CN114446661B - A kind of multilayer ceramic capacitor based on chemical mechanical polishing and its preparation method - Google Patents

Abstract

The present application provides a multilayer ceramic capacitor based on chemical mechanical polishing and a method for manufacturing the same by growing SiO on a substrate ₂ The sacrificial layer and the ceramic film layer are respectively subjected to chemical mechanical polishing and electrode sputtering, the two ceramic film layers are bonded, and then SiO is corroded ₂ The sacrificial layer releases the ceramic film layer, the electrodes are sputtered at the two ends of the released ceramic film layer, and the electrodes at the two ends of the ceramic film layer are immersed and sealed after repeated for a plurality of times and then calcined at high temperature, so that the multilayer ceramic capacitor is obtained. The method combines chemical mechanical polishing and indirect bonding to realize the manufacture of the multilayer ceramic capacitor, avoids temperature control in the process flow of a tape casting method, can realize the preparation of the ceramic film at normal temperature, reduces adverse effects on the film quality and performance in the processes of high temperature, cooling and drying, and obtains the piezoelectric ceramic film with high quality, low stress and high density; the high-temperature sintering process is not needed, the operation temperature is lower, and the yield of the ceramic film is ensured.

Description

A kind of multilayer ceramic capacitor based on chemical mechanical polishing and its preparation method

technical field

The application belongs to the technical field of MEMS device processing and manufacturing, and in particular relates to a multilayer ceramic capacitor based on chemical mechanical polishing and a preparation method thereof.

Background technique

With the development of electronic technology, electronic devices and circuits are developing towards miniaturization and integration. Capacitors, as an energy storage component, are the most widely used and the largest amount of electronic components in electronic equipment, and their output accounts for about the total amount of electronic components. 40%, widely used in DC blocking, coupling, bypass, filtering, tuning loop, energy conversion and control circuits, etc. Among them, Multilayer Ceramic Capacitor (MLCC, Multilayer Ceramic Capacitor) is the most important member of the capacitor family and one of the most widely used passive devices at present. It is widely used in military complete machines such as aerospace, aviation, weapons, and ships. Among the models, the reliability of MLCC is one of the foundations for the reliability guarantee of the whole machine; while the internal electrode slurry is one of the main structural materials of MLCC, the quality of the internal electrode and related processes directly determine the inherent reliability of MLCC. In order to meet the requirements of circuit miniaturization and high-density assembly, in medium and high voltage circuits such as voltage doubler power supply circuits, automotive electronic equipment, network interfaces, and light source drivers, multilayer ceramic capacitors are used for their small size, high withstand voltage, and high reliability. , suitable for surface mount and other advantages, the usage is increasing, especially for mobile communication products, computers, digital cameras, and a new generation of digital home appliances. The demand for MLCC products is increasing day by day, and as electronic products tend to With the increasing popularity of light, thin, short, small and surface mount technology, the development of MLCC has more potential. As China increasingly becomes the world's major manufacturing base for electronic information products, the total domestic MLCC market demand is showing a rapid growth trend, providing good opportunities for the development of domestic MLCC enterprises.

At present, the commonly used method of manufacturing MLCC is the casting method. The process of preparing the film by the casting method is to first add the ceramic powder and the dispersant to the solvent, then add the binder and the plasticizer, and obtain the slurry through two ball mills. After vacuum defoaming, filtration and other processes are formed, it is coated with a scraper on the running film belt and dried to obtain a film. The whole process of the tape casting method adopts vertical operation, the operation is slightly complicated and difficult, the thickness is uneven, and stress residue is prone to exist. Because the addition of binder during the process will cause the diaphragm to warp, the binder covering the ceramic powder particles will migrate to the surface of the green sheet with the volatilization of the solvent during the drying process and dry into a polymer film, blocking the internal volume of the green sheet Channels that diffuse to the surface cause inconsistent drying shrinkage at the edges and middle, warping occurs. The presence of stress shrinkage during drying can also cause warping of the diaphragm. Incomplete vacuum defoaming will lead to spot vacuum in the diaphragm; uneven dispersion of slurry will produce too thick or too thin linear stripes. During the doctor blade coating process, the slight difference in the height of the doctor blade will also cause the thickness of the film to be uneven, and even have a greater impact on the properties of the film such as d ₃₃ and density. It is difficult to control the casting speed in the casting process. If the casting speed is too fast, the membrane cannot be formed; if the casting speed is too slow, although a complete ceramic membrane can be produced, it will affect the ferroelectric properties of the membrane, which will make the d ₃₃ low. . The tape-casting method also has the influence of ferroelectric properties such as high coercive field.

Contents of the invention

In view of this, the application provides a multilayer ceramic capacitor based on chemical mechanical polishing and its preparation method, which can avoid problems such as uneven film thickness and low device performance when preparing multilayer ceramic capacitors by tape casting , and then realize the device preparation with high flatness, high performance and high yield at lower temperature.

