

[0020] In some embodiments of the present invention, the temperature of the developer A is 20–40°C; in some embodiments of the present invention, the temperature of the developer A is any value or a range formed by any two of the following: 20°C, 21°C, 22°C, 23°C, 24°C, 25°C, 26°C, 27°C, 28°C, 29°C, 30°C, 31°C, 32°C, 33°C, 34°C, 35°C, 36°C, 37°C, 38°C, 39°C, and 40°C; in some preferred embodiments of the present invention, the temperature of the developer A is 22–26°C. When the temperature of the developer A is too high, the solubility of the developer A in the photosensitive material on the substrate increases, the development time is shortened, which may lead to overdevelopment and affect the uniformity of the line width and line thickness on the substrate. When the temperature of the developer A is too low, the solubility also decreases, the development speed slows down, and the development time is prolonged; in extreme cases, it may be impossible to develop at all.

[0021] In some embodiments of the present invention, the alkaline inorganic salt in the liquid is selected from at least one of sodium carbonate, potassium carbonate, ammonium carbonate, sodium bicarbonate, potassium bicarbonate, ammonium bicarbonate, sodium sulfite, sodium phosphate, sodium aluminate, sodium hypochlorite, and calcium hypochlorite.

[0022] In some embodiments of the present invention, the organic base in the liquid is selected from at least one of triethylamine, sodium methoxide, potassium ethoxide, and potassium tert-butoxide.

[0023] In some embodiments of the present invention, the solvent in the liquid is water.

[0024] In some embodiments of the present invention, the developer A contains a solute with a mass percentage of 0.2% to 2%; in some embodiments of the present invention, the mass percentage of the solute in the liquid is any value or a range formed by any combination of 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1.0%, 1.1%, 1.2%, 1.3%, 1.4%, 1.5%, 1.6%, 1.7%, 1.8%, 1.9%, and 2.0%.

[0025] In some preferred embodiments of the present invention, the liquid is an aqueous solution of sodium carbonate; in some preferred embodiments of the present invention, the aqueous solution of sodium carbonate contains 0.5% to 1.5% sodium carbonate by mass. When the mass concentration of the aqueous solution of sodium carbonate is too low, the pH value of the developer A is low, which prevents the unreacted photosensitive substances in the substrate from forming salts and dissolving, resulting in uneven development or failure to develop. At the same time, if the mass concentration of sodium carbonate in the developer A is too low, it cannot form a buffer solution of bicarbonate ions, leading to a sharp decrease in pH fluctuation and making it difficult to guarantee the stability of the development process. When the mass concentration of sodium carbonate is too high, the pH of the developer A is too high, the reaction rate is extremely fast, and it is very easy to cause local overdevelopment, resulting in a significant reduction in the uniformity of line width and line thickness on the substrate.

[0026] In some embodiments of the present invention, the gas is selected from at least one of compressed air and compressed inert gas. The present invention selects compressed air and / or compressed inert gas as the gas to provide a certain pressure for the spraying of developer A, enabling developer A to be fully atomized.

[0027] In some embodiments of the present invention, the compressed inert gas is selected from at least one of compressed nitrogen, compressed argon, and compressed helium.

[0028] In some embodiments of the present invention, the length of the two-fluid developing area is 180-220 mm; in some embodiments of the present invention, the length of the two-fluid developing area is any value of 180 mm, 185 mm, 190 mm, 195 mm, 200 mm, 205 mm, 210 mm, 215 mm, 220 mm, or a range formed by any two of these values.

[0029] In some embodiments of the present invention, the oscillation frequency of the printhead A is 10–40 Hz; in some embodiments of the present invention, the oscillation frequency of the printhead A is any value or a range formed by any two of the following: 10 Hz, 12 Hz, 14 Hz, 15 Hz, 16 Hz, 18 Hz, 20 Hz, 22 Hz, 24 Hz, 25 Hz, 26 Hz, 28 Hz, 30 Hz, 32 Hz, 34 Hz, 35 Hz, 36 Hz, 38 Hz, and 40 Hz; in some preferred embodiments of the present invention, the oscillation frequency of the printhead A is 20–30 Hz; in some preferred embodiments of the present invention, the oscillation frequency of the printhead A is 20–25 Hz. When the oscillation frequency of the printhead A is too fast, it may cause the spray path of the printhead A to deviate, affecting the uniformity of the developing pressure; at the same time, if the residence time of the developer A at each position is too short, it will also cause a reduction in the impact force of the developing process, and the time for the pattern to develop will be prolonged, which may cause a reduction in uniformity. When the oscillation frequency is too slow, it will affect the uniformity of the developed lines. There is a certain interval between nozzles A and A. When the oscillation frequency is slow, it means that nozzle A will stay in one place for a longer time. However, the substrate is moving forward at a constant speed at this time, which causes the rinsing time to differ between areas of the substrate. The line width and line thickness of different areas on the substrate will have obvious differences.

[0030] In some embodiments of the present invention, the number of nozzles A is 2 to 4; in some embodiments of the present invention, the number of nozzles A is 2, 3 or 4.

