阅读说明：本技术 一种单层电容器及其制备方法 (Single-layer capacitor and preparation method thereof ) 是由 黎兆早 余恺为 吴明洋 于 2021-09-02 设计创作，主要内容包括：本发明公开了一种单层电容器及其制备方法,包括：所述单层电容器包括陶瓷介电层和金属保护层；所述陶瓷介电层边缘延伸至金属保护层外,外延部分形成支撑体；所述陶瓷介电层上表面和下表面分别设置上电极和下电极,两者配合形成沟道结构；所述沟道结构与金属保护层中间设有电镀铜层。有益效果：通过3D打印,形成沟道结构的陶瓷介电层,实现了同尺寸下电极面积的增加和陶瓷介质厚度的降低,提升高10-100倍电容容量,增加介电常数；并通过间接曝光-逐层打印技术,提升了陶瓷晶粒的分布均匀性,实现细晶状态和晶界层的缩量,进一步增加了介电常数。(The invention discloses a single-layer capacitor and a preparation method thereof, wherein the preparation method comprises the following steps: the single-layer capacitor comprises a ceramic dielectric layer and a metal protective layer; the edge of the ceramic dielectric layer extends out of the metal protective layer, and the epitaxial part forms a support body; the upper surface and the lower surface of the ceramic dielectric layer are respectively provided with an upper electrode and a lower electrode which are matched to form a channel structure; and an electroplated copper layer is arranged between the channel structure and the metal protection layer. Has the advantages that: through 3D printing, a ceramic dielectric layer with a channel structure is formed, the increase of the area of the electrode and the reduction of the thickness of the ceramic dielectric in the same size are realized, the capacitance capacity is improved by 10-100 times, and the dielectric constant is increased; and through an indirect exposure-layer-by-layer printing technology, the distribution uniformity of ceramic grains is improved, the fine grain state and the shrinkage of a grain boundary layer are realized, and the dielectric constant is further increased.)

1. A single layer capacitor, characterized by: the single-layer capacitor comprises a ceramic dielectric layer (1) and a metal protection layer (4); the edge of the ceramic dielectric layer (1) extends out of the metal protective layer (4), and the epitaxial part forms a support body (5); an upper electrode (3-1) and a lower electrode (3-2) are respectively arranged on the upper surface and the lower surface of the ceramic dielectric layer (5), and are matched to form a channel structure; and an electroplated copper layer (2) is arranged between the channel structure and the metal protection layer (4).

2. A single layer capacitor as claimed in claim 1, wherein: the side surface of the channel structure forms an array type trapezoid cross section, and the angle range of a bottom angle (A) of the trapezoid is 65-85 ℃.

3. A single layer capacitor as claimed in claim 1, wherein: the channel structures are arranged in a plurality of numbers, and adjacent channel structures are arranged in parallel and are separated by a space (6).

4. A single layer capacitor as claimed in claim 1, wherein: the thickness of the ceramic dielectric layer (1) is 30-60 mu m; the thickness of the support body (5) is 120-240 μm; the thickness of the electrode is 1-2 μm; the material of the electrode is sequentially TiW/Ni/Au from inside to outside; the metal protection layer (4) is made of Ni/Au sequentially from inside to outside.

5. A method for preparing a single layer capacitor is characterized in that: the method comprises the following steps:

s1: placing the ceramic slurry in a DLP photocuring 3D printer, and printing by adopting an interval exposure-layering printing technology to obtain a ceramic blank;

s2: carrying out high-temperature degreasing on the ceramic blank; isostatic pressing, filling sintering aid, degreasing again and semiconductorizing; spraying an oxidant, and carrying out overall oxidation to obtain a ceramic dielectric layer (1) and a support body (5);

s3: sequentially sputtering TiW, Ni and Au on the upper surface and the lower surface of the ceramic dielectric layer (1) respectively to obtain an upper electrode (3-1) and a lower electrode (3-2); filling channels on the surfaces of the upper electrode (3-1) and the lower electrode (3-2) by using an electroplating copper solution respectively to form an electroplating copper layer (2); sequentially electroplating Ni and Au on the surface and the periphery of the electroplated copper layer (2) to serve as a metal protection layer (4), wherein the support body (5) is positioned on the outer side of the metal protection layer (4); a single layer ceramic capacitor was obtained.

