WO2022040987A1

WO2022040987A1 - Preparation method for thin-film capacitor, and thin-film capacitor

Info

Publication number: WO2022040987A1
Application number: PCT/CN2020/111447
Authority: WO
Inventors: 贾婷婷; 胡芳; 方伟; 丁振; 于淑会; 孙蓉
Original assignee: 中国科学院深圳先进技术研究院
Priority date: 2020-08-26
Filing date: 2020-08-26
Publication date: 2022-03-03

Abstract

Disclosed in the present application are a preparation method for a thin-film capacitor, and the thin-film capacitor. The preparation method comprises: providing a substrate; sequentially forming a sacrificial layer, a dielectric film layer, a first electrode layer and a capacitor base layer on the substrate; removing the substrate and the sacrificial layer; forming a second electrode layer on the side of the dielectric film layer away from the first electrode layer to obtain a thin-film capacitor structure; and packaging the thin-film capacitor by adopting a 3D printing technology. According to the method, the thin-film capacitor with high voltage resistance, long service life, stable temperature characteristic and low loss can be prepared, and can be applied to various related electronic devices, large-scale integrated circuits and the like.

Description

A kind of preparation method of film capacitor and film capacitor

【Technical field】

The present application relates to the field of preparation of electronic components, in particular to a preparation method of a film capacitor and a film capacitor.

【Background technique】

With the development of science and technology, the advent of the 5G era, and the development of the electronic information industry, the development of electronic devices has become more and more miniaturized, high-capacity, and breakdown-resistant.

The current market capacitors include ceramic capacitors, aluminum electrolytic capacitors, tantalum electrolytic capacitors and film capacitors. Among them, film capacitors often use plastic films such as polyethylene, polypropylene, polystyrene or polycarbonate as the dielectric layer, which have many excellent characteristics. Compared with ceramic capacitors, aluminum electrolytic capacitors, and tantalum electrolytic capacitors, Film capacitors with high dielectric constant inorganic materials as dielectric layers have the advantages of high withstand voltage, long life, stable temperature characteristics, and low loss. wiring part, thereby realizing lower impedance and wider frequency band.

[Content of the invention]

The main technical problem to be solved by the present application is to provide a method for preparing a film capacitor and a film capacitor, which can prepare a film capacitor with excellent properties such as high withstand voltage, long life, stable temperature characteristics, and low loss.

In order to solve the above technical problems, a first aspect of the present application provides a method for preparing a thin film capacitor, the method comprising: providing a substrate; forming a sacrificial layer, a dielectric thin film layer, and a first electrode layer in sequence on the substrate and capacitor base layer; wherein, the material of the substrate and the dielectric thin film layer are the same; remove the substrate and the sacrificial layer; on the side of the dielectric thin film layer away from the first electrode layer A second electrode layer is formed to obtain a thin film capacitor structure; the thin film capacitor structure is packaged by using 3D printing technology.

Optionally, the use of 3D printing technology to encapsulate the thin film capacitor structure includes:

A bottom module for placing the thin film capacitor structure is prepared by 3D printing technology, wherein the bottom module has a groove for placing the capacitor structure according to the size of the capacitor; the thin film capacitor structure is placed in the groove In the middle; using in-situ 3D printing technology, the top module is printed in-situ on the basis of the bottom module to complete the integrated packaging of the thin-film capacitor structure.

Optionally, before the in-situ printing of the top module on the basis of the bottom module, the method further includes: respectively preparing metal pins and/or metal leads on the first electrode layer and the second electrode layer.

Optionally, in the process of encapsulating the thin film capacitor structure by using the 3D printing technology, no additional adhesive is used, and high temperature curing is not required; before the encapsulating the thin film capacitor structure using the 3D printing technology, include : Precisely design the inner and outer shapes and structures of the bottom module and the top module according to the shape and structure of the thin film capacitor structure; the encapsulation layer of the top module corresponds to the encapsulation layer of the bottom module and has the same surface area, and the encapsulation layer The layer is larger than the capacitor structure size, so that when the film capacitor structure is packaged by 3D printing technology, the top module and the bottom module are seamlessly connected in situ, so that the top module and the bottom module form a seamless integrated package The module, the thin film capacitor structure, the metal pins and the packaging module form a unified whole.

In the 3D printing packaging method provided in this application, the bottom module and the top module of the 3D printing module are designed according to the film capacitor structure, the 3D packaging bottom module is printed on the periphery of the film capacitor structure, and the 3D printing process is used in-situ after embedding the film capacitor structure. Seamlessly build 3D package top modules.

Optionally, forming a sacrificial layer, a dielectric film layer, a first electrode layer and a capacitor base layer on the substrate in sequence includes: coating a first colloid on the substrate and placing it in the air heating to form a first precursor film; heating the first precursor film in oxygen to form the sacrificial layer; coating a second colloid on the sacrificial layer and heating in air to form a second precursor film; heating the second precursor film in oxygen to form the dielectric film layer; forming a first electrode layer and a capacitor base layer on the dielectric film layer.

Optionally, the coating of the first colloid on the substrate and heating in the air to form a first precursor film includes: spin-coating the first colloid on the substrate, placing the first colloid on the substrate The air is heated to a first preset temperature, and the first preset temperature is maintained for a first preset time, so that the first colloid forms the first precursor film.

Optionally, the heating of the first precursor film in oxygen to form the sacrificial layer includes: placing the first precursor film in a heating furnace in an oxygen atmosphere, and setting the oxygen flow rate as the first Presetting the flow rate of oxygen, heating to a second preset temperature, and maintaining the second preset temperature for a second preset time, so that the first precursor thin film forms the sacrificial layer.