[0031] In some embodiments of the present invention, the developing process further includes step S12, which precedes step S11. Step S12 involves spraying developing solution B through a nozzle B disposed in a one-fluid developing zone. The developing solution B is a solution containing at least one solute selected from alkaline inorganic salts and organic bases. Because the impact force of developing solution A is smaller during two-fluid developing, the pattern of the coil conductor in the conductive layer is better. However, two-fluid developing takes longer. By combining the one-fluid developing zone and the two-fluid developing zone, the one-fluid developing zone can quickly develop the pattern, and the two-fluid developing zone can further refine the conductive pattern in the conductive layer, greatly improving the developing efficiency.

[0032] In some embodiments of the present invention, the alkaline inorganic salt in developer B is selected from at least one of sodium carbonate, potassium carbonate, ammonium carbonate, sodium bicarbonate, potassium bicarbonate, ammonium bicarbonate, sodium sulfite, sodium phosphate, sodium aluminate, sodium hypochlorite, and calcium hypochlorite.

[0033] In some embodiments of the present invention, the organic base in developer B is selected from at least one of triethylamine, sodium methoxide, potassium ethoxide, and potassium tert-butoxide.

[0034] In some embodiments of the present invention, the solvent in developer B is water.

[0035] In some embodiments of the present invention, the developer B contains a solute with a mass percentage of 0.05% to 1%. In some embodiments of the present invention, the mass percentage of the solute in the developer B is any value or a range formed by any combination of 0.05%, 0.1%, 0.15%, 0.2%, 0.25%, 0.3%, 0.35%, 0.4%, 0.45%, 0.5%, 0.55%, 0.6%, 0.65%, 0.7%, 0.75%, 0.8%, 0.85%, 0.9%, 0.95%, and 1%.

[0036] In some embodiments of the present invention, the developer B is an aqueous solution of sodium carbonate. In some embodiments of the present invention, the aqueous solution of sodium carbonate in the developer B contains 0.05% to 1% sodium carbonate by mass; in some preferred embodiments of the present invention, the aqueous solution of sodium carbonate in the developer B contains 0.1% to 0.8% sodium carbonate by mass.

[0037] In some preferred embodiments of the present invention, when the developing process further includes step S12, the throughput speed through the two-fluid developing zone is 2 to 3.5 m / min.

[0038] In some preferred embodiments of the present invention, when the developing process further includes step S12, the spray pressure of the developing solution A is 0.13 to 0.15 MPa.

[0039] In some embodiments of the present invention, the length of the fluid developing region is 600-750 mm; in some embodiments of the present invention, the length of the fluid developing region is any value of 600 mm, 610 mm, 620 mm, 630 mm, 640 mm, 650 mm, 660 mm, 670 mm, 680 mm, 690 mm, 700 mm, 710 mm, 720 mm, 730 mm, 740 mm, 750 mm, or a range formed by any two of these values.

[0040] In some embodiments of the present invention, the number of nozzles B is 6 to 10; in some embodiments of the present invention, the number of nozzles B is any value of 6, 7, 8, 9, or 10, or a range formed by any two of them.

[0041] In some embodiments of the present invention, the oscillation frequency of the nozzle B is 10-40 Hz; in some embodiments of the present invention, the oscillation frequency of the nozzle B is any value or a range formed by any two of 10 Hz, 12 Hz, 14 Hz, 15 Hz, 16 Hz, 18 Hz, 20 Hz, 22 Hz, 24 Hz, 25 Hz, 26 Hz, 28 Hz, 30 Hz, 32 Hz, 34 Hz, 35 Hz, 36 Hz, 38 Hz, and 40 Hz; in some preferred embodiments of the present invention, the oscillation frequency of the nozzle B is 20-30 Hz.

[0042] In some embodiments of the present invention, the throughput speed through the fluid developing zone is 1 to 6 m / min; in some embodiments of the present invention, the throughput speed through the fluid developing zone is any value or a range formed by any two of the following: 1 m / min, 1.5 m / min, 2 m / min, 2.5 m / min, 3 m / min, 3.5 m / min, 4 m / min, 4.5 m / min, 5 m / min, 5.5 m / min, and 6 m / min; in some preferred embodiments of the present invention, the throughput speed through the fluid developing zone is 2 to 4.5 m / min.

[0043] In some embodiments of the present invention, the spray pressure of the developer B is 0.05–0.4 MPa; in some embodiments of the present invention, the spray pressure of the developer B is any value or a range formed by any two of the following: 0.05 MPa, 0.08 MPa, 0.1 MPa, 0.12 MPa, 0.14 MPa, 0.15 MPa, 0.16 MPa, 0.18 MPa, 0.2 MPa, 0.22 MPa, 0.24 MPa, 0.25 MPa, 0.26 MPa, 0.28 MPa, 0.3 MPa, 0.32 MPa, 0.34 MPa, 0.35 MPa, 0.36 MPa, 0.38 MPa, and 0.4 MPa; in some preferred embodiments of the present invention, the spray pressure of the developer B is 0.1–0.25 MPa.

[0044] In some embodiments of the present invention, the temperature of the developer B is 10–35°C; in some embodiments of the present invention, the temperature of the developer B is any value or a range formed by any two of the following: 10°C, 11°C, 12°C, 13°C, 14°C, 15°C, 16°C, 17°C, 18°C, 19°C, 20°C, 21°C, 22°C, 23°C, 24°C, 25°C, 26°C, 27°C, 28°C, 29°C, 30°C, 31°C, 32°C, 33°C, 34°C, and 35°C; in some preferred embodiments of the present invention, the temperature of the developer B is 20–26°C.