The concrete technical scheme of this application is as follows:

The application provides a method for preparing a multilayer ceramic capacitor based on chemical mechanical polishing, comprising the following steps:

Clean the substrate, and grow _SiO2 sacrificial layer and ceramic thin film layer on the substrate in turn;

Carry out chemical mechanical polishing and sputtering electrodes on the ceramic thin film layers respectively, and bond the two ceramic thin film layers;

Etching the _SiO sacrificial layer to release the ceramic film layer, and sputtering electrodes at both ends of the released ceramic film layer;

The two ends of the ceramic film layer after the sputtering electrode are repeatedly bonded;

The electrodes at both ends of the ceramic film layer are impregnated and calcined at high temperature to obtain a multilayer ceramic capacitor.

Preferably, the substrate is a sapphire substrate, the material of the ceramic film is selected from CaSrZrO ₃ , BaTiO ₃ or BaSrTiO ₃ , and the material of the electrode is selected from Au or Pt. More preferably, the material of the ceramic thin film is selected from BaTiO ₃ , and the material of the electrode is selected from Au.

Preferably, cleaning the substrate is specifically:

After cleaning the substrate with acetone, alcohol and deionized water in sequence, the substrate is subjected to high-temperature annealing treatment.

Preferably, the vapor deposition growth method is used to grow the SiO ₂ sacrificial layer to a thickness of 400-600 nm, and to grow the ceramic thin film layer to a thickness of 2-5 μm. More preferably, the thickness of the grown SiO ₂ sacrificial layer is 500 nm, and the thickness of the grown ceramic thin film layer is 4 μm.

Preferably, the material of the polishing pad used in chemical mechanical polishing is polyurethane, the abrasive of the polishing liquid is selected from SiO ₂ , the particle size of the abrasive of the polishing liquid is 40-60 nm, and the rotational speed of the polishing disc is 50-80 r/min. More preferably, the particle size of the abrasive in the polishing liquid is 50 nm, and the rotational speed of the polishing disc is 70 r/min.

Preferably, the sputtering electrode uses a magnetron sputtering method, and the thickness of the sputtering electrode is 100-300 nm. More preferably, the sputtering electrode has a thickness of 200 nm.

Preferably, the bonding temperature of the ceramic film layer is 200-250° C., the pressure is 1-3 kN, and the bonding time is 6-10 hours. More preferably, the bonding temperature of the ceramic film layer is 230° C., the pressure is 2 kN, and the bonding time is 8 hours.

Preferably, the impregnating solution for impregnating the electrodes at both ends is silver paste with a mass fraction of 70-90wt%;

The temperature of the high-temperature calcination is 500-800° C., and the time is 60-80 minutes. More preferably, the impregnating solution for impregnating the electrodes at both ends is silver paste with a mass fraction of 79 wt %; the temperature for high-temperature calcination is 600° C., and the time is 60 minutes.

The present application also provides a multilayer ceramic capacitor based on chemical mechanical polishing, which is prepared by the method for preparing a multilayer ceramic capacitor based on chemical mechanical polishing.

Preferably, the diameter of the ceramic film layer is greater than or equal to 5 cm, the thickness is less than or equal to 5 μm, and the thickness of the sputtered metal electrode is greater than or equal to 100 nm.

The application provides a multilayer ceramic capacitor based on chemical mechanical polishing and a preparation method thereof. By growing a _SiO2 sacrificial layer and a ceramic thin film layer on a substrate, the ceramic thin film layer is chemically mechanically polished and the electrodes are sputtered, and the two Block ceramic film layers are bonded, corroded _SiO sacrificial layer to release the ceramic film layer, sputtering electrodes at both ends of the released ceramic film layer, after many repetitions, and finally impregnating the electrodes at both ends of the ceramic film layer and calcining at high temperature to obtain multilayer ceramic capacitors. This application combines the method of chemical mechanical polishing and indirect bonding to realize the manufacture of multilayer ceramic capacitors. The method of chemical mechanical polishing is used instead of the conventional casting method, which avoids the temperature control in the process flow of the casting method, and can be used in The preparation of ceramic thin films at room temperature reduces the adverse effects of high temperature, cooling and drying on the film quality and performance, and obtains high-quality, low-stress, high-density piezoelectric ceramic thin films; no high-temperature sintering process is required, and more Low operating temperature ensures the yield of ceramic thin film. The chemical-mechanical polishing-based multilayer ceramic capacitor and its preparation method of the present application can be applied to the manufacture of integrated circuits, and the design of back-end circuits such as micro-sensors and micro-actuators.

Description of drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings that need to be used in the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description are only These are some embodiments of the present application. Those skilled in the art can also obtain other drawings based on these drawings without any creative effort.