6. The method of claim 5, wherein: in step S1, the thickness of each layer of the layered printing is 2 to 10 μm, the exposure light source is a soft start light source or a pulse light source, the exposure time is 5 seconds each time, and the interval time is 1 second.

7. The method of claim 5, wherein: in the step S2, the temperature of high-temperature degreasing is 600-800 ℃, and the degreasing time is 2 hours; the sintering aid is a mixture of 5-20 nm of silicon dioxide and titanium dioxide; in the process of semiconduction: the atmosphere is a reducing atmosphere, the temperature is 1380-1480 ℃, and the time is 1.5-3 hours; in the oxidation process: the atmosphere is air, the temperature is 1130-1280 ℃, and the time is 1-2 hours.

8. The method of claim 5, wherein: in step S2, the coating thickness of the oxidant is 5-10 μm; the slurry of the oxidizing agent comprises the following components: 35% by weight of Bi₂O₃、25％CuO、10％B₂O₃、25％Li₂O₃、5％Al₂O₃。

9. The method of claim 5, wherein: in step S1, in the ceramic slurry, the solid phase content is 45-50 vol%, the particle size of the ceramic particles is 300-450 nm, and the difference between the particle size of the ceramic particles and the wavelength of an exposure light source is 0-5 nm; the refractive index of the solvent is 1.4-1.5.

10. The method of claim 9, wherein: the raw materials of the ceramic slurry comprise the following components: 45-50 parts of ceramic particles, 47-50 parts of solvent, 1-2 parts of oxide, 1-3 parts of polyethyleneimine-linolenic acid compound and 0.2-1 part of initiator by weight.

Technical Field

The invention relates to the technical field of capacitors, in particular to a single-layer capacitor and a preparation method thereof.

Background

With the recent development of energy storage capacitors and other related devices mainly toward light weight, miniaturization, high insulation and high energy storage density, energy storage dielectrics are required to have higher dielectric constant, lower dielectric loss and stronger voltage resistance.

Single layer capacitors, especially grain boundary layer capacitors, are popular because of their excellent performance at high frequencies of operation. The grain boundary layer capacitor has higher dielectric constant than common ceramic capacitor, and the apparent dielectric constant E of the capacitor formed by one-time sintering_appCan reach more than 4 ten thousand. However, because the preparation process of the grain boundary layer needs to be carried out in a semiconductorization and oxidation process, the preparation method is not suitable for preparing a multilayer ceramic capacitor, and further the improvement of the capacitance of the grain boundary layer capacitor is limited.

On the other hand, the size of the current single-layer capacitor cannot be reduced due to mechanical preparation limit and device transportation limit, and the planar symmetrical electrode cannot be designed to increase the area under the trend of volume miniaturization and the traditional casting and extrusion process. Therefore, more designs are finished from the material formula and the preparation process conditions, and the amplification effect is not obvious enough.

In the prior art, partial electrodes are embedded in a laminated manner by using interposed ceramic layers, so that the capacitance of a single-layer capacitor is expected to be increased without substantially increasing the size of the total thickness, but the method is complicated in manufacturing steps and too low in efficiency; or via holes through one or more ceramic dielectric layers to provide electrical connection of one or more internal electrodes, but this approach can affect manufacturing efficiency and capacitor performance at high frequencies.

Therefore, it is important to solve the above problems and to increase the capacitance to manufacture a single layer capacitor.

Disclosure of Invention

The invention aims to provide a single-layer capacitor and a preparation method thereof, which solve the problems of small electrode area and low capacitance of the single-layer capacitor, improve the grain boundary layer forming quality of the grain boundary layer capacitor and further improve the device performance.

A single layer capacitor, characterized by: the single-layer capacitor comprises a ceramic dielectric layer and a metal protective layer; the edge of the ceramic dielectric layer extends out of the metal protective layer, and the epitaxial part forms a support body; the upper surface and the lower surface of the ceramic dielectric layer are respectively provided with an upper electrode and a lower electrode which are matched to form a channel structure; and an electroplated copper layer is arranged between the channel structure and the metal protection layer.

Preferably, the side surface of the channel structure forms an array type trapezoid cross section, and the angle range of the bottom angle of the trapezoid is 65-85 ℃. Wherein, the bottom angle is the angle of the long side of the trapezoid.

Preferably, the channel structures are arranged in a plurality of numbers, and adjacent channel structures are arranged in parallel and are separated by intervals.

