CN114956793A - Ceramic slurry for 3D printing ceramic electronic circuit, preparation technology thereof and mixed additive manufacturing method - Google Patents

Abstract

The invention discloses a ceramic slurry for 3D printing ceramic electronic circuits, a preparation technology and a mixed additive manufacturing method. The steps are: mixing components of the ceramic slurry with a high-speed vacuum mixer to obtain a 3D printing slurry; according to numerical control programming language codes The printer is driven to print the ceramic slurry layer by layer, and the formed ceramic blank is dried, degreasing and sintered to form a dense ceramic structure; laser equipment is used to activate the ceramic surface according to the circuit pattern, so that the ceramic surface can be laser activated metal Compounds generate electroless plating catalysts; selective metal deposition is carried out on the three-dimensional ceramic structure activated by electroless plating, and a dense metal layer is formed only in the laser-activated area, thereby fabricating circuit structures on the ceramic substrate; electronic components are installed in the corresponding positions of the circuit board substrate components, and finally obtain ceramic electronic circuit products. The invention can customize the 3D printing ceramic slurry according to the actual functional requirements of users, which is convenient and efficient.

Description

Ceramic paste for 3D printing ceramic electronic circuits and its preparation technology and hybrid additive manufacturing method

technical field

The invention relates to a ceramic slurry preparation technology and a hybrid additive manufacturing method for 3D printing ceramic electronic circuits, and belongs to the technical field of additive manufacturing.

Background technique

At present, most electronic circuit products are manufactured using printed circuit board technology (PCB), but this technology generally uses polymer or glass fiber boards as substrates. Because the polymer materials contained in the PCB board generally have low melting point, large thermal expansion coefficient, and low mechanical strength, it is difficult to use in harsh working environments, and cannot meet the requirements of military electronics, aerospace, and information systems for high temperature, humidity, and reliability. Customized demand in high-end manufacturing fields such as communications. In comparison, ceramic materials have the advantages of high temperature resistance, small thermal expansion coefficient, strong electrical insulation performance, high mechanical strength, high thermal conductivity, and high chemical stability, making them an ideal choice to replace polymers. At present, ceramic electronic circuit products mainly rely on co-fired ceramic technology (such as: LTCC, HTCC technology, etc.) for manufacturing. This technology uses ceramic powder to make a green ceramic tape and punches it. After the circuit is patterned by metal conductor paste printing, it is laminated layer by layer, and finally debonded and sintered to manufacture a multi-layer ceramic circuit. However, this technology has many processes, long production cycle and high input cost. With the advancement of science and technology, many industries have put forward higher requirements for the performance of ceramic electronic products. For example, communication engineering, aviation and aerospace engineering and other fields need to be able to quickly, economically and efficiently manufacture customized electronic circuit products with complex three-dimensional structures. Such as 5G conformal antennas, three-dimensional circuit boards, etc., to improve product performance, reduce overall weight, improve integration, and reduce product size. However, co-fired ceramic technology can only manufacture two-dimensional planar circuit boards, and at the same time, it cannot complete the customized rapid manufacturing of three-dimensional ceramic electronic devices at a low cost. Therefore, the present invention proposes a ceramic slurry preparation technology and a hybrid additive manufacturing method for 3D printing ceramic electronic circuits. The method has few steps, short production cycle and low cost, and can complete the manufacture of customized three-dimensional ceramic electronic devices.

SUMMARY OF THE INVENTION

Purpose of the invention: One of the purposes of the present invention is to provide a ceramic slurry preparation technology and a hybrid additive manufacturing method based on 3D printing ceramic electronic circuits, so as to solve the problem that conventional ceramic electronic device manufacturing methods cannot quickly customize three-dimensional electronic circuits. And its equipment is expensive, and it is not suitable for small and medium-scale customized production; the second purpose of the present invention is to provide a configuration method for 3D printing paste for ceramic electronic devices mixed with additive manufacturing methods.

Technical solution: The ceramic slurry for 3D printing ceramic electronic circuits, in parts by mass, the raw material composition is:

The glass phase is a metal oxide; the components are not zero.

The ceramic powder is one or more of aluminum oxide, aluminum nitride, barium titanate, strontium titanate, lead zirconate titanate, zirconium oxide, silicon carbide, and silicon nitride; the glass phase is oxide One or more of potassium, sodium oxide, lead oxide, silicon oxide, aluminum oxide, boron oxide, and magnesium oxide.

The laser-activatable metal compound is one or more of copper oxide, chromium oxide, copper-chromium spinel, nickel oxide, iron oxide, antimony oxide, tin oxide, titanium oxide, and tin oxide.

The binder is polyvinyl alcohol (PVA), polyvinyl butyral ester (PVB), polyvinyl chloride (PVC), polyvinylidene fluoride (PVDF), polylactic acid (PLA), polymethacrylic acid One or more of methyl esters (PMMA); the dispersant is a mixture of phosphoric acid polyester and phosphoric acid, or a mixture of 1-methoxy-2-propanol acetate and butyl acetate.

The solvent is one or more of water, ethanol, isopropanol (IPA), acetone, N,N-dimethylformamide (DMF) and tetrahydrofuran (THF).

The preparation technology of ceramic slurry for 3D printing ceramic electronic circuit includes the following steps:

(1) Put the glass phase into a crucible, heat and melt it in a muffle furnace, quickly pour it into cold water to quench the glass slag, pour the glass slag into an agate tank, and use anhydrous ethanol as a medium for ball milling, Sieve and dry to obtain glass phase powder;

(2) The components of the 3D printing ceramic slurry are put into the mixing tank according to the proportion and zirconia ball grinding beads, and the 3D printing ceramic slurry is prepared by vacuum high-speed mixing.