Fig. 1 is the preparation method flowchart of multilayer ceramic capacitor in the embodiment of the present application;

Fig. 2 is the cross-sectional structure schematic diagram after the growth film of the multilayer ceramic capacitor preparation method in the embodiment of the present application;

FIG. 3 is a schematic cross-sectional structure diagram after polishing of the multilayer ceramic capacitor preparation method in the embodiment of the present application;

Fig. 4 is the schematic cross-sectional structure diagram after the sputtering electrode of the multilayer ceramic capacitor preparation method in the embodiment of the present application;

FIG. 5 is a schematic cross-sectional structure diagram after bonding of the multilayer ceramic capacitor manufacturing method in the embodiment of the present application;

6 is a schematic diagram of a cross-sectional structure after corrosion by the method for preparing a multilayer ceramic capacitor in the embodiment of the present application;

Fig. 7 is a schematic cross-sectional structure diagram of the multilayer ceramic capacitor manufacturing method in the embodiment of the present application after repeated bonding;

Fig. 8 is a schematic cross-sectional structure diagram of the multilayer ceramic capacitor preparation method in the embodiment of the present application after impregnation;

Illustration: 1. Substrate; 2. SiO ₂ sacrificial layer; 3. Ceramic film; 4. Metal electrode; 5. Metal terminal electrode.

Detailed ways

Referring to FIG. 1 , FIG. 1 is a flowchart of a method for preparing a multilayer ceramic capacitor in an embodiment of the present application.

The embodiment of the present application provides a method for preparing a multilayer ceramic capacitor based on chemical mechanical polishing, including the following steps:

S1: Clean the substrate, and grow a SiO ₂ sacrificial layer and a ceramic thin film layer on the substrate in turn;

S2: Carry out chemical mechanical polishing and sputtering electrodes on the ceramic thin film layers respectively, and bond the two ceramic thin film layers;

S3: corrode the _SiO2 sacrificial layer to release the ceramic film layer, and sputter electrodes at both ends of the released ceramic film layer;

S4: repeatedly bond the two ends of the ceramic thin film layer after the sputtering electrode;

S5: impregnating the electrodes at both ends of the ceramic thin film layer and calcining at high temperature to obtain a multilayer ceramic capacitor.

It should be noted that the preparation of ceramic thin films can be realized at room temperature through chemical mechanical polishing, which reduces the adverse effects of high temperature, cooling and drying processes on the quality and performance of the thin films, and obtains high-quality, low-stress, high-density compacted films. Electroceramic thin film; the indirect bonding method does not require a high-temperature sintering process, and has a lower operating temperature, which ensures the yield of the ceramic thin film. Combining the chemical mechanical polishing and indirect bonding of the present application can realize device preparation with high flatness, high performance and high yield at a relatively low temperature.

With reference to Fig. 2～8, Fig. 2 is the cross-sectional structure schematic diagram after the film growth of the multilayer ceramic capacitor preparation method in the embodiment of the present application; Fig. 3 is the cross-sectional structural schematic diagram after the polishing of the multilayer ceramic capacitor preparation method in the embodiment of the present application; Fig. 4 is a schematic diagram of the cross-sectional structure of the multilayer ceramic capacitor preparation method in the embodiment of the application after sputtering electrodes; Fig. 5 is a schematic diagram of the cross-sectional structure of the multilayer ceramic capacitor preparation method in the embodiment of the application after bonding; Fig. 6 is the embodiment of the application The schematic diagram of the cross-sectional structure of the multilayer ceramic capacitor preparation method after corrosion in the example; Figure 7 is the cross-sectional schematic diagram of the multi-layer ceramic capacitor preparation method in the embodiment of the application after repeated bonding; Figure 8 is the multi-layer ceramic capacitor in the embodiment of the application Schematic diagram of the cross-sectional structure of the ceramic capacitor after impregnation.

The preparation method of the multilayer ceramic capacitor based on chemical mechanical polishing in the embodiment of the present application firstly cleans the substrate 1 and then grows _SiO2 sacrificial layer 2 and ceramic thin film layer 3 on the substrate successively, and uses chemical mechanical polishing to polish the ceramic thin film layer 3 to make it smooth. And the metal electrode 4 is sputtered on the surface of the ceramic thin film layer 3, and the two ceramic thin film layers 3 are bonded. Utilize reagent to corrode SiO _Sacrificial layer ceramic thin film layer 3 is released from substrate 1, sputter metal electrode 4 to the ceramic thin film layer 3 two ends after releasing again, after sputtering metal electrode, the two ends of ceramic thin film layer 3 are carried out The bonding is repeated many times, and finally the metal electrodes at both ends of the ceramic film layer 3 are impregnated to obtain the metal terminal electrodes 5, which are calcined at a high temperature to obtain a multilayer ceramic capacitor.

According to an embodiment of the present application, the substrate is a sapphire substrate, the material of the ceramic thin film is selected from CaSrZrO ₃ , BaTiO ₃ or BaSrTiO ₃ , and the material of the electrode is selected from Au or Pt.