Preferably, the thickness of the ceramic dielectric layer is 30-60 μm; the thickness of the support body is 120-240 mu m; the thickness of the electrode is 1-2 μm; the material of the electrode is sequentially TiW/Ni/Au from inside to outside; the material of the metal protection layer is sequentially set to be Ni/Au from inside to outside. Preferably, the preparation method of the single-layer capacitor comprises the following steps:

s1: placing the ceramic slurry in a DLP photocuring 3D printer, and printing by adopting an interval exposure-layering printing technology to obtain a ceramic blank;

s2: carrying out high-temperature degreasing on the ceramic blank; isostatic pressing, filling sintering aid, degreasing again and semiconductorizing; spraying an oxidant, and carrying out overall oxidation to obtain a ceramic dielectric layer and a support body;

s3: sequentially sputtering TiW, Ni and Au on the upper surface and the lower surface of the ceramic dielectric layer respectively to obtain an upper electrode and a lower electrode; filling channels on the surfaces of the upper electrode and the lower electrode by using an electroplating copper solution respectively to form an electroplating copper layer; sequentially electroplating Ni and Au on the surface and the periphery of the electroplated copper layer to serve as a metal protective layer, wherein the support body is positioned on the outer side of the metal protective layer; a single layer ceramic capacitor was obtained.

Preferably, in step S1, the thickness of each layer of the layered printing is 2 to 10 μm, the exposure light source is a soft start light source or a pulse light source, the exposure time is 5 seconds each time, and the interval time is 1 second.

Preferably, in step S2, the temperature of the high-temperature degreasing is 600-800 ℃, and the degreasing time is 2 hours; the sintering aid is a mixture of 5-20 nm of silicon dioxide and titanium dioxide, and in the semiconduction process: the atmosphere is a reducing atmosphere, the temperature is 1380-1480 ℃, and the time is 1.5-3 hours; in the oxidation process: the atmosphere is air, the temperature is 1130-1280 ℃, and the time is 1-2 hours.

Preferably, in step S2, the coating thickness of the oxidant is 5 to 10 μm; the slurry of the oxidizing agent comprises the following components: 35% by weight of Bi₂O₃、25％CuO、10％B₂O₃、25％Li₂O₃、5％Al₂O₃。

Preferably, in step S1, the solid phase content in the ceramic slurry is 45 to 50 vol%, the particle size of the ceramic particles is 300 to 450nm, and the difference between the particle size of the ceramic particles and the wavelength of the exposure light source is 0 to 5 nm; the refractive index of the solvent is 1.4-1.5.

Preferably, the raw materials of the ceramic slurry comprise the following components: 45-50 parts of ceramic particles, 47-50 parts of solvent, 1-2 parts of oxide, 1-3 parts of polyethyleneimine-linolenic acid compound and 0.2-1 part of initiator by weight.

In the technical scheme, the three-dimensionality of the traditional planar ceramic blank, namely the channel structure of the ceramic dielectric layer, is realized mainly through a 3D printing technology, so that the electrode coverage area is increased under the condition of not increasing the whole size; the electrode spacing is reduced by utilizing the channel structure, and the capacity order of the single-layer ceramic capacitor is increased; meanwhile, the 3D printing process is utilized to prepare layer by layer, the traditional one-time forming process is changed, fine grains are improved, the grain boundary layer is shortened, the effect is obvious, the dielectric constant is improved by 30-50%, and the dielectric loss tg sigma is smaller than 1%.

(1) The channel adopts trapezoidal cross-section design cross-section, does not set up to the square, is in order to prevent to produce the right angle to prevent that perpendicular portion from sputtering the quality poor when electrode magnetron sputtering, it is thinner to form perpendicular thickness, has the risk of opening circuit. Therefore, the minimum included angle between two sides of the guaranteed depth and width is 65-85 ℃.

(2) The support column in the ceramic blank body is made of the same material as the ceramic medium layer; strontium titanate is used as a main phase; the support posts are present as device edges to provide positioning and support, as well as to prevent short circuiting of the die attach paste by spillage.

(3) The introduction of interval exposure-layering printing technology, the change of intensity before and after light source curing is utilized to solve the problem of layering gaps between layers and the problem of hardness and bonding strength of resin molding; the control precision is improved. Compared with the ceramic blank body which is printed in a one-time continuous mode, the ceramic blank body can further improve the distribution uniformity of ceramic grains, improve the fine grain degree of a fired product and shorten the spacing between grain boundary layers, so that the dielectric constant is improved, and the capacitance is improved.