Based on the hybrid additive manufacturing method of ceramic slurry for 3D printing ceramic electronic circuits, the steps are:

(1) Preparation of ceramic slurry: First prepare glass phase powder, and then mix with other components of ceramic slurry by high-speed vacuum mixer to obtain ceramic slurry for 3D printing;

(2) Manufacture of ceramic blanks: 3D printing equipment is used according to the design structure, and the printer is driven to print ceramic slurry layer by layer according to the numerical control programming language code to manufacture ceramic blanks;

(3) Firing: drying, degreasing, and sintering the printed ceramic blanks at different temperatures at different temperatures to form a dense ceramic structure;

(4) Laser activation: The ceramic surface is activated by laser according to the electronic product design model to provide catalytic sites for subsequent electroless plating;

(5) Electroless plating: perform chemical plating on the three-dimensional ceramic structure activated by the laser, form a dense metal layer in the laser-activated area, and finally obtain the finished ceramic electronic device;

(6) Assembly: Install electronic components at the corresponding positions of the circuit board base.

In step (2), the material printing nozzle used by the 3D printing equipment is one of a pneumatic extrusion device, a screw extrusion device, and an inkjet printing device; the drying, degreasing, and sintering temperature in step (3) According to the material, the temperature and time are 60~100℃ for 48 hours, 300~550℃ for 2~5 hours, and 800~1800℃ for 2~8 hours; the drying and degreasing are air atmosphere, and the sintering atmosphere is air, Nitrogen, argon atmosphere.

In the step (4), all kinds of lasers with a wavelength of 200 nm to 10.6 μm used for the laser activation are used.

In the hybrid additive manufacturing method, the chemical plating process in step (5) is any one of chemical copper plating, chemical nickel plating, and chemical gold plating, and the coating is a single-material coating, or a combination of multiple chemical plating processes. Composite coating; Step (6) The electronic components are installed by manual or automatic placement machine using conductive glue or reflow soldering according to the design.

Beneficial effects:

Due to the high content of powder in the ceramic slurry, the particle size and gradation of the powder have a great influence on the molding and performance of the ceramic. As the particle size of the powder decreases, the specific surface area increases, and the viscosity of the slurry increases sharply, which is not conducive to the extrusion of the slurry in the 3D printing process. In addition, reasonable powder particle size and gradation are easy to realize the optimization of powder stacking in the sintering process, fill the voids generated by debinding, and improve the density of ceramics. To this end, the invention adopts the method of wet planetary ball milling to control the particle size and gradation of the powder. After drying, it is pulverized and sieved to obtain ultra-fine powder. At the same time, the particle size distribution of the powder is controlled to avoid powder agglomeration and agglomeration. In addition, the ceramic slurry in the present invention is prone to agglomeration and agglomeration of the powder in the organic carrier during the preparation process due to factors such as high solid content, small powder particles, high surface energy, and large agglomeration tendency. Therefore, the present invention selects a dispersant and a binder system matching the properties of the powder, and reduces the surface energy between the particles by wetting and coating the surface of the ultrafine particles, thereby playing the role of uniform and stable dispersion. In addition, in the present invention, the process method of "filtration + rolling + vacuum defoaming and stirring" can be used to further treat the agglomerates that may exist in the slurry. The specific plan is as follows: first, filter the slurry with low viscosity after ball milling, and filter out large particles by pumping into the filter; then, at a certain temperature, part of the solvent is volatilized to increase the viscosity of the slurry, and the three-roll rolling method Dispersing the components of the slurry uniformly can effectively reduce the fineness of the slurry and avoid the occurrence of agglomerates or large particles.

Since the paste has lower viscosity at high shear rate and higher viscosity at low shear rate, the paste has higher fluidity during printing for smooth printing and lower viscosity after extrusion molding Fluidity to maintain shape. At the same time, the heating base plate is used to heat the printing structure during the printing process. Since the solvent selected for the paste is easy to volatilize and has a low content, most of the solvent will be volatilized in a short time after the paste is printed to maintain the structure and shape, so as to maintain the shape of the structure. The underlying structure is kept stable in subsequent prints. Finally completed the manufacture of ceramic 3D blanks.

The proportion of the ceramic slurry in the present invention is set based on its physical and chemical properties, and achieves the effects of moderate viscosity, fast thermal curing speed during printing, fast degreasing speed, shrinkage rate and porosity after sintering. Among them, when the mass fraction of solids (ceramic powder, glass phase, laser-activatable metal compound) in the slurry is less than 60%, the slurry will show a low viscosity and cannot keep the shape after printing; the solids (ceramic powder) in the slurry , glass phase, laser-activatable metal compounds) when the mass fraction is greater than 70%, due to the higher solid content, the viscosity of the slurry is higher, which requires a larger extrusion pressure and is not conducive to printing control.

The 3D printing parameters in the present invention are determined based on a large number of experimental researches, and the advantages of fast manufacturing speed, high manufacturing yield, high manufacturing precision, and low void ratio of the printed structure are realized. Among them, the diameter and layer thickness of the extrusion needle or nozzle are determined according to the precision required for manufacturing ceramic devices. The running speed must match the extrusion pressure. When the extrusion pressure is high and the flow rate of the extrusion slurry is large, a larger needle or nozzle needs to be used. When the extrusion pressure is low and the flow rate of the printing paste is small, a lower needle or nozzle travel speed is required. The print yield increases as the needle or nozzle travel speed decreases.