[0045] In some embodiments of the present invention, the thickness of the conductive layer is 15 to 20 μm; in some embodiments of the present invention, the thickness of the conductive layer is any value of 15 μm, 16 μm, 17 μm, 18 μm, 19 μm, 20 μm or a range formed by any two of them.

[0046] In some embodiments of the present invention, the conductive layer includes a conductive coil; in some embodiments of the present invention, the conductive layer includes a conductive coil and a terminal.

[0047] In some embodiments of the present invention, the exposure step is as follows: a photomask is placed over a substrate coated with photosensitive conductive silver paste, and then exposed to a light source.

[0048] In some embodiments of the present invention, the line width of the mask is 5 to 10 μm; in some embodiments of the present invention, the line width of the mask is any value of 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, 10 μm or a range formed by any two of them.

[0049] In some embodiments of the present invention, the line spacing of the mask is 10 to 15 μm; in some embodiments of the present invention, the line spacing of the mask is any value of 10 μm, 11 μm, 12 μm, 13 μm, 14 μm, 15 μm or a range formed by any two of them.

[0050] In some embodiments of the present invention, the wavelength of the light source is 345-385nm; in some embodiments of the present invention, the wavelength of the light source is any value of 345nm, 350nm, 355nm, 360nm, 365nm, 370nm, 375nm, 380nm, 385nm or a range formed by any two of them.

[0051] In some embodiments of the present invention, the exposure time is 5 to 20 seconds; in some embodiments of the present invention, the exposure time is any value of 5 seconds, 6 seconds, 7 seconds, 8 seconds, 9 seconds, 10 seconds, 11 seconds, 12 seconds, 13 seconds, 14 seconds, 15 seconds, 16 seconds, 17 seconds, 18 seconds, 19 seconds, 20 seconds, or a range formed by any two of these values.

[0052] In some embodiments of the present invention, the substrate is formed by coating a photosensitive ceramic paste onto the surface of a carrier plate and drying it to form an unsintered dielectric green layer.

[0053] In some embodiments of the present invention, the substrate is a ceramic substrate.

[0054] In some embodiments of the present invention, the carrier plate is a glass fiber board.

[0055] In some embodiments of the present invention, the photosensitive ceramic paste comprises the following components in parts by weight: 50-55 parts of inorganic powder, 34-40 parts of PMMA resin, 0.3-0.8 parts of initiator, 3-9 parts of solvent, and 0.3-1.2 parts of dispersant.

[0056] In some embodiments of the present invention, the inorganic powder comprises the following components by mass percentage: 23-28 parts alumina, 50-59 parts silicon dioxide, 6-10 parts boron oxide, and 3-7 parts potassium oxide.

[0057] In some embodiments of the present invention, the initiator in the photosensitive ceramic paste includes at least one of triphenylphosphine oxide, benzoin methyl ether, 2-hydroxy-2-methyl-1-phenyl-1-propanone, 1-hydroxycyclohexylphenyl ketone, 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, and phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide.

[0058] In some embodiments of the present invention, the solvent in the photosensitive ceramic paste includes at least one of diethylene glycol butyl ether, isopropanol, ethylene glycol methyl ether, ethyl acetate, propylene glycol methyl ether acetate, methyl ethyl ketone, and N-methylpyrrolidone.

[0059] In some embodiments of the present invention, the dispersant in the photosensitive ceramic paste includes at least one of polyvinyl alcohol, polyvinylpyrrolidone, polyethylene glycol, sodium dodecylbenzenesulfonate, sodium oleate, superdispersant BYK-110, and polyoxyethylene ethers.

[0060] In some embodiments of the present invention, the polyoxyethylene ether dispersant in the photosensitive ceramic paste is selected from at least one of the Span series dispersants and the Tween series dispersants.

[0061] In some embodiments of the present invention, the initiator in the photosensitive ceramic paste includes triphenylphosphine oxide.

[0062] In some embodiments of the present invention, the solvent in the photosensitive ceramic paste includes diethylene glycol butyl ether.

[0063] In some embodiments of the present invention, the thickness of the substrate is 5 to 25 μm.

[0064] In some embodiments of the present invention, the coating is performed using any one of printing, casting, or roll coating.

[0065] In some embodiments of the present invention, the conductive layer is prepared by coating a substrate with photosensitive conductive silver paste, drying it, exposing it through a mask, developing it, and washing it with water to form a patterned silver conductor structure.

[0066] In some embodiments of the present invention, the drying temperature is 55 to 80°C; in some embodiments of the present invention, the drying temperature is any value of 55°C, 60°C, 65°C, 70°C, 75°C, 80°C, or a range formed by any two of them.

[0067] In some embodiments of the present invention, the drying time is 5 to 30 minutes; in some embodiments of the present invention, the drying time is any value of 5 minutes, 10 minutes, 15 minutes, 20 minutes, 25 minutes, 30 minutes, or a range formed by any two of them.