Optionally, the step of coating a second colloid on the sacrificial layer and heating it in air to form a second precursor film includes: spin-coating the second colloid on the sacrificial layer, and placing it on the sacrificial layer. The air is heated to a third preset temperature, and the third preset temperature is maintained for a third preset time, so that the second colloid forms the second precursor film.

Optionally, the heating of the second precursor film in oxygen to form the dielectric film layer includes: placing the first precursor film in a heating furnace in an oxygen atmosphere, and setting the oxygen flow rate to The second preset oxygen flow rate is heated to a fourth preset temperature, and the fourth preset temperature is maintained for a fourth preset time, so that the second precursor film forms the dielectric film thin layer.

Optionally, the forming the first electrode layer and the capacitor base layer on the dielectric film layer includes: forming a first electrode layer on the dielectric film layer by ion sputtering; gluing the capacitor base layer on the first electrode layer.

Optionally, the first colloid is prepared by the following method: adding aluminum nitrate and strontium nitrate into nitric acid, and stirring to obtain a first solution; dissolving citric acid in water to obtain a second solution, and the amount of the citric acid greater than the sum of metal ions in the first solution; mixing the first solution and the second solution, heating and stirring to make the metal ions complex with the citric acid, and evaporating water to obtain the first solution colloid.

Optionally, the second colloid is prepared by the following method: mixing strontium acetate and glacial acetic acid, stirring to obtain a third solution, adding glacial acetic acid containing PVP to the third solution and stirring to obtain a fourth solution; Adding ethylene glycol methyl ether to tetrabutyl acid, stirring to obtain the fifth solution, adding acetylacetone to the fifth solution, stirring to obtain the sixth solution; mixing the fourth solution and the sixth solution, After stirring, ethylene glycol was added to the mixed solution, heated and stirred, cooled and filtered to obtain a second colloid.

Optionally, forming a sacrificial layer, a dielectric thin film layer, a first electrode layer and a capacitor base layer on the substrate in sequence includes: burning a first target with a pulsed laser to deposit on the substrate A sacrificial layer; a second target is burned with a pulsed laser to deposit a dielectric thin film layer on the sacrificial layer; a first electrode layer and a capacitor base layer are formed on the dielectric thin film layer.

Optionally, the using a pulsed laser to burn the first target to deposit a sacrificial layer on the substrate includes: placing the substrate and the strontium aluminate target in a reaction chamber of a pulsed laser deposition system; In the oxygen environment, the strontium aluminate target is burned by a pulsed laser to deposit strontium aluminate plasma on the substrate to form the sacrificial layer.

Optionally, the using a pulsed laser to burn the second target to deposit a dielectric thin film layer on the sacrificial layer includes: placing the strontium titanate substrate on which the sacrificial layer is prepared and the strontium titanate target material. in the reaction chamber of the pulsed laser deposition system; in the oxygen environment, the strontium titanate target is burned with a pulsed laser to deposit strontium titanate plasma on the substrate to form the dielectric thin film layer.

Optionally, the sacrificial layer is made of a hydrolyzable material; the removing the substrate and the sacrificial layer includes: including the substrate, the sacrificial layer, a dielectric film layer, and a first electrode layer And the material of the capacitor base layer is put into water to hydrolyze the sacrificial layer, so that the substrate is peeled off.

In order to solve the above technical problems, a second aspect of the present application provides a thin film capacitor prepared by the method for preparing a thin film capacitor provided in the first aspect.

The beneficial effects of the present application are: different from the situation in the prior art, the present application forms a sacrificial layer, a dielectric thin film layer, a first electrode layer and a capacitor base layer on the substrate in sequence, and then removes the sacrificial layer and the substrate, and then removes the sacrificial layer and the substrate. A second electrode layer is formed on the side of the electric thin film layer away from the first electrode layer to prepare a thin film capacitor. By preparing the first electrode layer and the second electrode layer after the dielectric thin film layer is prepared, the first electrode layer and the second electrode layer are not subjected to the high temperature environment during the preparation of the dielectric thin film layer, thereby avoiding high temperature oxidation of the electrode layer. , The prepared film capacitor has the characteristics of high withstand voltage, long life, stable temperature characteristics and low loss. The application also encapsulates the film capacitor structure through 3D printing technology, and does not use liquid adhesive in the whole process, which avoids the adverse effects on the capacitor structure due to high temperature curing or chemical corrosion in the traditional packaging process.

【Description of drawings】

In order to illustrate the technical solutions in the embodiments of the present application more clearly, the following briefly introduces the drawings that are used in the description of the embodiments. Obviously, the drawings in the following description are only some embodiments of the present application. For those of ordinary skill in the art, other drawings can also be obtained from these drawings without creative effort. in:

FIG. 1 is a schematic block diagram of a flow chart of an embodiment of a method for preparing a film capacitor of the present application;

FIG. 2 is a schematic flow diagram of steps S12 to S14 of the present application;

3 is a schematic block diagram of the flow of an embodiment of the 3D printing package of the present application;

FIG. 4 is a schematic flow diagram of an embodiment of the 3D printing package of the present application;

FIG. 5 is a schematic structural diagram of an embodiment of the bottom module of the present application

6 is a schematic diagram of a capacitor module prepared by a method for preparing a film capacitor in the present application;