(4) The content of the sintering aid accounts for 3-5% of the whole grain boundary layer ceramic blank, the compactness of the final device can be improved to 99%, and the sintering shrinkage rate of the device is reduced to about 5%. The oxidation process realizes crystal insulation, the oxidation time and the thickness of the ceramic blank have a certain proportional relation, and the difference in the scheme is small.

(5) In the ceramic slurry, the difference between the particle size and the wavelength of an exposure light source is limited, so that a maximum light scattering effect is generated during curing, and the accuracy of the curing depth is ensured; and meanwhile, a material with larger refractive index difference with the ceramic slurry is selected as a solvent, so that light scattering is increased. The reason is that: in the light curing process, the curing width and the curing depth are influenced by light scattering and have an inverse relation. Therefore, in the scheme, the grain size of the ceramic grains and the refractive index of the solvent are limited, so that the increase value of the curing width caused by the grain size and the refractive index difference of the material is smaller than the decrease value of the curing depth. So as to ensure higher resolution in the curing depth direction.

(6) The solvent in the ceramic slurry is acrylate resin, and meanwhile, a polyethyleneimine-linolenic acid compound is added as a dispersing agent. The preparation method of the polyethyleneimine-linolenic acid compound comprises the following steps: ultrasonically dispersing polyethyleneimine and linolenic acid with the mass ratio of 1 (1.5-2) in terpineol, and stirring for 20-24 hours to form a polyethyleneimine-linolenic acid compound with the concentration of 62-75 wt%.

Among them, the polyethyleneimine is adsorbed on the ceramic particles, and the long fatty chain of linolenic acid prevents severe aggregation caused by steric resistance, inhibiting aggregation of the ceramic particles. In the photocuring process, the resin is photopolymerized to release heat, so that an addition reaction is formed between acrylic ester and amino groups of polyethyleneimine, and meanwhile, part of primary amine in the polyethyleneimine reacts with unsaturated bonds in linolenic acid in photocuring, so that network is formed to induce photocuring of ceramic particles, and photocuring is promoted; the increase of the hardness and the bonding strength of resin molding is facilitated, and the sintering shrinkage rate of the device is inhibited.

Compared with the prior art, the invention has the beneficial effects that: (1) the ceramic blank with a three-dimensional structure is prepared through 3D printing, and after the electrode is subjected to magnetron sputtering, a structure similar to a multilayer ceramic capacitor is prepared, so that the increase of the area of the electrode and the reduction of the thickness of a ceramic medium under the same size are realized, the capacitance capacity is improved by 10-100 times, and the modulation range of a single-layer capacitor is greatly increased; (2) through the channel structure design, the thickness of the ceramic medium is reduced, so that in the process of carrying out semiconduction and crystal boundary layer oxidation, an ion diffusion channel is more sufficient, functional ions can be timely diffused into a crystal and on the surface of the crystal, the preparation uniformity of a device is improved, the preparation time is effectively reduced, and the dielectric constant is increased. (3) According to the invention, by adopting an indirect exposure-layer-by-layer printing technology, the distribution uniformity of ceramic grains is improved, the fine grain state and the shrinkage of a grain boundary layer are realized, and the dielectric constant is further increased.

Drawings

The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the principles of the invention and not to limit the invention. In the drawings:

fig. 1 is a side sectional view of a single layer capacitor in example 1;

FIG. 2 is a top view of the channel position of the single layer capacitor in example 1;

FIG. 3 is a top view of the channel position of the single layer capacitor in example 4;

FIG. 4 is a schematic view showing a trapezoidal sectional angle in the single layer capacitor in example 1;

in the figure: 1, a ceramic medium layer; 2, electroplating a copper layer; 3-1 upper electrode; 3-2 lower electrode; 4, a metal protective layer; 5, a support body; 6 intervals.

Detailed Description

The preferred embodiments of the present invention will be described in conjunction with the accompanying drawings, and it will be understood that they are described herein for the purpose of illustration and explanation and not limitation.

Example 1:

as shown in fig. 1-2, 4:

the single-layer capacitor comprises a ceramic dielectric layer 1 and a metal protection layer 4; the edge of the ceramic dielectric layer 1 extends out of the metal protective layer 4, and a support body 5 is formed on the epitaxial part; the upper surface and the lower surface of the ceramic dielectric layer 5 are respectively provided with an upper electrode 3-1 and a lower electrode 3-2 which are matched to form a channel structure; and an electroplated copper layer 2 is arranged between the channel structure and the metal protection layer 4.