[0068] In some embodiments of the present invention, the spraying shapes of developer A and developer B are both cone-shaped.

[0069] A second aspect of the present invention provides an inductor comprising a conductive layer prepared by the preparation method described in the first aspect of the present invention.

[0070] A third aspect of the present invention provides a method for fabricating the inductor described in the second aspect of the present invention, comprising the following steps:

[0071] (1) The conductive layer is prepared using the preparation method described in the first aspect of the present invention;

[0072] (2) Coat the conductive layer with photosensitive ceramic paste, expose, develop, and form a ceramic layer;

[0073] (3) According to the structure of the inductor, the conductive layer and the ceramic layer are prepared in sequence on the ceramic layer, and then fired and electroplated to obtain the inductor.

[0074] In this invention, the development of the ceramic paste on the conductive layer can be carried out using development methods commonly used in the prior art, such as one-fluid development.

[0075] In some embodiments of the present invention, the exposure in step (2) is achieved by covering the light source with a mask.

[0076] In some embodiments of the present invention, the wavelength of the light source in step (2) is 345-385nm; in some embodiments of the present invention, the wavelength of the light source in step (2) is any value of 345nm, 350nm, 355nm, 360nm, 365nm, 370nm, 375nm, 380nm, 385nm or any range formed by both.

[0077] In some embodiments of the present invention, the exposure time in step (2) is 1 to 10 s; in some embodiments of the present invention, the exposure time is any value of 1 s, 2 s, 3 s, 4 s, 5 s, 6 s, 7 s, 8 s, 9 s, 10 s or a range formed by any two of them.

[0078] In some embodiments of the present invention, the firing temperature in step (3) is 850-900°C; in some embodiments of the present invention, the firing temperature in step (3) is any value of 850°C, 860°C, 870°C, 880°C, 890°C, 900°C or a range formed by any two of them.

[0079] In some embodiments of the present invention, the holding time for firing in step (3) is 20 min to 120 min; in some embodiments of the present invention, the holding time for firing in step (3) is any value of 20 min, 30 min, 40 min, 50 min, 60 min, 70 min, 80 min, 90 min, 100 min, 110 min, 120 min or a range formed by any two of these values.

[0080] In some embodiments of the present invention, the firing atmosphere in step (3) is air.

[0081] In some embodiments of the present invention, the ceramic layer is provided with through holes, the function of which is to connect two adjacent conductive layers.

[0082] In some embodiments of the present invention, the thickness of the ceramic layer is 10–15 μm.

[0083] The fourth aspect of the present invention provides the application of the method for preparing the conductive layer described in the first aspect of the present invention or the method for preparing the inductor described in the third aspect of the present invention in the field of manufacturing electronic products.

[0084] The beneficial effects of this invention are as follows: The method for preparing the conductive layer in this invention involves exposing a ceramic substrate coated with photosensitive conductive silver paste and then transferring it to a two-fluid developing zone for development. Compared to traditional one-fluid developing, two-fluid developing introduces gas into the liquid developer, and the interaction between the two fluids atomizes the developer A, forming extremely small developer A particles that can penetrate to the bottom of lines with small line spacing, improving the resolution of the developed lines. Furthermore, atomization helps to ensure uniform distribution of developer A on the substrate, avoiding over-development and improving the uniformity of development. Simultaneously, by adjusting the volume ratio of liquid to gas in developer A, the development and dissolution rate can be controlled more accurately; for extremely fine lines, "micro-engraving" can be performed, resulting in a wider development process range and more stable development. Attached Figure Description

[0085] Figure 1 This is a schematic diagram of the ceramic substrate coated with photosensitive conductive silver paste in Example 1.

[0086] Figure 2 This is a schematic diagram of the exposure process during the fabrication method of the inductor in Example 1.

[0087] Figure 3 This is a schematic diagram of the development process during the fabrication of the inductor in Example 1.

[0088] Figure 4 This is a schematic diagram of the structure of the conductive layer prepared in Example 1. Detailed Implementation

[0089] The specific implementation of the present invention will be further described in detail below with reference to the accompanying drawings and examples, but the implementation and protection of the present invention are not limited thereto. It should be noted that any processes not specifically described in detail below are those that can be implemented or understood by those skilled in the art by referring to the prior art. Reagents or instruments used without specified manufacturers are all conventional products that can be purchased commercially.

[0090] Example 1

[0091] This example provides a method for fabricating an inductor, with the specific steps as follows:

[0092] (1) Photosensitive ceramic paste is coated on the surface of the carrier by printing and then dried to obtain a ceramic substrate 1 with a thickness of 20μm; the size of the ceramic substrate 1 is approximately 130mm*130mm.

[0093] The carrier board is made of fiberglass board. The drying temperature is 60℃ and the drying time is 10min.

[0094] The specific composition of the photosensitive ceramic paste, by mass percentage, is as follows: 55% inorganic powder, 40% polymethyl methacrylate (PMMA) resin, 0.3% triphenylphosphine oxide initiator, 4% diethylene glycol butyl ether solvent, and 0.7% dispersant.

[0095] The inorganic powder, by mass percentage, consists of: 25% aluminum oxide, 60% silicon dioxide, 10% boron oxide, and 5% potassium oxide.