According to the embodiment of the present application, cleaning the substrate is specifically:

After cleaning the substrate with acetone, alcohol and deionized water in sequence, the substrate is subjected to high-temperature annealing treatment.

It should be noted that the purpose of substrate cleaning is to remove surface particles to provide a smooth and clean surface for subsequent thin film preparation.

According to the embodiment of the present application, the thickness of the grown SiO ₂ sacrificial layer is 400-600 nm, and the thickness of the grown ceramic thin film layer is 2-5 μm by using the vapor deposition growth method.

It should be noted that the grown SiO ₂ sacrificial layer is used to separate the sapphire substrate from the ceramic thin film in the later process, and the grown ceramic thin film layer can be used as the dielectric layer of the capacitor.

According to the embodiment of the present application, the material of the polishing pad used in chemical mechanical polishing is polyurethane, the abrasive of the polishing liquid is selected from SiO ₂ , the particle size of the abrasive of the polishing liquid is 40-60 nm, and the rotational speed of the polishing disc is 50-80 r/min.

It should be noted that the chemical mechanical polishing method used in this application is simpler in process than the tape-casting method in which the whole process is vertical, with fewer factors affecting film quality, easier control of film thickness, and smoother, smoother films. Higher precision. The chemical mechanical polishing method used in this application does not require temperature control, which reduces the adverse effects of high temperature, cooling and drying processes on film quality and performance. The chemical mechanical polishing method of the present application uses a chemical mechanical thinning polishing method, while the tape casting method uses a film growth mechanism, so the prepared film has better density and can reduce stress residue during the manufacturing process. Therefore, the chemical mechanical polishing method of the present application can produce large flatness processing, and can ensure the complete elimination of processing surface damage and residual stress to meet the requirements of surface integrity and functional integrity. In addition, the materials used in the chemical mechanical polishing method of the present application are non-toxic and will not cause harm to humans and the environment.

According to an embodiment of the present application, a magnetron sputtering method is used for the sputtering electrode, and the thickness of the sputtering electrode is 100-300 nm.

It should be noted that sputtered metal electrodes can be used as internal plates of capacitors.

According to the embodiment of the present application, the bonding temperature of the ceramic film layer is 200-250° C., the pressure is 1-3 kN, and the bonding time is 6-10 hours.

It should be noted that the capacitor unit structure can be obtained after the ceramic film layers are bonded.

According to the embodiment of the present application, the impregnating solution for impregnating the electrodes at both ends is silver paste with a mass fraction of 70-90wt%;

The temperature of the high-temperature calcination is 500-800° C., and the time is 60-80 minutes.

It should be noted that the terminal electrode after sealing contains organic components and does not have the basic function of external electrodes. It needs to undergo high-temperature firing treatment to completely decompose the organic components in the terminal electrodes. The terminal electrodes are sintered densely and the internal and external electrodes are well combined. , so it has the basic function of connecting the internal electrodes.

The embodiment of the present application also provides a multilayer ceramic capacitor based on chemical mechanical polishing, which is prepared by the method for preparing a multilayer ceramic capacitor based on chemical mechanical polishing.

It should be noted that the piezoelectric ceramic thin film of the present application has the characteristics of high quality, low stress, and high density, and the multilayer ceramic capacitor of the present application realizes device preparation with high flatness, high performance, and high yield.

It should be noted that the diameter of the ceramic film layer is greater than or equal to 5 cm, the thickness is less than or equal to 5 μm, and the thickness of the sputtered metal electrode is greater than or equal to 100 nm.

In order to make the purpose, features and advantages of the present application more obvious and understandable, the technical solutions in the embodiments of the present application are clearly and completely described. Obviously, the embodiments described below are only part of the embodiments of the present application, and Not all examples. Based on the embodiments in this application, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the scope of protection of this application.

The reagents and raw materials used in the examples of this application are all commercially available or self-made.

Example 1

Step 1: After cleaning the substrate with acetone, alcohol and deionized water in sequence, perform high-temperature annealing treatment on the substrate. Use the vapor deposition method to grow _SiO2 with a thickness of 500nm on the surface of sapphire as a sacrificial layer, which is used to separate the sapphire substrate from the ceramic film in the later process; continue to use the vapor deposition method to grow a _BaTiO3 film with a thickness of 4 μm on the surface of _SiO2 , As the dielectric layer of the capacitor;

Step 2: Spin-coat the glass substrate twice with photoresist AZ4620, put it into the temporary bonding machine at the same time as the sapphire substrate with the film grown, apply a pressure of 2 bar and a temperature of 40°C for 30 minutes to complete the temporary bonding of the sapphire substrate , use model No. 0CON-137 SF1 polishing solution to polish the BaTiO ₃ film, use polyurethane as the polishing pad material during polishing, the abrasive of the polishing solution is selected from SiO ₂ , the particle size of the abrasive of the polishing solution is 50nm, and the speed of the polishing disc is 70r /min, the quality of the polishing fixture is 5kg, continuous polishing 1.5h obtains a smooth BaTiO ₃ film;