The side surface of the channel structure forms an array type trapezoid cross section, and the angle range of the bottom angle A of the trapezoid is 80 ℃.

The preparation process comprises the following steps:

s1: placing the ceramic slurry in a DLP photocuring 3D printer, adopting an interval exposure-layered printing technology, setting the thickness of each layer of layered printing to be 5 microns, setting an exposure light source to be a pulse light source, setting the exposure time of each time to be 5 seconds, and setting the interval time to be 1 second, and printing to obtain a ceramic blank;

s2: degreasing the ceramic blank body at the high temperature of 700 ℃ for 2 hours; carrying out isostatic pressing treatment, filling a sintering aid, and degreasing again; setting the atmosphere as reducing atmosphere, temperature as 1400 deg.c and semiconductorizing for 2.5 hr; spraying an oxidant with the thickness of 6 mu m, setting the atmosphere as air and the temperature as 1200 ℃, and oxidizing for 1.5 hours; obtaining a grain boundary layer ceramic blank with a 40 mu m ceramic medium layer and a 160 mu m support body;

s3: sequentially sputtering TiW, Ni and Au on the upper surface and the lower surface of the ceramic dielectric layer respectively to form an upper electrode with the thickness of 1.5 mu m and a lower electrode with the thickness of 1.5 mu m; filling channels on the surfaces of the upper electrode and the lower electrode by using an electroplating copper solution respectively to form an electroplating copper layer; sequentially electroplating Ni and Au on the surface and the periphery of the electroplated copper layer to serve as a metal protective layer, wherein the support body is positioned on the outer side of the metal protective layer; a single layer ceramic capacitor was obtained.

In the technical scheme, the sintering aid is a mixture of 12nm silicon dioxide and titanium dioxide. The slurry of the oxidizing agent comprisesThe following components: 35% by weight of Bi₂O₃、25％CuO、10％B₂O₃、25％Li₂O₃、5％Al₂O₃. In the ceramic slurry, the solid phase content is 46.4 vol%, the particle size of the ceramic particles is 400nm, and the difference between the particle size of the ceramic particles and the wavelength of an exposure light source is 5 nm; the refractive index of the solvent was 1.45. The raw materials of the ceramic slurry comprise the following components: 45 parts of strontium titanate, 49 parts of pentaerythritol tetraacrylate, 2 parts of titanium dioxide-silicon dioxide nano mixed particles and 1 part of polyvinylpyrrolidone by weight.

Example 2:

as shown in fig. 1-2: the single-layer capacitor comprises a ceramic dielectric layer 1 and a metal protection layer 4; the edge of the ceramic dielectric layer 1 extends out of the metal protective layer 4, and a support body 5 is formed on the epitaxial part; the upper surface and the lower surface of the ceramic dielectric layer 5 are respectively provided with an upper electrode 3-1 and a lower electrode 3-2 which are matched to form a channel structure; and an electroplated copper layer 2 is arranged between the channel structure and the metal protection layer 4.

The side face of the channel structure forms an array type trapezoid cross section, and the angle range of a bottom angle A of the trapezoid is 65 ℃.

The preparation process comprises the following steps:

s1: placing the ceramic slurry in a DLP photocuring 3D printer, adopting an interval exposure-layered printing technology, setting the thickness of each layer of the layered printing to be 2 microns, setting an exposure light source to be a soft start light source, setting the exposure time of each time to be 5 seconds, and setting the interval time to be 1 second, and printing to obtain a ceramic blank;

s2: degreasing the ceramic blank body at a high temperature of 600 ℃ for 2 hours; carrying out isostatic pressing treatment, filling a sintering aid, and degreasing again; setting the atmosphere as reducing atmosphere, temperature 1380 deg.c and semiconductorizing for 1.5 hr; spraying an oxidant with the thickness of 5 mu m, setting the atmosphere as air and the temperature as 1130 ℃, and oxidizing for 1 hour; obtaining a grain boundary layer ceramic blank with a 30 mu m ceramic medium layer and a 120 mu m support body;

s3: sequentially sputtering TiW, Ni and Au on the upper surface and the lower surface of the ceramic dielectric layer respectively to form an upper electrode with the thickness of 1 micrometer and a lower electrode with the thickness of 1 micrometer; filling channels on the surfaces of the upper electrode and the lower electrode by using an electroplating copper solution respectively to form an electroplating copper layer; sequentially electroplating Ni and Au on the surface and the periphery of the electroplated copper layer to serve as a metal protective layer, wherein the support body is positioned on the outer side of the metal protective layer; a single layer ceramic capacitor was obtained.