[0096] (2) Photosensitive conductive silver paste 2 is coated onto the entire upper surface of the ceramic substrate 1 prepared in step (1) by printing. A schematic diagram of the ceramic substrate 1 after coating with photosensitive conductive silver paste 2 is shown below. Figure 1 As shown, where, Figure 1 The 1 in the figure represents a ceramic substrate. Figure 12 in the figure represents photosensitive conductive silver paste, which is then dried into a conductive film. The drying temperature and time are the same as in step (1). Then, a mask 3 with the coil conductor pattern required by the design is covered on the surface of the dried conductive film. Exposure is performed under an exposure light source. After exposure, the photosensitive conductive silver paste 2 is cured. The connection diagram of the ceramic substrate 1, the photosensitive conductive silver paste 2 and the mask 3 during exposure is shown in the figure. Figure 2 As shown; after exposure, it is then placed on a horizontal conveyor roller into the two-fluid developing zone for development to form a conductive layer. The conductive layer is a conductive coil. A schematic diagram of the two-fluid developing zone during development is shown below. Figure 3 As shown, a schematic diagram of the structure of the conductive layer after development is as follows: Figure 4 As shown.

[0097] Exposure light source wavelength: 365nm, exposure time: 10s.

[0098] The specific composition of the photosensitive conductive silver paste by mass percentage is as follows: 82.4% Ag powder, 13% PMMA resin, 0.8% initiator triphenylphosphine oxide, 3% solvent diethylene glycol butyl ether, and 0.8% dispersant (i.e., polyvinyl alcohol).

[0099] The mask has a line width of 10μm and a line spacing of 15μm.

[0100] The specific steps for development in the two-fluid developing zone are as follows: After exposure, the ceramic substrate is placed on a horizontal conveyor roller and passes through the two-fluid developing zone at a speed of 0.5 m / min (i.e., through speed). The nozzles A in the two-fluid developing zone spray developing solution A for development. The length of the two-fluid developing zone is 200 mm, and there are 4 nozzles A. Developing solution A is a mixture of liquid and gas at a temperature of 25℃. The liquid volume percentage is 85%, and the gas volume percentage is 15%. The gas is compressed air, and the liquid is a 1% sodium carbonate aqueous solution (i.e., the sodium carbonate in the aqueous solution has a mass percentage of 1%). The spraying pressure of developing solution A is 0.18 MPa. Developing solution A is oscillated during spraying, with the oscillation frequency of nozzle A being 25 Hz, and the spray shape being conical. Specific parameters are shown in Table 1.

[0101] (3) A 15μm thick photosensitive ceramic paste is coated on the conductive layer by printing or other means. The formula is the same as that of the photosensitive ceramic paste in step (1). Exposure and development are performed to form a ceramic layer with through holes that connect the upper and lower layers of the conductive layer. Exposure light source wavelength: 365nm, exposure time: 5s.

[0102] The development step is as follows: the substrate is passed through a one-fluid developing zone, and the developing solution B is sprayed by nozzle B set in the one-fluid developing zone. The length of the one-fluid developing zone is 650 mm, the number of nozzles B is 8, the spray shape is conical, the speed at which the substrate passes through the one-fluid developing zone is 5 m / min, the spray pressure is 0.3 MPa, the swing frequency is 25 Hz, the temperature of the developing solution B is 25 ℃, and the developing solution B is a sodium carbonate aqueous solution with a mass concentration of 0.4%, that is, the mass percentage of sodium carbonate in the sodium carbonate aqueous solution is 0.4%.

[0103] (4) Repeat steps (2) to (3) to make ceramic and conductive layers to the specified number of layers, and then cut, fire and electroplate to obtain the inductor in this example. The firing temperature is 850℃, the firing holding time is 60min, and the firing atmosphere is air.

[0104] Examples 2-5

[0105] The only difference between the inductor fabrication methods in Examples 2-5 and Example 1 is that the substrate passes through the two-fluid development zone at different speeds during the development step, as shown in Table 1 below.

[0106] Examples 6-8

[0107] The only difference between the inductor preparation methods in Examples 6-8 and Example 1 is that the spraying pressure when spraying developer A is different in the developing step, as shown in Table 1 below.

[0108] Examples 9-11

[0109] The difference between the inductor preparation methods in Examples 9-11 and Example 1 is only that the oscillation frequency of nozzle A is different when spraying developer solution A in the developing step, as shown in Table 1 below.

[0110] Examples 12-15

[0111] The difference between the inductor preparation methods in Examples 12-15 and Example 1 lies only in the following: in the developing step, the liquid percentage in developer A is different, as shown in Table 1 below.

[0112] Examples 16-17

[0113] The difference between the inductor preparation methods in Examples 16 and 17 and those in Example 1 is only that the temperature of the developer A is different in the developing step, as shown in Table 1 below.

[0114] Examples 18-19

[0115] The difference between the inductor preparation methods in Examples 18 and 19 and those in Example 1 lies only in the mass percentage of sodium carbonate in the sodium carbonate aqueous solution during the development step, as shown in Table 1 below.

[0116] Examples 20-24

[0117] The only difference between the inductor preparation methods in Examples 20-24 and Example 1 is that the gas in developer A is compressed nitrogen in the developing step, and the volume percentage of liquid in developer A is different in Examples 20-22 and Example 24, as shown in Table 1 below.