In the present invention, the parameters of drying, degreasing and sintering are determined based on a large number of experimental studies. During the drying process, all the water in the ceramic blank can be discharged. During the degreasing process, the heating rate, the final temperature and the holding time are selected according to the additive content in the blank. The parameters of the sintering process are determined according to the type of ceramic and glass phase selected. If there is no drying process, the ceramic blank may crack during the degreasing process; if the degreasing heating rate is fast, the gas in the blank will be discharged too quickly, thereby reducing the density or even cracking.

The laser activation parameters in the present invention are determined based on a large number of experimental studies. When other parameters are fixed and the laser activation power is too high, the higher temperature will cause chemical changes to the catalyst activated by the laser for chemical plating, and the chemical plating cannot be completed; When the activation power is low, a sufficient amount of catalyst for electroless plating cannot be obtained, and the electroless plating cannot be completed quickly or even completed.

The invention makes a breakthrough in using 3D ceramic printing for electronic circuit manufacturing, that is, the invention prepares a ceramic slurry that can be used for ceramic 3D printing and used for ceramic electronic circuit manufacturing. The material and process of the present invention can manufacture ceramic blanks by 3D printing technology, and then perform laser-activated selective electroless plating after degreasing and sintering process to manufacture two-dimensional/three-dimensional ceramic electronic devices, which can be applied to aerospace, automobile industry, microwave Communication devices, handicraft manufacturing and many other fields. Compared with the traditional technology, the present invention can rapidly manufacture customized electronic circuit products with high precision, low cost and complex three-dimensional structure, without relying on expensive equipment and molds.

Description of drawings

Fig. 1 is the schematic flow sheet of the present invention;

Fig. 2 is the degreasing sintering curve of Example 1 in the present invention;

Fig. 3 is the variation curve of the viscosity of ceramic slurry with solid content of Example 1 in the present invention;

Fig. 4 is the basic line width of the ceramic slurry of Example 1 of the present invention under different pressures;

Fig. 5 is the thermogravimetric analysis (TGA-DSC) curve of the prime embryo structure of embodiment 1 of the present invention;

6 is a scanning electron microscope test result of the sintered ceramic section of Example 1 of the present invention;

7 is a scanning electron microscope test result after laser activation of the surface of the sintered ceramic of Example 1 of the present invention;

8 is a scanning electron microscope test result after the electroless plating on the surface of the sintered ceramic of Example 1 of the present invention;

Fig. 9 is the surface X-ray photoelectron spectroscopy (XPS) before and after laser activation of embodiment 1 of the present invention;

FIG. 10 is the energy dispersive X-ray spectroscopic analysis (EDS) of the plated metal copper of Example 1 of the present invention;

Fig. 11 is the ceramic thermal conductivity test result of Example 1 in the present invention;

12 is a photo of the ceramic and electroless plating surfaces of Example 1 of the present invention after tin planting respectively;

Fig. 13 is the manufacturing flow chart of the ceramic LED circuit board containing micro-channel water cooling and heat dissipation according to Example 6 of the present invention;

14 is an infrared thermal imaging diagram of the ceramic LED circuit board containing micro-channel water-cooled heat dissipation of Example 6 of the present invention without water-cooling;

15 is an infrared thermal imaging diagram of the ceramic LED circuit board with water cooling and heat dissipation at 20°C according to Example 6 of the present invention;

FIG. 16 is an infrared thermal imaging diagram of the ceramic LED circuit board with water cooling and heat dissipation at 5°C according to Example 6 of the present invention.

Detailed ways

The present invention will be further described in detail below with reference to the embodiments.

The raw materials and reagents used in the following examples are commercially available.

The invention provides a ceramic slurry preparation technology and a hybrid additive manufacturing method for 3D printing ceramic electronic circuits, comprising the following steps:

(1) Preparation of ceramic slurry, the main components of the ceramic slurry are mixed by a high-speed vacuum mixer to obtain a ceramic 3D printing slurry, which is characterized in that it includes the following raw materials in parts by weight:

components are not 0.

(2) Design the base model and circuit graphics of the electronic device, design the printing parameters according to the base model, and slice the base to form the numerical control programming language code;

(3) The 3D printing equipment is used to drive the printer to print the ceramic slurry layer by layer according to the numerical control programming language code to manufacture the ceramic blank;

(4) Drying, degreasing and sintering the printed ceramic blanks at different temperatures at different temperatures to form a dense ceramic structure;

(5) Use laser to activate the ceramic surface according to the electronic product design model to provide catalytic sites for subsequent electroless plating;

(6) chemically plating the three-dimensional ceramic structure after laser activation, forming a dense metal layer in the laser activation area, and finally obtaining a finished ceramic electronic device;

(7) Install electronic components at the corresponding positions of the circuit board base.

In the above-mentioned ceramic slurry preparation technology and hybrid additive manufacturing method for 3D printing ceramic electronic circuits, the ceramic slurry is a non-Newtonian fluid formed by doping a solvent, an additive, a laser-activatable metal compound, a ceramic powder and a glass phase powder. Among them, the ceramic powder and the glass phase are the materials or precursors of the final ceramic structure; the laser-activatable metal compound provides the ceramic matrix with a catalyst that can generate elemental copper in the electroless copper plating solution under the laser; the binder can be used in Prevents structural cracking during blank printing and drying; dispersants reduce the viscosity of ceramic slurries to obtain higher solids slurries.