In the technical scheme, the sintering aid is a mixture of 5nm of silicon dioxide and titanium dioxide. The slurry of the oxidizing agent comprises the following components: 35% by weight of Bi₂O₃、25％CuO、10％B₂O₃、25％Li₂O₃、5％Al₂O₃. In the ceramic slurry, the solid phase content is 50 vol%, the particle size of the ceramic particles is 300nm, and the difference between the particle size of the ceramic particles and the wavelength of an exposure light source is 1 nm; the refractive index of the solvent was 1.4. The raw materials of the ceramic slurry comprise the following components: by weight, 50 parts of strontium titanate, 47 parts of pentaerythritol tetraacrylate, 2 parts of titanium dioxide-silicon dioxide nano mixed particles and 1 part of polyvinylpyrrolidone.

Example 3:

as shown in fig. 1-2: the single-layer capacitor comprises a ceramic dielectric layer 1 and a metal protection layer 4; the edge of the ceramic dielectric layer 1 extends out of the metal protective layer 4, and a support body 5 is formed on the epitaxial part; the upper surface and the lower surface of the ceramic dielectric layer 5 are respectively provided with an upper electrode 3-1 and a lower electrode 3-2 which are matched to form a channel structure; and an electroplated copper layer 2 is arranged between the channel structure and the metal protection layer 4.

The side surface of the channel structure forms an array type trapezoid cross section, and the angle range of a bottom angle A of the trapezoid is 85 ℃.

The preparation process comprises the following steps:

s1: placing the ceramic slurry in a DLP photocuring 3D printer, adopting an interval exposure-layered printing technology, setting the thickness of each layer of layered printing to be 10 microns, setting an exposure light source to be a pulse light source, setting the exposure time of each time to be 5 seconds, and setting the interval time to be 1 second, and printing to obtain a ceramic blank;

s2: degreasing the ceramic blank body at the high temperature of 800 ℃ for 2 hours; carrying out isostatic pressing treatment, filling a sintering aid, and degreasing again; setting the atmosphere as reducing atmosphere at 1480 deg.c for semiconduction for 3 hr; spraying an oxidant with the thickness of 10 mu m, setting the atmosphere to be air and the temperature to be 1280 ℃, and oxidizing for 2 hours; obtaining a grain boundary layer ceramic blank with a 60 mu m ceramic medium layer and a 240 mu m support body;

s3: sequentially sputtering TiW, Ni and Au on the upper surface and the lower surface of the ceramic dielectric layer respectively to form an upper electrode with the diameter of 2 microns and a lower electrode with the diameter of 2 microns; filling channels on the surfaces of the upper electrode and the lower electrode by using an electroplating copper solution respectively to form an electroplating copper layer; sequentially electroplating Ni and Au on the surface and the periphery of the electroplated copper layer to serve as a metal protective layer, wherein the support body is positioned on the outer side of the metal protective layer; a single layer ceramic capacitor was obtained.

In the technical scheme, the sintering aid is a mixture of 20nm silicon dioxide and titanium dioxide. The slurry of the oxidizing agent comprises the following components: 35% by weight of Bi₂O₃、25％CuO、10％B₂O₃、25％Li₂O₃、5％Al₂O₃. In the ceramic slurry, the solid phase content is 48.5 vol%, the particle size of the ceramic particles is 450nm, and the difference between the particle size of the ceramic particles and the wavelength of an exposure light source is 5 nm; the refractive index of the solvent was 1.5. The raw materials of the ceramic slurry comprise the following components: by weight, 50 parts of strontium titanate, 50 parts of pentaerythritol tetraacrylate, 2 parts of titanium dioxide-silicon dioxide nano mixed particles and 1 part of polyvinylpyrrolidone.

Example 4:

as shown in fig. 3: the single-layer capacitor comprises a ceramic dielectric layer 1 and a metal protection layer 4; the edge of the ceramic dielectric layer 1 extends out of the metal protective layer 4, and a support body 5 is formed on the epitaxial part; the upper surface and the lower surface of the ceramic dielectric layer 5 are respectively provided with an upper electrode 3-1 and a lower electrode 3-2 which are matched to form a channel structure; and an electroplated copper layer 2 is arranged between the channel structure and the metal protection layer 4.