7 is a schematic flow diagram of another embodiment of the method for preparing a film capacitor of the present application;

FIG. 8 is a schematic flow diagram of steps S22 to S26 of the present application;

FIG. 9 is a schematic structural diagram of another embodiment of the bottom module of the present application;

10 is a schematic structural diagram of another embodiment of the bottom module of the present application;

FIG. 11 is a schematic flowchart of another embodiment of steps S24 to S26 of the present application;

Fig. 12 is the XRD diffraction pattern of the film capacitor of the present application;

Fig. 13 is the surface topography diagram of the STO dielectric thin film layer of the present application;

Fig. 14 is the surface topography diagram of the SAO sacrificial layer of the present application;

Fig. 15 is the surface topography diagram of the STO substrate of the present application;

Figure 16a is a graph of the energy storage density of STO films with different thicknesses under a positive electric field;

Fig. 16b is a graph showing the variation of the relative permittivity εr of the film capacitor of the present application with the frequency f;

Figure 16c is a J-E curve diagram of the current-electric field of the film capacitor of the present application;

FIG. 16d is a graph showing the variation of the capacitance C and the loss factor tanδ of the film capacitor with the frequency f.

【detailed description】

The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, but not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by those of ordinary skill in the art without creative work, all belong to the scope of protection of this application.

The terms "first" and "second" in this application are only used for descriptive purposes, and should not be construed as indicating or implying relative importance or implicitly indicating the number of technical features shown. Thus, a feature delimited with "first", "second" may expressly or implicitly include at least one of that feature. Furthermore, the terms "comprising" and "having", and any conjugations thereof, are intended to cover non-exclusive inclusion. For example, a process, method, system, product or device comprising a series of steps or units is not limited to the listed steps or units, but optionally also includes unlisted steps or units, or optionally also includes For other steps or units inherent to these processes, methods, products or devices.

Reference herein to an "embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment can be included in at least one embodiment of the present application. The appearances of the phrase in various places in the specification are not necessarily all referring to the same embodiment, nor a separate or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

The core of the preparation method of the thin film capacitor of the present application is to introduce a sacrificial layer, so that the preparation step of the electrode of the thin film capacitor is followed by the preparation step of the dielectric thin film layer, so that the electrode layer is not subjected to the high temperature environment during the preparation of the dielectric thin film layer, and is free from High temperature oxidation, thereby improving the electrical performance of the capacitor, reducing losses, and extending the life of the capacitor.

Referring to FIG. 1 and FIG. 2 , FIG. 1 is a schematic flow diagram of an embodiment of a method for preparing a film capacitor of the present application, and FIG. 2 is a schematic flow diagram of steps S12 to S14 of the present application. The preparation method of this embodiment includes the following steps:

S11, providing a substrate.

The substrate 01 is used as the growth substrate layer of the sacrificial layer 02 and the dielectric thin film layer 03 in step S12, and the substrate 01 of the same material or different material as the dielectric thin film layer 03 can be selected according to actual requirements, which is not limited here.

S12, forming a sacrificial layer, a dielectric thin film layer, a first electrode layer and a capacitor base layer on the substrate in sequence.

In this step, first, a sacrificial layer 02 is formed on the substrate 01, and then a dielectric film layer 03 is formed on the side of the sacrificial layer 02 away from the substrate 01, and then a second layer is formed on the side of the dielectric film layer 03 away from the sacrificial layer 02. An electrode layer 04, and finally a capacitor base layer 05 is formed on the side of the first electrode layer 04 away from the dielectric film layer 03.

The sacrificial layer 02 is prepared from a hydrolyzable substance, for example, the sacrificial layer 02 may be a strontium aluminate thin film layer. Optionally, the first electrode layer 04 is copper or other metals with good electrical conductivity.

Wherein, the formation method of the sacrificial layer 02 includes, but is not limited to, a sol-gel method, a vapor deposition method, and a pulsed laser deposition method. The preparation method of the dielectric thin film layer 03 includes, but is not limited to, a sol-gel method, a vapor deposition method, and a pulsed laser deposition method. The preparation method of the first electrode layer 04 includes, but is not limited to, an electrodeposition method, an ion sputtering method, and the like.

Optionally, the material of the substrate 01 and the dielectric thin film layer 03 is the same. Specifically, the dielectric film layer 03 of the present application can be prepared from a single crystal material or a polycrystalline material. When a single crystal material is used to prepare the dielectric thin film layer 03, the substrate 01 is made of the same material as the dielectric thin film layer 03. Materials, using the homoepitaxial growth of the dielectric thin film layer 03, the high quality dielectric thin film layer 03 can be obtained.

Optionally, the steps of preparing the sacrificial layer 02 and the dielectric thin film layer 03 by a sol-gel method are as follows a1-d1:

a1. Coat the first colloid on the substrate 01, and heat it in the air to form the first precursor film.

b1. The first precursor film is heated in oxygen to form the sacrificial layer 02 .

c1. Coat the second colloid on the sacrificial layer and heat in air to form a second precursor film.

d1. The second precursor film is heated in oxygen to form the dielectric film layer 03 .