Step 3: Use ultraviolet exposure technology to transfer the pattern to the surface of the BaTiO ₃ film, then use magnetron sputtering to grow Au with a thickness of 200 nm on the surface of the developed BaTiO ₃ film as the internal pole plate of the capacitor, and then use EVG520 to process the two films Bonding, the temperature during bonding is 230°C, the pressure is 2kN, the bonding time is 8h, and the capacitor unit structure is obtained;

Step 4: use hydrofluoric acid (49wt%) to corrode the SiO ₂ sacrificial layer, release the BaTiO ₃ film structure, and sputter electrodes at both ends, repeat steps 1 to 3 to complete the internal capacitance structure of the capacitor, and prepare the multilayer ceramic The film is cut into a size of 0.2cm*0.5cm, and the electrodes at both ends are impregnated with silver paste with a mass fraction of 75wt%. The silver terminal electrode air sintering technology mainly adopts a chain-type terminal electrode sintering furnace with a temperature of 600°C and a time of 60 minutes.

Using an atomic force microscope to test the surface morphology of the polished ceramic film, the measured Ra value is 425pm, and the capacitance change rate of the obtained multilayer ceramic capacitor is 0±30ppm/°C under the condition of -50°C-125°C, and the capacity is at high Under frequency conditions, the rate of change with frequency is less than ±0.3% ΔC, the capacity drift or hysteresis is less than ±0.05%, and the change of capacity relative to life is less than ±0.1%.

Example 2

Step 1: After cleaning the substrate with acetone, alcohol and deionized water in sequence, perform high-temperature annealing treatment on the substrate. Use the vapor deposition method to grow _SiO2 with a thickness of 500nm on the surface of sapphire as a sacrificial layer, which is used to separate the sapphire substrate from the ceramic film in the later process; continue to use the vapor deposition method to grow a _CaSrZrO3 film with a thickness of 4 μm on the surface of _SiO2 , As the dielectric layer of the capacitor;

Step 2: Spin-coat the glass substrate twice with photoresist AZ4620, put it into the temporary bonding machine at the same time as the sapphire substrate with the film grown, apply a pressure of 2 bar and a temperature of 40°C for 30 minutes to complete the temporary bonding of the sapphire substrate , use model No. 0CON-137 SF1 polishing solution to polish the CaSrZrO ₃ film, use polyurethane as the polishing pad material during polishing, the abrasive of the polishing solution is selected from SiO ₂ , the particle size of the abrasive of the polishing solution is 50nm, and the speed of the polishing disc is 70r /min, the quality of the polishing fixture is 5kg, continuous polishing 1.5h obtains a smooth BaTiO ₃ film;

Step 3: Use ultraviolet exposure technology to transfer the pattern to the surface of the CaSrZrO ₃ film, then use magnetron sputtering to grow Au with a thickness of 200 nm on the surface of the developed CaSrZrO ₃ film as the internal pole plate of the capacitor, and then use EVG520 to process the two films Bonding, the temperature during bonding is 230°C, the pressure is 2kN, the bonding time is 8h, and the capacitor unit structure is obtained;

Step 4: use hydrofluoric acid (49wt%) to corrode the _SiO2 sacrificial layer, release the _CaSrZrO3 film structure, and sputter the electrodes at both ends, repeat steps 1 to 3 to complete the internal capacitance structure of the capacitor, and prepare the multilayer ceramic The film is cut into a size of 0.2cm*0.5cm, and the electrodes at both ends are impregnated with silver paste with a mass fraction of 75wt%. The silver terminal electrode air sintering technology mainly adopts a chain-type terminal electrode sintering furnace with a temperature of 600°C and a time of 60 minutes.

Using an atomic force microscope to test the surface morphology of the polished ceramic film, the measured Ra value is 420pm, and the obtained multilayer ceramic capacitor has a capacitance change rate of 0±40ppm/°C under the condition of -50°C-125°C, and the capacity is at high Under frequency conditions, the rate of change with frequency is less than ±0.5% ΔC, the capacity drift or lag is less than ±0.1%, and the change of capacity relative to life is less than ±0.1%.