[0118] Examples 25-26

[0119] The only difference between the inductor fabrication method in Examples 25 and 26 and Example 1 is that the substrate passes through the two-fluid development zone at different speeds during the development step, as shown in Table 1 below.

[0120] Examples 27-28

[0121] The difference between the inductor preparation method in Examples 27 and 28 and that in Example 1 is only that the spraying pressure when spraying developer A is different in the developing step, as shown in Table 1 below.

[0122] Examples 29-30

[0123] The difference between the inductor preparation method in Examples 29 and 30 and that in Example 1 is only that the oscillation frequency of nozzle A is different when spraying developer solution A in the developing step, as shown in Table 1 below.

[0124] Example 31

[0125] The difference between the inductor preparation method in Example 31 and Example 1 is that the liquid percentage in developer A is different in the developing step, as shown in Table 1 below.

[0126] Examples 32-33

[0127] The difference between the inductor preparation methods in Examples 32 and 33 and those in Example 1 is only that the temperature of the developer A is different in the developing step, as shown in Table 1 below.

[0128] Examples 34-35

[0129] The difference between the inductor preparation methods in Examples 34 and 35 and Example 1 is only that the mass percentage of sodium carbonate in the sodium carbonate aqueous solution is different in the development step, as shown in Table 1 below.

[0130] Table 1. Fabrication parameters of the inductors in Examples 1-35

[0131]

[0132]

[0133] Example 36

[0134] The difference between the inductor fabrication method in this example and that in Example 1 is that step (2) in this example involves pre-developing in a first fluid development zone and then entering a second fluid development zone for further development.

[0135] The specific steps for developing in the one-fluid developing zone are as follows: the substrate is passed through the one-fluid developing zone, and the developing solution B is sprayed from nozzle B located in the one-fluid developing zone. The length of the one-fluid developing zone is 600 mm, the number of nozzles B is 6, the spray shape is conical, the speed at which the substrate passes through the one-fluid developing zone is 2.0 m / min, the spray pressure is 0.15 MPa, the swing frequency is 25 Hz, the temperature of the developing solution B is 25 ℃, and the developing solution B is a sodium carbonate aqueous solution with a mass concentration of 0.4%, that is, the mass percentage of sodium carbonate in the sodium carbonate aqueous solution is 0.4%. The specific parameters are shown in Table 2.

[0136] The specific parameters of the two-fluid developing zone differ from those in Example 1 in that: the flow rate is 3 m / min, the spray pressure is 0.13 MPa, the swing frequency is 25 Hz, the volume percentage of liquid in developer A is 60%, the volume percentage of gas is 40%, the liquid is a sodium carbonate aqueous solution with a mass concentration of 0.4%, and the temperature of developer B is 25°C. The specific parameters are shown in Table 3.

[0137] Examples 37-39

[0138] The only difference between the inductor preparation methods in Examples 37-39 and Example 36 is that the flow rate during development in the fluid development zone is different, as shown in Table 2.

[0139] Examples 40-42

[0140] The only difference between the inductor preparation methods in Examples 40-42 and Example 37 is that the spray pressure during development in the fluid development zone is different, as shown in Table 2.

[0141] Examples 43-44

[0142] The only difference between the inductor preparation method in Examples 43 and 44 and that in Example 37 is that the oscillation frequency during development in the fluid development zone is different, as shown in Table 2.

[0143] Examples 45-47

[0144] The inductor preparation methods in Examples 45-47 differ from those in Example 37 only in that the temperature of the developer B during development in the fluid development zone is different, as shown in Table 2.

[0145] Examples 48-50

[0146] The only difference between the inductor preparation methods in Examples 48-50 and Example 37 is that the mass concentration of sodium carbonate aqueous solution in developer B is different during development in a fluid development zone, as shown in Table 2.

[0147] Examples 51-52

[0148] The only difference between the inductor preparation methods in Examples 51 and 52 and those in Example 37 is that the flow rate during development in the fluid development zone is different, as shown in Table 2.

[0149] Examples 53-54

[0150] The only difference between the inductor preparation method in Examples 53 and 54 and that in Example 37 is that the spray pressure during development in the fluid development zone is different, as shown in Table 2.

[0151] Examples 55-56

[0152] The only difference between the inductor preparation methods in Examples 55 and 56 and those in Example 37 is that the oscillation frequency during development in the fluid development zone is different, as shown in Table 2.

[0153] Examples 57-58

[0154] The only difference between the inductor preparation method in Examples 57 and 58 and that in Example 37 is that the temperature of the developer B during development in the fluid development zone is different, as shown in Table 2.

[0155] Examples 59-60

[0156] The only difference between the inductor preparation methods in Examples 59 and 60 and those in Example 37 is that the mass concentration of sodium carbonate aqueous solution in developer B is different during development in a fluid development zone, as shown in Table 2.

[0157] Comparative Example 1

[0158] The difference between the inductor fabrication method in this example and that in Example 37 is that the substrate in step (2) of this example was developed only in the first fluid development area and not in the second fluid development area, as shown in Table 2.