Specifically, when preparing the sacrificial layer 02, spin-coat the first colloid on the substrate 01, place it in the air and heat it to a first preset temperature, and maintain the first preset temperature for a first preset time, so that the first The colloid forms a first precursor film, and then the first precursor film is placed in a heating furnace in an oxygen atmosphere, the oxygen flow rate is set to a first preset oxygen flow rate, heated to a second preset temperature, and maintained for a second preset time. The second preset temperature enables the first precursor thin film to form the sacrificial layer 02 . When preparing the dielectric thin film layer 03, spin-coat the second colloid on the sacrificial layer 02, place it in the air and heat it to a third preset temperature, and maintain the third preset temperature for a third preset time, so that the first The two colloids form a second precursor film, and then the first precursor film is placed in a heating furnace in an oxygen atmosphere, the oxygen flow rate is set to the second preset oxygen flow rate, heated to a fourth preset temperature, and heated to a fourth preset time The fourth preset temperature is maintained, so that the second precursor thin film forms the dielectric thin film layer 03 .

The first colloid and the second colloid are the precursor colloids of the sacrificial layer 02 and the dielectric thin film layer 03, respectively. Optionally, when preparing the strontium aluminate sacrificial layer, the preparation steps of the first colloid are as follows a2-d2:

a2. adding aluminum nitrate and strontium nitrate to nitric acid and stirring to obtain the first solution;

b2. Dissolving citric acid in water to obtain a second solution, wherein the consumption of citric acid is greater than the sum of metal ions in the first solution;

c2. Mix the first solution and the second solution, heat and stir to make the metal ions complex with citric acid, and evaporate the water to obtain the first colloid.

Optionally, when preparing the strontium titanate single crystal dielectric thin film layer, the preparation steps of the second colloid are as follows a3-d3:

a3. Mix strontium acetate and glacial acetic acid, stir to obtain the third solution, add the glacial acetic acid containing PVP (polyvinylpyrrolidone) to the third solution and stir to obtain the fourth solution;

b3. adding tetrabutyl titanate to ethylene glycol methyl ether, stirring to obtain the fifth solution, adding acetylacetone in the fifth solution, stirring to obtain the sixth solution;

c3. Mix the fourth solution and the sixth solution, add ethylene glycol to the mixed solution after stirring, heat and stir, cool and filter to obtain the second colloid.

The above is only a schematic illustration of the preparation methods of the first colloid and the second colloid required for the preparation of the strontium aluminate sacrificial layer and the strontium titanate dielectric thin film layer. Those skilled in the art can perform the first colloid and the second colloid according to actual needs. configuration, which is not limited here.

In addition to preparing the sacrificial layer 02 and the dielectric thin film layer 03 by the above-mentioned sol-gel method, in another embodiment, the sacrificial layer 02 and the dielectric thin film layer 03 can also be prepared by using a pulsed laser deposition method, and the steps are as follows a4-b4 :

a4. Burn the first target with a pulsed laser to deposit the sacrificial layer 02 on the substrate 01;

b4. Burning the second target with a pulsed laser to deposit the dielectric thin film layer 03 on the sacrificial layer 02 .

Wherein, the first target can be a strontium aluminate target, and the second target can be a strontium titanate target. When preparing the sacrificial layer 02 and the dielectric film layer 03, the substrate 01 and the strontium aluminate target are placed In the reaction chamber of the pulsed laser deposition system, in the oxygen environment, the strontium aluminate target is burned by the pulsed laser to deposit the strontium aluminate plasma on the substrate to form the sacrificial layer 02; in the preparation of the dielectric thin film layer 03 When the strontium titanate substrate prepared with the sacrificial layer 02 and the strontium titanate target are placed in the reaction chamber of the pulsed laser deposition system, in the oxygen environment, the strontium titanate target is burned by the pulsed laser, so that the sacrificial strontium titanate Strontium titanate plasma is deposited on layer 02 to form dielectric thin film layer 03 .

Using the pulsed laser method to deposit the sacrificial layer 02 and the dielectric thin film layer 03 has high efficiency, and can prepare the sacrificial layer 02 and the dielectric thin film layer 03 with uniform thickness.

Optionally, the capacitor base layer 05 is glued on the side of the first electrode layer 04 away from the dielectric film layer 03 by adhesive.

S13, the substrate and the sacrificial layer are removed.

Specifically, to remove the substrate 01 and the sacrificial layer 02, the materials prepared in step S12, including the substrate 01, the sacrificial layer 02, the dielectric film layer 03, the first electrode layer 04 and the capacitor base layer 05, can be put into water , the sacrificial layer 02 is hydrolyzed to make the substrate 01 fall off, and the material including the dielectric thin film layer 03 , the first electrode layer 04 and the capacitor base layer 05 is obtained.

S14, forming a second electrode layer on the side of the dielectric thin film layer away from the first electrode layer to obtain a thin film capacitor structure.

Step S13 obtains the material including the dielectric thin film layer 03, the first electrode layer 04 and the capacitor base layer 05, and forms the second electrode layer 06 on the side of the dielectric thin film layer 03 away from the first electrode layer 04 to obtain the thin film capacitor structure 10 . The preparation method of the second electrode layer 06 can be prepared by electrodeposition, magnetron sputtering, ion sputtering or the like.

Optionally, using metal copper as the target, a copper layer is deposited on the side of the dielectric thin film layer 03 away from the first electrode layer 04 by ion sputtering, and the copper layer is used as the second electrode layer 06 .

S15, using 3D printing technology to encapsulate the film capacitor structure.

The thin film capacitor structure 10 obtained in step S14 may be encapsulated by epoxy resin, polyurethane, silicone resin, or the like.

3D printing technology is to install printing materials such as liquid or powder in the 3D printer. When printing, the printing materials are solidified and stacked layer by layer, and finally the blueprint on the computer is turned into a three-dimensional object.