The side surface of the channel structure forms an array type trapezoid cross section, and the angle range of the bottom angle A of the trapezoid is 80 ℃.

The channel structures are arranged in a plurality of numbers, and adjacent channel structures are arranged in parallel and are separated by an interval 6.

The preparation process comprises the following steps:

s1: placing the ceramic slurry in a DLP photocuring 3D printer, adopting an interval exposure-layered printing technology, setting the thickness of each layer of layered printing to be 5 microns, setting an exposure light source to be a soft start light source, setting the exposure time of each time to be 5 seconds, and setting the interval time to be 1 second, and printing to obtain a ceramic blank;

s2: degreasing the ceramic blank body at the high temperature of 700 ℃ for 2 hours; carrying out isostatic pressing treatment, filling a sintering aid, and degreasing again; setting the atmosphere as reducing atmosphere, temperature as 1400 deg.c and semiconductorizing for 2.5 hr; spraying an oxidant with the thickness of 6 mu m, setting the atmosphere as air and the temperature as 1200 ℃, and oxidizing for 1.5 hours; obtaining a grain boundary layer ceramic blank with a 40 mu m ceramic medium layer and a 160 mu m support body;

s3: sequentially sputtering TiW, Ni and Au on the upper surface and the lower surface of the ceramic dielectric layer respectively to form an upper electrode with the thickness of 1.5 mu m and a lower electrode with the thickness of 1.5 mu m; filling channels on the surfaces of the upper electrode and the lower electrode by using an electroplating copper solution respectively to form an electroplating copper layer; sequentially electroplating Ni and Au on the surface and the periphery of the electroplated copper layer to serve as a metal protective layer, wherein the support body is positioned on the outer side of the metal protective layer; a single layer ceramic capacitor was obtained.

In the technical scheme, the sintering aid is a mixture of 12nm silicon dioxide and titanium dioxide. The slurry of the oxidizing agent comprises the following components: 35% by weight of Bi₂O₃、25％CuO、10％B₂O₃、25％Li₂O₃、5％Al₂O₃. In the ceramic slurry, the solid phase content is 46.4 vol%, the particle size of the ceramic particles is 400nm, and the difference between the particle size of the ceramic particles and the wavelength of an exposure light source is 3 nm; the refractive index of the solvent was 1.45. The raw materials of the ceramic slurry comprise the following components: 45 parts of strontium titanate, 49 parts of pentaerythritol tetraacrylate, 2 parts of titanium dioxide-silicon dioxide nano mixed particles and 1 part of polyvinylpyrrolidone by weight.

Example 5:

as shown in fig. 1-2: the single-layer capacitor comprises a ceramic dielectric layer 1 and a metal protection layer 4; the edge of the ceramic dielectric layer 1 extends out of the metal protective layer 4, and a support body 5 is formed on the epitaxial part; the upper surface and the lower surface of the ceramic dielectric layer 5 are respectively provided with an upper electrode 3-1 and a lower electrode 3-2 which are matched to form a channel structure; and an electroplated copper layer 2 is arranged between the channel structure and the metal protection layer 4.

The side surface of the channel structure forms an array type trapezoid cross section, and the angle range of the bottom angle A of the trapezoid is 80 ℃.

The preparation process comprises the following steps:

s1: placing the ceramic slurry in a DLP photocuring 3D printer, adopting an interval exposure-layered printing technology, setting the thickness of each layer of layered printing to be 5 microns, setting an exposure light source to be a pulse light source, setting the exposure time of each time to be 5 seconds, and setting the interval time to be 1 second, and printing to obtain a ceramic blank;

s2: degreasing the ceramic blank body at the high temperature of 700 ℃ for 2 hours; carrying out isostatic pressing treatment, filling a sintering aid, and degreasing again; setting the atmosphere as reducing atmosphere, temperature as 1400 deg.c and semiconductorizing for 2.5 hr; spraying an oxidant with the thickness of 6 mu m, setting the atmosphere as air and the temperature as 1200 ℃, and oxidizing for 1.5 hours; obtaining a grain boundary layer ceramic blank with a 40 mu m ceramic medium layer and a 160 mu m support body;

s3: sequentially sputtering TiW, Ni and Au on the upper surface and the lower surface of the ceramic dielectric layer respectively to form an upper electrode with the thickness of 1.5 mu m and a lower electrode with the thickness of 1.5 mu m; filling channels on the surfaces of the upper electrode and the lower electrode by using an electroplating copper solution respectively to form an electroplating copper layer; sequentially electroplating Ni and Au on the surface and the periphery of the electroplated copper layer to serve as a metal protective layer, wherein the support body is positioned on the outer side of the metal protective layer; a single layer ceramic capacitor was obtained.