The ceramic powder is one or more of ceramic and silicate materials such as alumina, aluminum nitride, barium titanate, strontium titanate, lead zirconate titanate, zirconia, silicon carbide, and silicon nitride. The type of ceramic powder selected is based on the final electronic device requirements.

The glass phase is one or more of metal oxide materials such as potassium oxide, sodium oxide, lead oxide, silicon oxide, aluminum oxide, boron oxide, and magnesium oxide. The type of glass phase powder selected is based on the final electronic device requirements.

The laser-activatable metal compound is copper oxide, one or more of metal oxide materials such as chromium oxide, copper-chromium spinel, nickel oxide, iron oxide, antimony oxide, tin oxide, titanium oxide, and tin antimony oxide. kind. The selected laser-activatable metal compound is determined by the type of ceramic powder selected.

The binder is polyvinyl alcohol (PVA), polyvinyl butyral (PVB), polyvinyl chloride (PVC), polyvinylidene fluoride (PVDF), polylactic acid (PLA), polymethyl methacrylate One of organic materials such as ester (PMMA). The selected binder is determined according to the actual situation.

The dispersant is a mixture of phosphoric acid polyester and phosphoric acid, or a mixture of 1-methoxy-2-propanol acetate and butyl acetate; wherein, the mass ratio of phosphoric acid polyester and phosphoric acid is 40-60:1 , the mass ratio of 1-methoxy-2-propanol acetate to butyl acetate is 8-10:1. Among them, the dispersant is preferably a mixture of phosphoric acid polyester and phosphoric acid.

The dissolution is one or more of organic solvents such as water, ethanol, isopropanol (IPA), acetone, N,N-dimethylformamide (DMF), tetrahydrofuran (THF) and the like. The selected solvent depends on the type of binder.

The preparation method of the ceramic slurry in the present invention is as follows: the glass phase is put into a crucible according to the proportion of components, then heated and melted in a muffle furnace, quickly poured into cold water and water to quench the glass slag, and poured into an agate tank Use absolute ethanol as the medium for ball milling for 4 hours, at a speed of 300-500 rpm, sieve through a 200-mesh sieve, and dry to obtain glass phase powder; then pour the ceramic powder, glass phase powder and laser-activatable metal compound into the agate jar again Use absolute ethanol as the medium for ball milling for 4 hours, the rotating speed is 300-500 rpm, sieve through a 200-mesh sieve, and dry the powder. The components of the 3D printing ceramic slurry were put into the mixing tank according to the proportions and zirconia ball grinding beads, and were mixed in a vacuum high-speed mixer at a speed of 1000 rpm and a pressure of 1 kPa for 30 minutes to obtain a 3D printing ceramic slurry.

Due to the high content of powder in the ceramic slurry, the particle size and gradation of the powder have a great influence on the molding and performance of the ceramic. As the particle size of the powder decreases, the specific surface area increases, and the viscosity of the slurry increases sharply, which is not conducive to the extrusion of the slurry in the 3D printing process. In addition, reasonable powder particle size and gradation are easy to realize the optimization of powder stacking in the sintering process, fill the voids generated by debinding, and improve the density of ceramics. To this end, the invention adopts the method of wet planetary ball milling to control the particle size and gradation of the powder. After drying, it is pulverized and sieved to obtain ultra-fine powder. At the same time, the particle size distribution of the powder is controlled to avoid powder agglomeration and agglomeration. In addition, the ceramic slurry in the present invention is prone to agglomeration and agglomeration of the powder in the organic carrier during the preparation process due to factors such as high solid content, small powder particles, high surface energy, and large agglomeration tendency. Therefore, the present invention selects a dispersant and a binder system matching the properties of the powder, and reduces the surface energy between the particles by wetting and coating the surface of the ultrafine particles, thereby playing the role of uniform and stable dispersion. In addition, in the present invention, the process method of "filtration + rolling + vacuum defoaming and stirring" can be used to further treat the agglomerates that may exist in the slurry. The specific plan is as follows: first, filter the slurry with low viscosity after ball milling, and filter out large particles by pumping into the filter; then, at a certain temperature, part of the solvent is volatilized to increase the viscosity of the slurry, and the three-roll rolling method Dispersing the components of the slurry uniformly can effectively reduce the fineness of the slurry and avoid the occurrence of agglomerates or large particles.

According to the invention, parameters such as CAD model, electronic device precision requirements, slurry properties and other parameters are set along with 3D printing parameters, and then the digital model is sliced to form numerical control programming language codes. The 3D printing parameters are usually: extrusion needle or nozzle diameter of 25-800μm, travel speed of 100-1000mm/s, extrusion pressure of 50-500kPa, layer thickness of 25-800μm, and printing platform temperature of 40-100℃.

During the 3D printing process of the present invention according to the above numerical control programming language code, the extrusion unit of the 3D printing equipment can be one of a pneumatic extrusion device, a screw extrusion device, and an inkjet printing device. Since the paste has lower viscosity at high shear rate and higher viscosity at low shear rate, the paste has higher fluidity during printing for smooth printing and lower viscosity after extrusion molding Fluidity to maintain shape. At the same time, the heating base plate is used to heat the printing structure during the printing process. Since the solvent selected for the paste is easy to volatilize and has a low content, most of the solvent will be volatilized in a short time after the paste is printed to maintain the structure and shape, so as to maintain the shape of the structure. The underlying structure is kept stable in subsequent prints. Finally completed the manufacture of ceramic 3D blanks.