Example 3

Step 1: After cleaning the substrate with acetone, alcohol and deionized water in sequence, perform high-temperature annealing treatment on the substrate. Use the vapor deposition method to grow _SiO2 with a thickness of 500nm on the surface of sapphire as a sacrificial layer, which is used to separate the sapphire substrate from the ceramic film in the later process; continue to use the vapor deposition method to grow a _BaSrTiO3 film with a thickness of 4 μm on the _SiO2 surface, As the dielectric layer of the capacitor;

Step 2: Spin-coat the glass substrate twice with photoresist AZ4620, put it into the temporary bonding machine at the same time as the sapphire substrate with the film grown, apply a pressure of 2 bar and a temperature of 40°C for 30 minutes to complete the temporary bonding of the sapphire substrate , use model No. 0CON-137 SF1 polishing solution to polish the BaSrTiO ₃ film, use polyurethane as the polishing pad material during polishing, the abrasive of the polishing solution is selected from SiO ₂ , the particle size of the abrasive of the polishing solution is 50nm, and the speed of the polishing disc is 70r /min, the quality of the polishing fixture is 5kg, continuous polishing 1.5h obtains a smooth BaTiO ₃ film;

Step 3: Use ultraviolet exposure technology to transfer the pattern to the surface of the BaSrTiO ₃ film, then use magnetron sputtering to grow Au with a thickness of 200 nm on the surface of the developed BaSrTiO ₃ film as the internal pole plate of the capacitor, and then use EVG520 to process the two films Bonding, the temperature during bonding is 230°C, the pressure is 2kN, the bonding time is 8h, and the capacitor unit structure is obtained;

Step 4: use hydrofluoric acid (49wt%) to corrode the SiO ₂ sacrificial layer, release the BaSrTiO ₃ film structure, and sputter electrodes at both ends, repeat steps 1 to 3 to complete the internal capacitance structure of the capacitor, and prepare the multilayer ceramic The film is cut into a size of 0.2cm*0.5cm, and the electrodes at both ends are impregnated with silver paste with a mass fraction of 75wt%. The silver terminal electrode air sintering technology mainly adopts a chain-type terminal electrode sintering furnace with a temperature of 600°C and a time of 60 minutes.

Using an atomic force microscope to test the surface morphology of the polished ceramic film, the measured Ra value is 420pm, and the obtained multilayer ceramic capacitor has a capacitance change rate of 0±35ppm/°C under the condition of -50°C-125°C, and the capacity is at high Under frequency conditions, the rate of change with frequency is less than ±0.2% ΔC, the capacity drift or hysteresis is less than ±0.05%, and the change of capacity relative to life is less than ±0.05%.

Example 4

Step 1: After cleaning the substrate with acetone, alcohol and deionized water in sequence, perform high-temperature annealing treatment on the substrate. Use the vapor deposition method to grow _SiO2 with a thickness of 500nm on the surface of sapphire as a sacrificial layer, which is used to separate the sapphire substrate from the ceramic film in the later process; continue to use the vapor deposition method to grow a _BaTiO3 film with a thickness of 4 μm on the surface of _SiO2 , As the dielectric layer of the capacitor;

Step 2: Spin-coat the glass substrate twice with photoresist AZ4620, put it into the temporary bonding machine at the same time as the sapphire substrate with the film grown, apply a pressure of 2 bar and a temperature of 40°C for 30 minutes to complete the temporary bonding of the sapphire substrate , use model No. 0CON-137 SF1 polishing solution to polish the BaTiO ₃ film, use polyurethane as the polishing pad material during polishing, the abrasive of the polishing solution is selected from SiO ₂ , the particle size of the abrasive of the polishing solution is 50nm, and the speed of the polishing disc is 70r /min, the quality of the polishing fixture is 5kg, continuous polishing 1.5h obtains a smooth BaTiO ₃ film;

Step 3: Use ultraviolet exposure technology to transfer the pattern to the surface of the BaTiO ₃ film, then use magnetron sputtering to grow Pt with a thickness of 200 nm on the surface of the developed BaTiO ₃ film as the internal pole plate of the capacitor, and then use EVG520 to process the two films Bonding, the temperature during bonding is 230°C, the pressure is 2kN, the bonding time is 8h, and the capacitor unit structure is obtained;

Step 4: use hydrofluoric acid (49wt%) to corrode the SiO ₂ sacrificial layer, release the BaTiO ₃ film structure, and sputter electrodes at both ends, repeat steps 1 to 3 to complete the internal capacitance structure of the capacitor, and prepare the multilayer ceramic The film is cut into a size of 0.2cm*0.5cm, and the electrodes at both ends are impregnated with silver paste with a mass fraction of 75wt%. The silver terminal electrode air sintering technology mainly adopts a chain-type terminal electrode sintering furnace with a temperature of 600°C and a time of 60 minutes.

Using an atomic force microscope to test the surface morphology of the polished ceramic film, the measured Ra value is 410pm, and the obtained multilayer ceramic capacitor has a capacitance change rate of 0±25ppm/°C under the condition of -50°C-125°C, and the capacity is at high Under frequency conditions, the rate of change with frequency is less than ±0.3% ΔC, the capacity drift or hysteresis is less than ±0.1%, and the change of capacity relative to life is less than ±0.1%.