In the technical scheme, the sintering aid is a mixture of 12nm silicon dioxide and titanium dioxide. The slurry of the oxidizing agent comprises the following components: 35% by weight of Bi₂O₃、25％CuO、10％B₂O₃、25％Li₂O₃、5％Al₂O₃. In the ceramic slurry, the solid phase content is 45 vol%, the particle size of the ceramic particles is 400nm, and the difference between the particle size of the ceramic particles and the wavelength of an exposure light source is 3 nm; the refractive index of the solvent was 1.45. The raw materials of the ceramic slurry comprise the following components: by weight, 45 parts of strontium titanate, 47 parts of pentaerythritol tetraacrylate and 1 part of titanium dioxide-silicon dioxide nanoMixed particles, 1 part of polyethyleneimine-linolenic acid compound and 1 part of 2-hydroxy-2-methyl-1-phenyl-1-acetone.

The preparation method of the polyethyleneimine-linolenic acid compound comprises the following steps: and ultrasonically dispersing polyethyleneimine and linolenic acid with the mass ratio of 1:1.8 in terpineol, and stirring for 24 hours to form a polyethyleneimine-linolenic acid compound with the concentration of 70 wt%.

Example 6: a single-layer capacitor was manufactured without using a 3D printing process with reference to a common process, in which a ceramic dielectric layer was prepared in a planar structure since a channel structure cannot be manufactured in the common process, and the rest was the same as in example 1.

Example 7: the ceramic medium layer was printed in a planar structure as usual, and the rest was the same as in example 1.

Experiment: carrying out performance tests on the single-layer capacitor prepared in the embodiment 1-8, wherein the performance tests comprise the shrinkage rate of a sintered device, the density of the capacitor, the dielectric constant and the dielectric loss; the data obtained were as follows:

examples	Density/%	Shrinkage ratio/%	Dielectric constant	Dielectric loss tg δ%
					Example 1	≥99	4.86	41802	0.37
Example 2	≥99	5.03	41506	0.46
					Example 3	≥99	4.99	41553	0.53
Example 4	≥99	4.92	41083	0.61
					Example 5	≥99	4.68	42137	0.30
Example 6	≥99	6.02	28090	2.01
					Example 7	≥99	4.90	37923	1.50

And (4) conclusion: from the data of examples 1 to 5, it can be seen that the density of the ceramic capacitor is 99%, the shrinkage rate is less than 5%, the dielectric constant is greater than 40000, and the dielectric loss is less than 1%; the single-layer ceramic capacitor prepared by the method solves the problems of small electrode area and low capacitance of the layer capacitor, improves the grain boundary layer forming quality of the grain boundary layer capacitor and further improves the device performance. In addition, comparing the data of example 1 and example 5, it can be seen that the replacement of the dispersant increases the dielectric constant and decreases the dielectric loss because the dispersant promotes the dispersion and forms a network during the photo-curing process to promote the photo-curing, thereby further suppressing the shrinkage of the grain boundary layer and further increasing the dielectric constant.

As can be seen from the data in comparative example 6: compared with a common process for preparing a planar single-layer ceramic capacitor, the single-layer capacitor with the channel structure prepared by the 3D printing process has the advantages that the performance is greatly improved, and the dielectric constant is improved by 40-50%. In combination with the data of example 7, it can be seen that the dielectric constant of the 3D printed planar capacitor is improved by about 30%. The reason is that: the channel structure realizes the increase of the area of the lower electrode and the reduction of the thickness of the ceramic dielectric in the same size, and greatly increases the modulation range of the single-layer capacitor; and 3D printing improves the distribution uniformity of ceramic grains, realizes the fine grain state and the shrinkage of a grain boundary layer, and further increases the dielectric constant.

Finally, it should be noted that: although the present invention has been described in detail with reference to the foregoing embodiments, it will be apparent to those skilled in the art that changes may be made in the embodiments and/or equivalents thereof without departing from the spirit and scope of the invention. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.