According to the invention, the printed ceramic blanks are dried, degreasing and sintered at different temperatures and atmospheres according to their different components, so as to form a dense ceramic structure. The drying temperature is 60-100°C for 48 hours, the degreasing temperature is 300-550°C for 2-5 hours, and the sintering temperature is 800-1800°C for 2-8 hours. Among them, the drying and degreasing are air atmosphere, and the sintering atmosphere needs to choose air, nitrogen and argon atmosphere according to different materials.

The laser activation of the present invention adopts a laser with a wavelength of 350-1064 nm. The laser activation parameters are determined according to the type of ceramic substrate. The working parameters of laser activation are: power 0.5~20W, scanning speed 200~2000mm/s, frequency 20~30kHz, air or nitrogen atmosphere.

The plating solution in the electroless plating process of the present invention is an electroless copper plating solution, an electroless gold plating, and the like. Each 1L of electroless copper plating solution is composed of 8-25g of copper sulfate pentahydrate, 5-15g of glyoxylic acid, 30-100g of ETDA·2Na and 100-200mg of PEG-1000. The working temperature is 50~70℃, the pH value is 11~13, the soaking time is more than 30 minutes, and the ionized water is used for cleaning after soaking. Then the surface can be electroless gold-plated, wherein each 1L of electroless gold plating solution consists of 2-3g sodium gold sulfite, 2g thiourea, 15g-20g sodium sulfite, 10-15g sodium thiosulfate, 10-12g/L The temperature of the chemical gold plating solution is 60-75° C., the pH value is 7-8, the soaking time is 3-10 minutes, and the soaking is completed with ionized water for cleaning.

After the circuit substrate is manufactured, the electronic components can be installed by manual or automatic placement machine using conductive glue or reflow soldering method according to the design.

Example 1:

The ceramic slurry in this embodiment includes the following raw materials in parts by weight:

In the present embodiment, the technological process is as follows:

(1) Put the glass phase into a crucible and then heat it in a muffle furnace to melt it, quickly pour it into cold water and water to quench the glass slag, pour it into an agate tank and use absolute ethanol as a medium for ball milling 4 hours, rotating speed 500 r/min, sieving through a 200-mesh sieve, and drying to obtain glass phase powder;

(2) The components of the 3D printing ceramic slurry are put into the mixing tank according to the proportion and zirconia ball grinding beads, and the 3D printing ceramic slurry is prepared by vacuum high-speed mixing.

(3) Pneumatic extrusion 3D printing equipment is used to print the ceramic blank according to the design structure. The printing parameters are extrusion needle diameter 300μm, extrusion needle speed 300mm/s, extrusion pressure 50kPa, layer thickness 300μm, printing Platform temperature 60℃;

(4) Drying, degreasing and sintering the printed ceramic blanks in an air atmosphere. The drying temperature is 80°C for 48 hours; the degreasing process is divided into two stages, the temperature is 200°C and 500°C, the holding time is 30 minutes and 40 minutes, and the heating rate is 3°C/min and 1.8°C/min; The sintering temperature is 850°C, the holding time is 2 hours, and the heating rate is 8°C/min. The sintering curve is shown in Figure 2;

(5) 1064nm infrared laser is used to laser activate the ceramic surface to provide catalytic sites for subsequent electroless plating. The working parameters of laser activation are: power 3W, scanning speed 1000mm/s, frequency 20kHz, air atmosphere.

(6) Electroless copper plating is performed on the ceramic structure after laser activation. Each 1L electroless copper plating solution is composed of 10g of copper sulfate pentahydrate, 10g of glyoxylic acid, 60g of ETDA·2Na and 100mg of PEG-1000. , the working temperature of the electroless copper plating solution is 60° C., the pH value is 12, the soaking time is 2 hours, and after soaking, it is washed with ionized water.

(7) Manually install electronic components, and use conductive silver glue to complete the connection between the electronic components and the ceramic substrate.

The material selected in Example 1 was tested with a rotational viscometer, as shown in Figure 3, the slurry had non-Newtonian fluid properties, and the viscosity decreased with the increase of the shear rate. And the viscosity of this material is moderate, the slurry has high fluidity in the extrusion printing process for smooth printing, and low fluidity after extrusion to maintain the shape.

The material selected in Example 1 was printed with a 300 μm extrusion needle. When the needle traveled at a speed of 300 mm/s, the variation of the extrusion wire width with extrusion pressure was shown in Figure 4. When the extrusion pressure is 35kPa ~ 55kPa, the extruded wire width is stable, so the extrusion pressure of 50kPa is selected to manufacture a relatively dense ceramic blank structure.

The results of thermogravimetric analysis (TGA-DSC) of the preform printed with the material selected in Example 1 are shown in Figure 5. The results show that the ceramic preform can discharge all additives in the preform during the degreasing and sintering process. , and remained weight stable after 500°C.

Fig. 6 shows the result of scanning electron microscope test of the cross section of the sintered ceramic in Example 1. The result shows that the ceramic powder and the laser-activatable metal compound are completely and uniformly dispersed in the glass phase.

The results of scanning electron microscopy after laser activation of the surface of the sintered ceramic in Example 1 are shown in Figure 7, and the results show that the surface of the ceramic is rough.

The scanning electron microscope test results of the electroless plating on the surface of the sintered ceramic in Example 1 are shown in FIG. 8 . The results show that a dense copper layer has been deposited on the ceramic surface.