Example 5

Step 1: After cleaning the substrate with acetone, alcohol and deionized water in sequence, perform high-temperature annealing treatment on the substrate. Use the vapor deposition method to grow _SiO2 with a thickness of 400nm on the sapphire surface as a sacrificial layer, which is used to separate the sapphire substrate from the ceramic film in the later process; continue to use the vapor deposition method to grow a _BaTiO3 film with a thickness of 2 μm on the _SiO2 surface, As the dielectric layer of the capacitor;

Step 2: Spin-coat the glass substrate twice with photoresist AZ4620, put it into the temporary bonding machine at the same time as the sapphire substrate with the film grown, apply a pressure of 2 bar and a temperature of 40°C for 30 minutes to complete the temporary bonding of the sapphire substrate , use model No. 0CON-137 SF1 polishing solution to polish the BaTiO ₃ film, use polyurethane as the polishing pad material during polishing, the abrasive of the polishing solution is selected from SiO ₂ , the particle size of the abrasive of the polishing solution is 40nm, and the rotational speed of the polishing disc is 50r /min, the quality of the polishing fixture is 5kg, continuous polishing 1.5h obtains a smooth BaTiO ₃ film;

Step 3: Use ultraviolet exposure technology to transfer the pattern to the surface of the BaTiO ₃ film, then use magnetron sputtering to grow Au with a thickness of 100 nm on the surface of the developed BaTiO ₃ film as the internal pole plate of the capacitor, and then use EVG520 to process the two films Bonding, the bonding temperature is 200°C, the pressure is 1kN, the bonding time is 6h, and the capacitor unit structure is obtained;

Step 4: use hydrofluoric acid (49wt%) to corrode the SiO ₂ sacrificial layer, release the BaTiO ₃ film structure, and sputter electrodes at both ends, repeat steps 1 to 3 to complete the internal capacitance structure of the capacitor, and prepare the multilayer ceramic The film is cut into a size of 0.2cm*0.5cm, and the electrodes at both ends are impregnated with silver paste with a mass fraction of 70wt%. The silver terminal electrode air sintering technology mainly adopts a chain-type terminal electrode sintering furnace with a temperature of 500°C and a time of 70 minutes.

Using an atomic force microscope to test the surface morphology of the polished ceramic film, the measured Ra value is 428pm, and the capacitance change rate of the obtained multilayer ceramic capacitor is 0±20ppm/°C under the condition of -50°C-125°C, and the capacity is at high Under frequency conditions, the rate of change with frequency is less than ±0.5% ΔC, the capacity drift or hysteresis is less than ±0.05%, and the change of capacity relative to life is less than ±0.05%.

Example 6

Step 1: After cleaning the substrate with acetone, alcohol and deionized water in sequence, perform high-temperature annealing treatment on the substrate. Use the vapor deposition method to grow _SiO2 with a thickness of 600nm on the surface of sapphire as a sacrificial layer, which is used to separate the sapphire substrate from the ceramic film in the later process; continue to use the vapor deposition method to grow a _BaTiO3 film with a thickness of 5 μm on the surface of _SiO2 , As the dielectric layer of the capacitor;

Step 2: Spin-coat the glass substrate twice with photoresist AZ4620, put it into the temporary bonding machine at the same time as the sapphire substrate with the film grown, apply a pressure of 2 bar and a temperature of 40°C for 30 minutes to complete the temporary bonding of the sapphire substrate , use model No. 0CON-137 SF1 polishing solution to polish the BaTiO ₃ film, use polyurethane as the polishing pad material during polishing, the abrasive of the polishing solution is selected from SiO ₂ , the particle size of the abrasive of the polishing solution is 60nm, and the speed of the polishing disc is 80r /min, the quality of the polishing fixture is 5kg, continuous polishing 1.5h obtains a smooth BaTiO ₃ film;

Step 3: Use ultraviolet exposure technology to transfer the pattern to the surface of the BaTiO ₃ film, then use magnetron sputtering to grow Au with a thickness of 300 nm on the surface of the developed BaTiO ₃ film as the internal pole plate of the capacitor, and then use EVG520 to process the two films Bonding, the temperature during bonding is 250°C, the pressure is 3kN, the bonding time is 10h, and the capacitor unit structure is obtained;

Step 4: use hydrofluoric acid (49wt%) to corrode the SiO ₂ sacrificial layer, release the BaTiO ₃ film structure, and sputter electrodes at both ends, repeat steps 1 to 3 to complete the internal capacitance structure of the capacitor, and prepare the multilayer ceramic The film is cut into a size of 0.2cm*0.5cm, and the electrodes at both ends are impregnated with silver paste with a mass fraction of 90wt%. The silver terminal electrode air sintering technology mainly adopts a chain-type terminal electrode sintering furnace with a temperature of 800°C and a time of 80 minutes.