In this embodiment, the 3D printing technology is used to package the film capacitor structure 10 , and the structure diagram of the package module can be precisely designed according to the size and shape of the film capacitor structure 10 in advance, so that the package module can be adapted to the size and shape of the film capacitor structure 10 , and then print the package. For the module, the film capacitor structure 10 is packaged in an integrated manner to obtain a highly integrated film capacitor, which can effectively simplify the packaging process and avoid errors in the bonding process.

Optionally, the structure of the film capacitor structure 10 is packaged by using 3D printing technology, please refer to FIG. 3 and FIG. 4 , FIG. 3 is a schematic block diagram of the flow of an embodiment of the 3D printing packaging of the present application, and FIG. 4 is a schematic diagram of the 3D printing packaging of the present application. A schematic flow diagram of the embodiment. The present embodiment uses the 3D printing technology to package the thin film capacitor structure 10 and specifically includes steps S151 to S153:

S151 , using 3D printing technology to prepare a bottom module for placing the thin film capacitor structure, wherein the bottom module has a groove adapted to the size of the thin film capacitor structure.

Please refer to FIG. 5 . FIG. 5 is a schematic structural diagram of a bottom module according to an embodiment of the present application. The bottom module 200 is provided with a groove 201 , and the groove 201 is adapted to the size design of the thin film capacitor structure 10 .

S152, placing the thin film capacitor structure in the groove.

The metal pins 1001 can be prepared on the first electrode layer 04 and the second electrode layer 06 before or after the thin film capacitor structure 10 is placed in the groove 201, and after the thin film capacitor structure 10 is placed in the groove 201, the metal leads The pins 1001 can extend beyond the packaging layer of the bottom module 200 (ie, the surface around the groove 201 that is connected to the top module during packaging), so that after the film capacitor structure 10 is packaged, the metal pins 1001 can be exposed in the package. outside the material.

S153, using in-situ 3D printing technology, prints the top module in-situ on the basis of the bottom module, and completes the integrated packaging of the film capacitor structure.

This step prints the top module to form the capacitor module 1000 shown in FIG. 6 . The first electrode layer 04 and the second electrode layer 06 in this embodiment are both prepared after the dielectric thin film layer 03 is prepared, and are not subjected to a high temperature environment, so as to avoid oxidation of the first electrode layer 04 and the second electrode layer 06 in the high temperature environment , effectively improve the performance of the capacitor, is conducive to prolonging the life of the capacitor, the process is simple, easy to implement. Capacitor module 1000 as shown in Figure 6 is obtained by encapsulating capacitors by 3D printing technology. Capacitor module 1000 has no assembly traces and has excellent sealing performance. Using 3D printing technology to encapsulate can effectively simplify the device preparation process, and reduce the reliability of the device due to complex processes such as metal interconnection. sexual influence.

Optionally, the inner and outer shapes and structures of the bottom module 200 and the top module (not shown) are precisely designed according to the shape and structure of the thin film capacitor structure 10 before 3D printing the package. Wherein, the encapsulation layer of the top module corresponds to the encapsulation layer of the bottom module 200 and has the same surface area, and the encapsulation layer is larger than the size of the capacitor structure, so that when the film capacitor structure 10 is encapsulated by 3D printing technology, the top module and the bottom module 200 are covered with a thin film The peripheral area of the capacitor structure 10 can be seamlessly connected in situ, so that the top module and the bottom module 200 form a seamless integrated package module, and the film capacitor structure 10, the metal pins 1001 and the package module form a unified whole.

Please refer to FIG. 7 and FIG. 8 , FIG. 7 is a schematic flowchart of another embodiment of the method for manufacturing a film capacitor of the present application, and FIG. 8 is a schematic flowchart of steps S22 to S26 of the present application, and the method for manufacturing a thin film capacitor in this embodiment is The steps include:

S21, providing a substrate.

The substrate 01 is used as the growth substrate layer of the sacrificial layer 02 and the dielectric thin film layer 03 in step S21, and the substrate 01 of the same material or different material as the dielectric thin film layer 03 can be selected according to actual needs, which is not limited here.

S22, forming a sacrificial layer, a dielectric thin film layer, a first electrode layer and a capacitor base layer on the substrate in sequence.

Wherein, the sacrificial layer 02 is prepared from a hydrolyzable substance.

S23, the substrate and the sacrificial layer are removed.

S24, containing the material including the dielectric thin film layer, the first electrode layer and the capacitor base layer into the bottom module.

S25, forming a second electrode layer on the side of the dielectric thin film layer away from the first electrode layer.

Please refer to FIG. 9. FIG. 9 is a schematic structural diagram of another embodiment of the bottom module of the present application. The bottom module 200 is provided with a groove 201. The side wall of the groove 200 is provided with at least one through hole 202, and one end of the through hole 202 is open. On the inner side of the side wall of the groove 200 , the opening at the other end is disposed in the same direction as the opening of the groove 200 , forming a curved through hole 202 . When the material including the dielectric film layer 03 , the first electrode layer 04 and the capacitor base layer 05 is placed in the bottom module 200 , the capacitor base layer 05 contacts the bottom of the groove 201 , and the dielectric film layer 03 is away from a portion of the first electrode layer 04 . The side is exposed, the first electrode layer 04 is exposed through the through hole 202, the second electrode layer 06 is deposited by ion sputtering on the exposed side of the dielectric film layer 03, and the metal lead 07 is deposited in the through hole 202, so that the metal One end of the lead 07 is connected to the first electrode layer 04, and the first electrode layer 04 can be connected to the metal pin 1001 through the metal lead 07 during packaging.