X-ray photoelectron spectroscopy (XPS) was performed on the surfaces before and after laser activation in Example 1. The results are shown in Figure 9. The results show that the laser-activatable metal compound is converted from bivalent copper to monovalent copper after laser activation.

Energy dispersive X-ray spectroscopy (EDS) was performed on the metal copper plated in Example 1. The results are shown in Figure 10. The results show that the copper content in the copper layer is greater than 94%.

The thermal conductivity test result of the sintered material in Example 1 is shown in Figure 11, and the result shows that the thermal conductivity of the ceramic is about 3W/K·m.

Figure 12 shows the photo results of the ceramic and electroless plating surfaces in Example 1 after planting tin respectively. The results show that the ceramic surface is not wetted with solder, and the copper layer surface is wetted with solder, which is conducive to the installation of electronic components.

Example 2:

The ceramic slurry in this embodiment includes the following raw materials in parts by weight:

In the present embodiment, the technological process is as follows:

(1) The components of the 3D printing ceramic slurry are put into the mixing tank according to the proportion and zirconia ball grinding beads, and the 3D printing ceramic slurry is prepared by vacuum high-speed mixing.

(2) Using inkjet printing equipment to print the ceramic blank according to the design structure, the printing parameters are the nozzle diameter of 150μm, the travel speed of 600mm/s, the pressure of 100kPa, the layer thickness of 150μm, and the printing platform temperature of 40℃;

(3) Drying, degreasing and sintering the printed ceramic blanks in an air atmosphere. The drying temperature is 50°C for 10 hours; the degreasing process is divided into two stages, the temperature is 200°C and 500°C, the holding time is 30 minutes and 40 minutes, and the heating rate is 3°C/min and 1.8°C/min; The sintering temperature is 1200°C, the holding time is 2 hours, and the heating rate is 5°C/min;

(4) 405 UV laser was used to activate the ceramic surface by laser. The working parameters of laser activation are: power 2W, scanning speed 400mm/s, frequency 20kHz, air atmosphere.

(5) Electroless copper plating was performed on the laser-activated ceramic structure, in which 12g of copper sulfate pentahydrate, 8g of glyoxylic acid, 80g of ETDA·2Na and 200mg of PEG-1000 were mixed in each 1L of electroless copper plating solution. The working temperature of the electroless copper plating solution is 60° C., the pH value is 12, the soaking time is 2 hours, and after soaking, the solution is washed with ionized water.

(6) The electronic components are fixed by reflow soldering after installing the electronic components by the placement machine.

Example 3:

The ceramic slurry in this embodiment includes the following raw materials in parts by weight:

In the present embodiment, the technological process is as follows:

(1) The components of the 3D printing ceramic slurry are put into the mixing tank according to the proportion and zirconia ball grinding beads, and the 3D printing ceramic slurry is prepared by vacuum high-speed mixing.

(2) Using screw 3D printing equipment, the ceramic blank is printed according to the design structure. The printing parameters are the extrusion needle diameter of 300 μm, the travel speed of 300 mm/s, the layer thickness of 300 μm, and the printing platform temperature of 60 °C.

(3) Drying and degreasing the printed ceramic blanks in an air atmosphere, and sintering in a nitrogen atmosphere. The drying temperature is 50°C for 10 hours; the degreasing process is divided into two stages, the temperature is 200°C and 500°C, the holding time is 30 minutes and 40 minutes, and the heating rate is 3°C/min and 1.8°C/min; The sintering temperature was 1800°C, the holding time was 2 hours, and the temperature increase rate was 5°C/min.

(4) 1064nm infrared laser was used to activate the ceramic surface by laser. The working parameters of laser activation are: power 15W, scanning speed 400mm/s, frequency 20kHz, nitrogen atmosphere. In this embodiment, the sintered alumina material can be activated by high-temperature lasers in a protective atmosphere to generate elemental aluminum without additionally adding laserable oxides.

(5) Electroless copper plating was performed on the laser-activated ceramic structure, in which 12g of copper sulfate pentahydrate, 8g of glyoxylic acid, 80g of ETDA·2Na and 200mg of PEG-1000 were mixed in each 1L of electroless copper plating solution. The working temperature of the electroless copper plating solution is 60° C., the pH value is 12, the soaking time is 2 hours, and after soaking, the solution is washed with ionized water.

(6) Electroless gold plating is performed on the ceramic structure after electroless copper plating, wherein each 1L of electroless gold plating solution consists of 2g of sodium gold sulfite, 2g of thiourea, 20g of sodium sulfite, 15g of sodium thiosulfate, 10g/L of Borax is mixed, the temperature of the chemical gold plating solution is 65° C., the pH value is 7.5, the soaking time is 5 minutes, and after soaking, the solution is washed with ionized water.

(7) The electronic components are fixed by reflow soldering after installing the electronic components by the placement machine.

Example 4:

The ceramic slurry in this embodiment includes the following raw materials in parts by weight:

In the present embodiment, the technological process is as follows:

(1) The components of the 3D printing ceramic slurry are put into the mixing tank according to the proportion and zirconia ball grinding beads, and the 3D printing ceramic slurry is prepared by vacuum high-speed mixing.

(2) Using screw 3D printing equipment, the ceramic blank is printed according to the design structure. The printing parameters are the extrusion needle diameter of 300 μm, the travel speed of 300 mm/s, the layer thickness of 300 μm, and the printing platform temperature of 60 °C.