Using an atomic force microscope to test the surface morphology of the polished ceramic film, the measured Ra value is 414pm, and the capacitance change rate of the obtained multilayer ceramic capacitor is 0±36ppm/°C under the condition of -50°C-125°C, and the capacity is at high Under frequency conditions, the rate of change with frequency is less than ±0.3% ΔC, the capacity drift or hysteresis is less than ±0.05%, and the change of capacity relative to life is less than ±0.1%.

In summary, the present application grows a _SiO2 sacrificial layer and a ceramic thin film layer on the substrate, carries out chemical mechanical polishing and sputtering electrodes on the ceramic thin film layer respectively, bonds the two ceramic thin film layers, and then corrodes the _SiO2 sacrificial layer releasing the ceramic thin film layer, sputtering electrodes at both ends of the released ceramic thin film layer, and finally impregnating the electrodes at both ends of the ceramic thin film layer and calcining at high temperature to obtain a multilayer ceramic capacitor.

The preparation method of the multilayer ceramic capacitor based on chemical mechanical polishing of the present application combines the method of chemical mechanical polishing and indirect bonding to realize the manufacture of multilayer ceramic capacitors, and uses the method of chemical mechanical polishing to replace the conventional casting method, avoiding the The temperature control in the tape casting process can realize the preparation of ceramic films at room temperature, reducing the adverse effects of high temperature, cooling and drying processes on film quality and performance. No high-temperature sintering process is required, and the operating temperature is lower, which ensures the yield of ceramic thin films.

The multilayer ceramic capacitor based on chemical mechanical polishing of the present application has the characteristics of high quality, low stress and high density, and realizes device preparation with high flatness, high performance and high yield.

As mentioned above, the above embodiments are only used to illustrate the technical solutions of the present application, and are not intended to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: it can still understand the foregoing The technical solutions described in each embodiment are modified, or some of the technical features are equivalently replaced; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the various embodiments of the application.

Claims (8)

1. A method for preparing a multilayer ceramic capacitor based on chemical mechanical polishing, comprising the steps of: Clean the substrate, and grow _SiO2 sacrificial layer and ceramic thin film layer on the substrate in turn; Carry out chemical mechanical polishing and sputtering electrodes on the ceramic thin film layers respectively, and bond the two ceramic thin film layers; Etching the _SiO sacrificial layer to release the ceramic film layer, and sputtering electrodes at both ends of the released ceramic film layer; The two ends of the ceramic film layer after the sputtering electrode are repeatedly bonded; The electrodes at both ends of the ceramic film layer are impregnated and calcined at high temperature to obtain a multilayer ceramic capacitor; Using the vapor deposition growth method, the thickness of the SiO ₂ sacrificial layer is 400~600nm, and the thickness of the ceramic film layer is 2~5μm; The bonding temperature of the ceramic film layer is 200~250°C, the pressure is 1~3kN, and the bonding time is 6~10h; Wherein, the two ends of the ceramic film layer after sputtering the electrodes are repeatedly bonded, specifically: use hydrofluoric acid to corrode the SiO2 sacrificial layer, release the BaTiO3 film structure, and sputter the electrodes at both ends, repeat the above steps To complete the internal capacitance structure of the capacitor, cut the prepared multilayer ceramic film into a size of 0.2cm*0.5cm, and impregnate the electrodes at both ends with silver paste. 2. The preparation method of multilayer ceramic capacitor according to claim 1, wherein the substrate is a sapphire substrate, the material of the ceramic film is selected from CaSrZrO ₃ , BaTiO ₃ or BaSrTiO ₃ , and the material of the electrode is selected from Au or Pt. 3. the preparation method of multilayer ceramic capacitor according to claim 1, is characterized in that, cleaning substrate is specifically: After cleaning the substrate with acetone, alcohol and deionized water in sequence, the substrate is subjected to high-temperature annealing treatment. 4. the preparation method of multilayer ceramic capacitor according to claim 1 is characterized in that, the polishing pad material used in the chemical mechanical polishing is polyurethane, and the polishing liquid abrasive is selected from SiO ₂ , and the particle size of the polishing liquid abrasive is 40 ~60nm, the speed of the polishing disc is 50~80r/min. 5. The method for preparing a multilayer ceramic capacitor according to claim 1, wherein the sputtering electrode uses a magnetron sputtering method, and the thickness of the sputtering electrode is 100-300nm. 6. the preparation method of multilayer ceramic capacitor according to claim 1, is characterized in that, the impregnating liquid that impregnates both ends electrode is the silver paste that massfraction is 70～90wt%; The temperature of the high-temperature calcination is 500-800° C., and the time is 60-80 minutes. 7. A multilayer ceramic capacitor based on chemical mechanical polishing, characterized in that it is prepared by the preparation method described in any one of claims 1-6. 8. The multilayer ceramic capacitor according to claim 7, characterized in that the diameter of the ceramic film layer is greater than or equal to 5 cm, the thickness is less than or equal to 5 μm, and the thickness of the sputtered metal electrode is greater than or equal to 100 nm.

Images