[0159] Table 2 shows the parameters for the development of the one-fluid development zone during the fabrication of inductors in Examples 36-60 and Comparative Example 1.

[0160]

[0161]

[0162] Table 3. Parameters for the development of the two-fluid development zone during inductor fabrication in Examples 36-60.

[0163]

[0164] Performance testing:

[0165] The line width, line spacing, line thickness, and taper of the developed lines of the inductors prepared in Examples 1-60 and Comparative Example 1 were tested respectively. The specific test methods are as follows:

[0166] Line width: Line width was measured in 9 areas on the substrate, with 3 lines measured in each area; the measuring instrument was an image measuring instrument. The average line width and line width range of all measurement points were calculated. An average line width of 20 μm was used as an example, and a line width of 20 ± 0.5 μm was considered optimal.

[0167] Line spacing: Line spacing was measured in 9 regions on the substrate, with 3 measurements taken in each region; the measuring instrument was an image measuring instrument. The average line spacing and the range of line spacing were calculated for all measurement points. Taking an average line width of 10μm as an example, a line spacing of 9±0.5μm is considered optimal.

[0168] Line thickness: Line thickness was measured in 9 regions on the substrate, with 3 lines measured in each region; the measuring instrument was a 3D laser microscope. The average line thickness and the range of line thickness at all measurement points were calculated. An average line thickness of 10 μm was used as an example; a line thickness of 10 ± 0.5 μm was considered optimal.

[0169] Developed line taper: Samples are taken from 5 regions on the substrate, with 2 lines sampled from each region; after DPA polishing and curing, the taper value of the line cross-section is measured. Taper value = substrate-side line width / non-substrate-side line width. Performance is optimal when the taper value meets the requirement of 95%-105%.

[0170] Then, the inductance, quality factor, DC resistance, and DC resistance dispersion of the inductors prepared in Examples 1 to 60 and Comparative Example 1 were tested. The specific test methods and test instruments are shown in Table 4 below.

[0171] Table 4. Test methods for inductance value, quality factor, DC resistance, and DC resistance dispersion.

[0172]

[0173] The performance data of the inductors in Examples 1 to 60 and Comparative Example 1, measured according to the above test method, are shown in Table 5 below.

[0174] Table 5 shows the performance test results of the inductors in Examples 1-60 and Comparative Example 1.

[0175]

[0176]

[0177]

[0178] As shown in Table 5, compared with Examples 25-35 and Examples 51-60, the inductors prepared in Examples 1-24 and Examples 36-50 have better performance in various aspects, satisfying the following requirements: line width within 20±0.5μm, line spacing within 9±0.5μm, line thickness within 10±0.5μm, developing line taper within 95%-105%, inductance value L within 10±0.5nH, quality factor Q within 14.7-16.13, DC resistance RDC within 1007-1341mΩ, and DC resistance dispersion within 14.6-27. The following analysis is based on specific examples:

[0179] By comparing Examples 1-2 and Example 25, it can be seen that when the substrate passes through the two-fluid developing zone at different speeds, the total developing time of the substrate will be shortened as the developing speed increases. As the total developing time gradually shortens, the rinsing effect of developer A gradually improves, the line width increases from 18.6 μm to 20 μm, the line taper increases from 92% to 96.9%, and the concentration is also improved to a certain extent. However, as the total developing time is further shortened, the rinsing effect of developer A gradually decreases. For example, in Examples 2-5 and Example 26, it can be seen that the line width becomes larger and larger. This is because a small amount of uncured paste will remain on the substrate.

[0180] By comparing Examples 2, 6, 7, 8 and Examples 27-28, it can be seen that when developing in the two-fluid developing zone, if the spray pressure increases, the line width on the substrate tends to narrow. When the spray pressure is increased from 0.1 MPa to 0.2 MPa, the line width narrows slightly and the taper decreases by about 1.5%.

[0181] Comparing Examples 2, 9, 10, 11 and Examples 29-30, it is evident that a swing speed of 20-30 Hz is optimal for development in the two-fluid developing zone. When the swing speed exceeds 30 Hz, the swing speed becomes too fast, reducing the impact force of development, resulting in slightly thicker line widths and a deterioration in dispersion. When the swing speed decreases to below 20 Hz, the development uniformity significantly decreases. Although the average values ​​of line width and line thickness do not show significant differences, the dispersion value of the finished product's DC resistance can reach over 40.

[0182] By comparing Examples 2, 12, 13, 14, 15 and Example 31, it can be seen that when developing in the two-fluid developing zone, the volume ratio of liquid in developer A should be maintained above an appropriate ratio. Under the same flow rate and spray pressure, when the liquid ratio in developer A is less than 50%, the number of effective liquid particles in developer A is significantly less, the line width gradually increases to 20.6 μm, and the taper value gradually increases to 105.1%.

[0183] By comparing Examples 12-15 and Examples 20-24, it can be seen that using other compressed gases (such as nitrogen) instead of compressed air to provide the spray power source does not show significant differences in the development effect. The differences in line width and line taper are small and have basically no impact.

[0184] Comparative studies of Examples 2, 16, 17, and 32-33 show that increasing the temperature of developer A significantly accelerates the developing process. When the temperature of developer A increases from 20°C to 40°C, the line width decreases from 20.8 μm to 19.1 μm, the line thickness decreases from 10 μm to 9.3 μm, and the taper value also decreases from 108.4% to 92.1%.