(3) Drying and degreasing the printed ceramic blanks in an air atmosphere, and sintering in a nitrogen atmosphere. The drying temperature is 50°C for 10 hours; the degreasing process is divided into two stages, the temperature is 200°C and 500°C, the holding time is 30 minutes and 40 minutes, and the heating rate is 3°C/min and 1.8°C/min; The sintering temperature was 1800°C, the holding time was 2 hours, and the temperature increase rate was 5°C/min.

(4) 1064nm infrared laser was used to activate the ceramic surface by laser. The working parameters of laser activation are: power 15W, scanning speed 400mm/s, frequency 20kHz, nitrogen atmosphere. In this embodiment, the sintered alumina material can be activated by high-temperature lasers in a protective atmosphere to generate elemental aluminum without additionally adding laserable oxides.

(5) Electroless copper plating was performed on the laser-activated ceramic structure, in which 12g of copper sulfate pentahydrate, 8g of glyoxylic acid, 80g of ETDA·2Na and 200mg of PEG-1000 were mixed in each 1L of electroless copper plating solution. The working temperature of the electroless copper plating solution is 60° C., the pH value is 12, the soaking time is 2 hours, and after soaking, the solution is washed with ionized water.

(6) Electroless gold plating is performed on the ceramic structure after electroless copper plating, wherein each 1L of electroless gold plating solution consists of 2g of sodium gold sulfite, 2g of thiourea, 20g of sodium sulfite, 15g of sodium thiosulfate, 10g/L of Borax is mixed, the temperature of the chemical gold plating solution is 65° C., the pH value is 7.5, the soaking time is 5 minutes, and after soaking, the solution is washed with ionized water.

(7) The electronic components are fixed by reflow soldering after installing the electronic components by the placement machine.

Example 5:

The ceramic slurry in this embodiment includes the following raw materials in parts by weight:

In the present embodiment, the technological process is as follows:

(1) Put the glass phase into a crucible and then heat it in a muffle furnace to melt it, quickly pour it into cold water and water to quench the glass slag, pour it into an agate tank and use absolute ethanol as a medium for ball milling 4 hours, rotating speed 500 r/min, sieving through a 200-mesh sieve, and drying to obtain glass phase powder;

(2) The components of the 3D printing ceramic slurry are put into the mixing tank according to the proportion and zirconia ball grinding beads, and the 3D printing ceramic slurry is prepared by vacuum high-speed mixing.

(3) Pneumatic extrusion 3D printing equipment is used to print the ceramic blank according to the design structure. The printing parameters are the extrusion needle diameter of 100 μm, the extrusion needle travel speed of 300 mm/s, the extrusion pressure of 60 kPa, and the layer thickness of 100 μm. Platform temperature 60℃;

(4) Drying, degreasing and sintering the printed ceramic blanks in an air atmosphere. The drying temperature is 80°C for 48 hours; the degreasing process is divided into two stages, the temperature is 200°C and 500°C, the holding time is 30 minutes and 40 minutes, and the heating rate is 3°C/min and 1.8°C/min; The sintering temperature is 850°C, the holding time is 2 hours, and the heating rate is 8°C/min;

(5) 1064nm infrared laser is used to laser activate the ceramic surface to provide catalytic sites for subsequent electroless plating. The working parameters of laser activation are: power 4W, scanning speed 1250mm/s, frequency 20kHz, air atmosphere.

(6) Electroless copper plating is performed on the ceramic structure after laser activation. Each 1L electroless copper plating solution is composed of 10g of copper sulfate pentahydrate, 10g of glyoxylic acid, 60g of ETDA·2Na and 100mg of PEG-1000. , the working temperature of the chemical copper plating solution is 60° C., the pH value is 12, the soaking time is 2 hours, and after soaking, it is washed with ionized water.

(7) Manually install the electronic components, and use conductive silver glue to complete the connection between the electronic components and the ceramic substrate.

Example 6:

The ceramic slurry in this embodiment includes the following raw materials in parts by weight:

In the present embodiment, the technological process is as follows:

(1) The components of the 3D printing ceramic slurry are put into the mixing tank according to the proportion and zirconia ball grinding beads, and the 3D printing ceramic slurry is prepared by vacuum high-speed mixing.

(2) Using screw 3D printing equipment, the ceramic blank is printed according to the design structure. The printing parameters are the extrusion needle diameter of 300 μm, the travel speed of 300 mm/s, the layer thickness of 300 μm, and the printing platform temperature of 60 °C.

(3) Drying, degreasing and sintering the printed ceramic blanks in an air atmosphere. The drying temperature is 50°C for 10 hours; the degreasing process is divided into two stages, the temperature is 200°C and 500°C, the holding time is 30 minutes and 40 minutes, and the heating rate is 3°C/min and 1.8°C/min; The sintering temperature was 1200°C, the holding time was 2 hours, and the temperature increase rate was 5°C/min.

(4) 1064nm infrared laser was used to activate the ceramic surface by laser. The working parameters of laser activation are: power 15W, scanning speed 400mm/s, frequency 20kHz, air atmosphere.

(5) Electroless copper plating is carried out on the ceramic structure after laser activation, and each 1 L of electroless copper plating solution is mixed with 12g of copper sulfate pentahydrate, 8g of glyoxylic acid, 80g of ETDA·2Na and 200mg of PEG-1000. The working temperature of the electroless copper plating solution is 60° C., the pH value is 12, the soaking time is 2 hours, and after soaking, the solution is washed with ionized water.