S26, using 3D printing technology, a complete package device is fabricated on the basis of the bottom module, so as to package the thin film capacitor structure.

In another embodiment, the bottom module can also be as shown in FIG. 10 . The bottom module 200 includes a groove 201 , and the sidewall of the groove 201 is provided with at least one first through hole 203 and at least one second through hole 204 .

Please refer to FIG. 11. FIG. 11 is a schematic flow diagram of another embodiment of steps S24-S26. In step S24, materials including the dielectric film layer 03, the first electrode layer 04 and the capacitor base layer 05 are placed in the bottom module 200 , the capacitor base layer 05 contacts the bottom of the groove 201 , the side of the dielectric film layer 03 away from the first electrode layer 04 is exposed, and the first electrode layer 04 is exposed through the through hole 203 . In step S25, the second electrode layer 06 is deposited on the exposed side of the dielectric thin film layer 03 by ion sputtering to form the thin film capacitor structure 10. After the 3D printing technology is used for encapsulation in step S26, the second electrode layer 06 is passed through the second pass. The hole 204 is exposed, the first electrode layer 04 is exposed through the first through hole 203, the metal pins 1001 are prepared in the first through hole 203 and the second through hole 204, respectively, and the first electrode layer 04 and the second electrode layer 06 are respectively Connect with the metal pins 1001 to obtain the packaged film capacitor module 1000 .

The bottom module 200 mentioned in the above embodiments is a schematic illustration, and those skilled in the art can design the size and shape of the bottom module and the top module of the package module according to actual needs, and are not limited to those shown in the above embodiments. way out.

Based on the above embodiments, the present application also provides a specific example of a method for preparing a film capacitor, and the preparation steps are as follows:

(1) An STO (SrTiO ₃ , strontium titanate) substrate is provided.

(2) The SAO (Sr ₂ Al ₆ O ₃ , strontium aluminate) sacrificial layer and the STO dielectric thin film layer are sequentially prepared by sol-gel method or pulsed laser deposition method.

Wherein, the preparation of the SAO sacrificial layer and the STO dielectric film layer by the sol-gel method specifically includes the following steps:

1) Prepare the SAO sacrificial layer, which specifically includes steps e1 to i1:

e1: Weigh aluminum nitrate, strontium nitrate and molar ratio of 3:1, add to nitric acid, add an appropriate amount of water, and stir at room temperature for 30 minutes;

f1: Dissolve citric acid in water, wherein the amount of citric acid is 1.2 to 1.3 times the sum of the metal ions to prepare a citric acid solution;

g1: Pour the nitrate mixed solution of metal ions into the citric acid solution, stir at 90°C to complete the complexation of metal ions and citric acid, and evaporate the water. Continue stirring until the solution becomes a viscous light yellow sol, and Finally, it is transformed into a viscous thick gel to obtain the SAO precursor sol;

h1: Coat the SAO precursor sol obtained in step g1 on the STO substrate, spin at 3000-6000r/min for 10-60s, place it in the air, heat it to 160°C on a heating table, and keep it for 30min to obtain SAO precursor film;

i1: Place the SAO precursor film obtained in step h1 in a heating furnace in an oxygen atmosphere with an oxygen flow rate of 1 L/min, raise the temperature to 1000° C. at a rate of 5-100° C./min, and hold for 120 min to obtain a SAO sacrificial layer.

2) Prepare the STO dielectric thin film layer, which specifically includes steps e2-i2:

e2: Preparation of strontium source: mix strontium acetate and glacial acetic acid, stir at 70～90℃ for 0.5～2h, slowly cool down to 40～60℃, add glacial acetic acid added with PVP, stir for 20～60min, wherein, strontium acetate: PVP=1mol : 3～8g, strontium acetate: total amount of acetic acid=1mol: 1.5～2.5L;

f2: Preparation of titanium source: Dissolve tetrabutyl titanate in ethylene glycol methyl ether, stir at 40-60 °C for 10-60 min, add acetylacetone, stir at 40-60 °C for 0.5-2 h, tetrabutyl titanate: ethylene glycol methyl ether Ether: acetylacetone=1mol: 2～3L: 0.08～0.12L;

g2: Slowly add the titanium source into the strontium source, 40-60°C, stir for 5-30min, add ethylene glycol, keep at 40-60°C, stir for 2-4h, cool to room temperature, filter the precursor solution to obtain the STO precursor sol . Among them, strontium source: ethylene glycol = 1 mol: 0.1 to 0.3 L.

h2: Coat the STO precursor sol obtained in step g2 on the side of the SAO sacrificial layer obtained from S4 far away from the STO substrate, spin at 3000-6000r/min for 10-60s, and place it in the air on a heating table The temperature is raised from 200°C to 300°C, then raised to 450°C, then cooled to 300°C, and finally lowered to 200°C, and kept for 5-10min each to obtain the STO precursor film;

i2: Place the STO precursor film obtained in step h2 in a heating furnace in an oxygen atmosphere, the oxygen flow rate is 1L/min, the temperature is raised to 450-500°C at a rate of 5-100°C/min, and the STO dielectric film is obtained by holding for 120min Floor.