[0185] Comparative studies of Examples 2, 18, 19, and Examples 34-35 show that the concentration of sodium carbonate solution also has a significant impact on the developing process. As the mass concentration of sodium carbonate in developer A increases, the reaction rate of the developing process becomes faster, and the concentration of the developed lines changes in a "dispersion-concentration-dispersion" pattern. When the mass concentration of sodium carbonate in developer A is 0.2%, the line width is 21 μm, the taper value is 122.8%, and the dispersion coefficient is approximately 29. When the mass concentration of sodium carbonate in developer A is too high, the line width narrows to 19 μm, the taper value is 89.7%, and the dispersion coefficient is 36.

[0186] Of course, to improve the overall production efficiency of the developing process, single-fluid developing and two-fluid developing can be combined to build a new developing line. The entire developing area will include two parts: a single-fluid developing area and a two-fluid developing area, as shown in Examples 36-60. Compared with two-fluid developing alone, the adjustment of various parameters after combining single-fluid developing and two-fluid developing has a basically consistent effect on the performance of the inductor. For example, an increase in throughput speed will lead to a wider linewidth and a larger taper value. After combining single-fluid and two-fluid developing, a comparison of Examples 36-39 and Examples 51-56 shows that the optimal throughput speed is about 3-4 m / min, and the concentration of developer B is reduced from 1% in single-fluid developing to 0.4%, significantly improving the buffering stability of developer B.

[0187] The embodiments of the present invention have been described in detail above. However, the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present invention. Furthermore, the embodiments of the present invention and the features thereof can be combined with each other unless otherwise specified.

Claims

1. A method for preparing a conductive layer, characterized in that: Includes the following steps: A photosensitive conductive silver paste is coated onto a substrate, exposed, and developed to form a conductive layer on the substrate. The development process includes step S11, which involves: developing by spraying developing solution A through a nozzle A located in the two-fluid developing zone. The developer A contains gas and liquid, wherein the liquid is a solution containing at least one solute selected from alkaline inorganic salts and organic bases, and the volume percentage of liquid in the developer A is 40-99%.

2. The method for preparing the conductive layer according to claim 1, characterized in that: Step S11 has at least one of the following characteristics: (a1) The passage speed through the two-fluid developing zone is 0.3 to 4.5 m / min; (a2) The spray pressure of the developer A is 0.05 to 0.25 MPa; (a3) The temperature of the developer A is 20–40°C; (a4) The liquid contains a solute with a mass percentage of 0.2% to 2%; (a5) The gas is selected from at least one of compressed air and compressed inert gas; (a6) The length of the two-fluid developing zone is 180–220 mm; (a7) The oscillation frequency of the nozzle A is 10 to 40 Hz; (a8) The number of nozzles A is 2 to 4.

3. The method for preparing the conductive layer according to claim 1, characterized in that: The development process further includes step S12, which precedes step S11. Step S12 involves spraying developing solution B through a nozzle B located in a fluid developing zone. The developing solution B is a solution containing at least one solute selected from alkaline inorganic salts and organic bases.

4. The method for preparing the conductive layer according to claim 3, characterized in that: Step S12 has at least one of the following characteristics: (b1) The length of the fluid development zone is 600-750 mm; (b2) The number of nozzles B is 6 to 10; (b3) The oscillation frequency of the nozzle B is 10 to 40 Hz; (b4) The developer B contains 0.05 to 1% solute by mass; (b5) The passage speed through the fluid developing zone is 1 to 6 m / min; (b6) The spray pressure of the developer B is 0.05 to 0.4 MPa; (b7) The temperature of the developer B is 10 to 35°C.

5. The method for preparing the conductive layer according to claim 1, characterized in that: The conductive layer has at least one of the following characteristics: (c1) The thickness of the conductive layer is 15–20 μm; (c2) The conductive layer includes a conductive coil.

6. The method for preparing the conductive layer according to claim 1, characterized in that: The exposure step is as follows: a photomask is placed over a substrate coated with photosensitive conductive silver paste, and then exposed to a light source.

7. The method for preparing the conductive layer according to claim 6, characterized in that: The exposure has at least one of the following characteristics: (d1) The line width of the mask is 5-10 μm; (d2) The line spacing of the mask is 10-15 μm; (d3) The wavelength of the light source is 345–385 nm; (d4) The exposure time is 5 to 20 seconds.

8. An inductor, characterized in that: It includes a conductive layer prepared by the preparation method according to any one of claims 1 to 7.

9. The method for preparing the inductor according to claim 8, characterized in that: Includes the following steps: (1) The conductive layer is prepared by the preparation method according to any one of claims 1 to 7; (2) Coat the conductive layer with photosensitive ceramic paste, expose, develop, and form a ceramic layer; (3) According to the structure of the inductor, the conductive layer and the ceramic layer are prepared in sequence on the ceramic layer, and then fired and electroplated to obtain the inductor.

10. The application of the method for preparing the conductive layer according to any one of claims 1 to 7 or the method for preparing the inductor according to claim 9 in the manufacture of electronic products.

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