(6) Electroless gold plating is performed on the ceramic structure after electroless copper plating, wherein each 1L of electroless gold plating solution consists of 2g of sodium gold sulfite, 2g of thiourea, 20g of sodium sulfite, 15g of sodium thiosulfate, 10g/L of Borax is mixed, the temperature of the chemical gold plating solution is 65° C., the pH value is 7.5, the soaking time is 5 minutes, and after soaking, the solution is washed with ionized water.

(7) The electronic components are fixed by reflow soldering after installing the electronic components by the placement machine.

Example 7:

This embodiment provides an application example 1 of the present invention.

Example 1 was used to manufacture a ceramic LED circuit board containing micro-channels for water cooling and heat dissipation. The process flow diagram results are shown in Figure 13. Under normal operation of LEDs with a power of 2W, the infrared thermal imaging of the ceramic circuit board is shown in Figures 14 to 16 under the conditions of no water cooling, 20 °C water cooling and 5 °C water cooling, respectively.

Claims (10)

1. The ceramic slurry for 3D printing ceramic electronic circuits is characterized in that, in parts by mass, the raw material is composed of:

The glass phase is a metal oxide; the components are not zero. 2. The ceramic slurry for 3D printing ceramic electronic circuits according to claim 1, wherein the ceramic powder is aluminum oxide, aluminum nitride, barium titanate, strontium titanate, lead zirconate titanate, oxide One or more of zirconium, silicon carbide, and silicon nitride; the glass phase is one or more of potassium oxide, sodium oxide, lead oxide, silicon oxide, aluminum oxide, boron oxide, and magnesium oxide. 3. The ceramic slurry for 3D printing ceramic electronic circuits according to claim 1, wherein the laser-activatable metal compound is copper oxide, chromium oxide, copper-chromium spinel, nickel oxide, iron oxide , one or more of antimony oxide, tin oxide, titanium oxide, and tin oxide. 4. The ceramic slurry for 3D printing ceramic electronic circuits according to claim 1, wherein the binder is polyvinyl alcohol (PVA), polyvinyl butyral (PVB), polychlorinated One or more of ethylene (PVC), polyvinylidene fluoride (PVDF), polylactic acid (PLA), polymethyl methacrylate (PMMA); the dispersant is a mixture of phosphoric acid polyester and phosphoric acid, or a mixture of 1-methoxy-2-propanol acetate and butyl acetate. 5. The ceramic slurry for 3D printing ceramic electronic circuits according to claim 1, wherein the organic solvent is water, ethanol, isopropyl alcohol (IPA), acetone, N,N-dimethylformaldehyde One or more of amide (DMF), tetrahydrofuran (THF). 6. The preparation technology of ceramic slurry for 3D printing ceramic electronic circuits according to any one of claims 1 to 5, characterized in that it comprises the following steps: (1) Put the glass phase into a crucible, heat and melt it in a muffle furnace, quickly pour in cold water and water to quench the glass slag, pour the glass slag into an agate tank and use anhydrous ethanol as a medium for ball milling , sieved and dried to obtain glass phase powder; (2) The components of the 3D printing ceramic slurry are put into the mixing tank according to the proportion and zirconia ball grinding beads, and the 3D printing ceramic slurry is prepared by vacuum high-speed mixing. 7. The hybrid additive manufacturing method of ceramic slurry for 3D printing ceramic electronic circuits based on any one of claims 1 to 5, wherein the steps are: (1) Preparation of ceramic slurry: First prepare glass phase powder, and then mix with other components of ceramic slurry by high-speed vacuum mixer to obtain ceramic slurry for 3D printing; (2) Manufacture of ceramic blanks: 3D printing equipment is used according to the design structure, and the printer is driven to print ceramic slurry layer by layer according to the numerical control programming language code to manufacture ceramic blanks; (3) Firing: drying, degreasing, and sintering the printed ceramic blanks at different temperatures at different temperatures to form a dense ceramic structure; (4) Laser activation: The ceramic surface is activated by laser according to the electronic product design model to provide catalytic sites for subsequent electroless plating; (5) Electroless plating: perform chemical plating on the three-dimensional ceramic structure activated by the laser, form a dense metal layer in the laser-activated area, and finally obtain the finished ceramic electronic device; (6) Assembly: Install electronic components at the corresponding positions of the circuit board base. 8. The hybrid additive manufacturing method according to any one of claims 1 to 5, wherein in step (2), the material printing nozzle used by the 3D printing equipment is a pneumatic extrusion device, a screw extrusion One of a device and an inkjet printing device; the drying, degreasing and sintering temperatures in step (3) are respectively 60-100°C for 48 hours, 300-550°C for 2-5 hours, and 800- 1800 ℃ for 2 to 8 hours; the drying and degreasing are air atmosphere, and the sintering atmosphere is air, nitrogen and argon atmosphere according to different materials. 9 . The hybrid additive manufacturing method according to claim 1 , wherein the laser activation used in step (4) uses all types of lasers with wavelengths ranging from 200 nm to 10.6 μm. 10 . 10. The hybrid additive manufacturing method according to any one of claims 1 to 5, wherein the chemical plating process in step (5) is any one of chemical copper plating, chemical nickel plating, and chemical gold plating, The plating layer is a single-material plating layer, or a composite plating layer formed by a combination of multiple chemical plating processes; the electronic components in step (6) are installed manually or automatically using conductive glue or reflow soldering according to the design.

Images