The preparation of the SAO sacrificial layer and the STO dielectric thin film layer by the pulsed laser deposition method specifically includes steps e3 to g3:

e3: Put the STO substrate, strontium aluminate target, and strontium titanate target into the reaction chamber of the pulsed laser deposition system, and evacuate the reaction chamber;

f3: Fill the reaction chamber with oxygen to maintain the oxygen pressure at 50mTorr, set the energy of the laser to 250mJ and the frequency to 9.9Hz, set the substrate temperature to 600°C, make the laser emit laser light, and the number of dots is 18,000 times. Sintered on the strontium aluminate target, so that the strontium aluminate plasma is deposited on the strontium titanate substrate to form the SAO sacrificial layer.

g3: Adjust the oxygen in the reaction chamber to keep the oxygen pressure at 50mTorr, set the energy of the laser to 200mJ and the frequency to 9.9Hz, set the substrate temperature to 650°C, make the laser emit laser, the number of dots is 18000 times, and the cautery is at On the strontium titanate target, the strontium titanate plasma is deposited on the SAO sacrificial layer to form the STO dielectric thin film layer.

(3) A first copper electrode layer is deposited on the side of the STO dielectric thin film layer obtained in step (2) away from the SAO sacrificial layer by ion sputtering.

(4) The organic substrate PET is glued on the side of the first copper electrode layer away from the STO dielectric film layer, so that the PET substrate and the Cu electrode are fully contacted.

(5) The materials including the STO substrate, the SAO sacrificial layer, the STO dielectric film layer, the first copper electrode layer, and the PET substrate are immersed in water, so that the SAO sacrificial layer is hydrolyzed and the STO substrate falls off, thereby removing the SAO sacrificial layer and STO substrate to obtain the thin film capacitor structure 10 .

(6) The film capacitor structure 10 is placed in the groove 201 of the 3D printed mold 200, so that the PET substrate contacts the bottom of the groove 201, the side of the STO dielectric film layer away from the first copper electrode layer is exposed, and the first electrode The layers are exposed through the vias 202 of the mold 200 .

(7) A second copper electrode layer is deposited on the exposed side of the STO dielectric film layer by ion sputtering, and a copper wire is deposited in the through hole 202 at the same time, so that one end of the copper wire is connected to the first copper electrode layer.

(8) Encapsulation using 3D printing technology.

For the specific encapsulation process, reference may be made to the encapsulation steps in the above embodiments, and details are not described herein again.

Through the above steps (1) to (8), a high dielectric constant film capacitor module with excellent airtight performance is prepared. This module can be used as a single component or as an embedded capacitive component in combination with a large-scale integrated circuit, etc., and can be applied in a variety of devices.

Please refer to FIG. 12. FIG. 12 is the XRD diffraction pattern of the thin film capacitor of the present application, which shows that SAO thin film, SRO (SrRuO3) thin film and single crystal STO thin film are prepared.

Please refer to FIG. 13 , FIG. 14 and FIG. 15 together, FIG. 13 is the surface topography diagram of the STO dielectric film layer of the application, FIG. 14 is the surface topography diagram of the SAO sacrificial layer of the application, and FIG. 15 is the surface topography diagram of the STO lining layer of the application Bottom surface topography. The surface roughness value Ra of the STO dielectric film layer is 520pm, the surface roughness value Ra of the SAO sacrificial layer is 316pm, and the surface roughness value Ra of the STO substrate is 138pm, indicating that the prepared film is extremely smooth and meets the requirements of device applications. .

Please refer to Figures 16a, 16b, 16c and 16d together for the test results of the electrical properties of the film capacitor. Figure 16a shows the energy storage density of STO films with different thicknesses under a positive electric field, and Figure 16b shows the variation curve of the relative permittivity εr of film capacitors with frequency f. It can be seen that the relative permittivity of film capacitors is about the same as that of current commercial capacitors. 2 times that of the film. Figure 16c is the JE curve of the current-electric field of the film capacitor. It can be seen that the breakdown field strength of the film capacitor is about 6MV/cm2, which is about 1000 times that of the current industrial film. The capacitance C of the film capacitor and the change curve of the loss factor tanδ with the frequency f, the film capacitor prepared by this method has a lower dielectric loss.

The film capacitor prepared in this embodiment has high withstand voltage, long life, stable temperature characteristics, low loss, and the preparation process is simple and easy to implement, and can be prepared in large quantities.

The above description is only an embodiment of the present application, and is not intended to limit the scope of the patent of the present application. Any equivalent structure or equivalent process transformation made by using the contents of the description and drawings of the present application, or directly or indirectly applied to other related technologies Fields are similarly included within the scope of patent protection of this application.

Claims

A preparation method of a film capacitor, characterized in that the method comprises:

1) provide a substrate;

2) sequentially forming a sacrificial layer, a dielectric film layer, a first electrode layer and a capacitor base layer on the substrate;

3) removing the substrate and the sacrificial layer;

4) forming a second electrode layer on the side of the dielectric thin film layer away from the first electrode layer to obtain a thin film capacitor structure;

5) 3D printing technology is used to encapsulate the thin film capacitor structure.
The method of claim 1, wherein:

The use of 3D printing technology to encapsulate the thin film capacitor structure includes:

1) using 3D printing technology to prepare a bottom module for placing the thin film capacitor structure, wherein the bottom module has a groove adapted to the size of the thin film capacitor structure;

2) placing the thin film capacitor structure in the groove;

3) Using the in-situ 3D printing technology, the top module is printed in-situ on the basis of the bottom module to complete the integrated packaging of the thin film capacitor structure.
The method of claim 2, wherein:

Before the in-situ printing of the top module on the basis of the bottom module, the method further includes:

Metal pins and/or metal leads are prepared on the first electrode layer and the second electrode layer, respectively.
The method of claim 3, wherein:

In the process of encapsulating the thin film capacitor structure by using the 3D printing technology, no additional adhesive is used, and high temperature curing is not required;

Before encapsulating the thin-film capacitor structure using the 3D printing technology, it includes:

Precisely design the inner and outer shapes and structures of the bottom module and the top module according to the shape and structure of the thin film capacitor structure;

The encapsulation layer of the top module corresponds to the encapsulation layer of the bottom module and has the same surface area, and the encapsulation layer is larger than the size of the capacitor structure, so that when the film capacitor structure is packaged by 3D printing technology, the top module The in-situ seamless connection with the bottom module makes the top module and the bottom module form a seamless integrated package module, and the film capacitor structure, the metal pins and the package module form a unified whole.
The method of claim 1, wherein:

The step of sequentially forming a sacrificial layer, a dielectric film layer, a first electrode layer and a capacitor base layer on the substrate includes:

Coating a first colloid on the substrate and heating in air to form a first precursor film;

heating the first precursor film in oxygen to form the sacrificial layer;

Coating a second colloid on the sacrificial layer and heating in air to form a second precursor film;

heating the second precursor film in oxygen to form the dielectric film layer;

The first electrode layer and the capacitor base layer are formed on the dielectric thin film layer.
The method of claim 5, wherein:

The coating of the first colloid on the substrate and heating in the air to form the first precursor film includes:

The first colloid is spin-coated on the substrate, heated to a first preset temperature in air, and maintained at the first preset temperature for a first preset time, so that the first colloid is forming the first precursor film;

The heating of the first precursor film in oxygen to form the sacrificial layer includes:

The first precursor film is placed in a heating furnace in an oxygen atmosphere, the oxygen flow rate is set to a first preset oxygen flow rate, heated to a second preset temperature, and the second preset temperature is maintained for a second preset time. temperature, so that the first precursor film forms the sacrificial layer;

The coating of the second colloid on the sacrificial layer and heating in the air to form the second precursor thin film includes:

The second colloid is spin-coated on the sacrificial layer, heated to a third preset temperature in air, and maintained at the third preset temperature for a third preset time, so that the second colloid forming the second precursor film;

Said heating the second precursor film in oxygen to form the dielectric film layer, comprising:

The first precursor film is placed in a heating furnace in an oxygen atmosphere, the oxygen flow rate is set to a second preset oxygen flow rate, heated to a fourth preset temperature, and the fourth preset temperature is maintained for a fourth preset time. temperature so that the second precursor film forms the thin dielectric film layer.
The method of claim 5, wherein:

The forming the first electrode layer and the capacitor base layer on the dielectric film layer includes:

forming the first electrode layer on the dielectric thin film layer by ion sputtering;

The capacitor base layer is glued on the first electrode layer.
The method of claim 5, wherein:

The first colloid is produced by the following method:

Adding aluminum nitrate and strontium nitrate to nitric acid and stirring to obtain a first solution;

Dissolving citric acid in water to obtain a second solution, the consumption of the citric acid is greater than the sum of metal ions in the first solution;

The first solution and the second solution are mixed, heated and stirred so that the metal ions are complexed with the citric acid, and the water is evaporated to obtain the first colloid.
The method of claim 5, wherein:

The second colloid is produced by the following method:

Mix strontium acetate and glacial acetic acid, stir to obtain the third solution, add the glacial acetic acid containing PVP to the third solution and stir to obtain the fourth solution;

adding tetrabutyl titanate to ethylene glycol methyl ether, stirring to obtain the fifth solution, adding acetylacetone to the fifth solution, stirring to obtain the sixth solution;

Mixing the fourth solution and the sixth solution, adding ethylene glycol to the mixed solution after stirring, heating and stirring, cooling and filtering to obtain a second colloid.
The method of claim 1, wherein:

The step of sequentially forming a sacrificial layer, a dielectric film layer, a first electrode layer and a capacitor base layer on the substrate includes:

Burning the first target with a pulsed laser to deposit the sacrificial layer on the substrate;

Burning the second target with a pulsed laser to deposit the dielectric thin film layer on the sacrificial layer;

The first electrode layer and the capacitor base layer are formed on the dielectric thin film layer.
The method of claim 10, wherein:

The using pulsed laser to burn the first target material to deposit a sacrificial layer on the substrate includes:

placing the substrate and the strontium aluminate target in a reaction chamber of a pulsed laser deposition system;

In the environment of oxygen, the strontium aluminate target is burned by a pulsed laser to deposit strontium aluminate plasma on the substrate to form the sacrificial layer.
The method of claim 10, wherein:

The using pulsed laser to burn the second target material to deposit a dielectric thin film layer on the sacrificial layer includes:

placing the strontium titanate substrate prepared with the sacrificial layer and the strontium titanate target in the reaction chamber of the pulsed laser deposition system;

In an oxygen environment, the strontium titanate target material is burned by a pulsed laser to deposit strontium titanate plasma on the sacrificial layer to form the dielectric thin film layer.
The method of claim 1, wherein:

the sacrificial layer is made of a hydrolyzable material;

The removing the substrate and the sacrificial layer includes:

The materials including the substrate, the sacrificial layer, the dielectric thin film layer, the first electrode layer and the capacitor base layer are put into water to hydrolyze the sacrificial layer, so that the substrate is peeled off.
A film capacitor, characterized in that:

The film capacitor is prepared by the method according to any one of claims 1 to 13.