Ceramic substrate, low-temperature co-fired ceramic device and preparation method thereof

Abstract

The invention discloses a ceramic substrate, a low-temperature co-fired ceramic device and a preparation method of the low-temperature co-fired ceramic device, and belongs to the technical field of low-temperature co-fired ceramics. The ceramic substrate comprises a first ceramic dielectric layer and a first electrode layer; one side of the first ceramic dielectric layer is provided with a slotted hole, and the slotted hole is filled with a first auxiliary electrode; the first electrode layer is arranged on one side, provided with the slotted hole, of the first ceramic dielectric layer; the first electrode layer comprises a first electrode, and the first electrode is connected with the first auxiliary electrode. According to the embodiment of the invention, the adhesive force of the electrode in the ceramic substrate can be improved, and the reliability of a low-temperature co-fired ceramic device can be improved.

Description

Technical Field

[0001] The invention relates to the technical field of low temperature co-fired ceramics, and in particular to a ceramic substrate, a low temperature co-fired ceramic device and a preparation method thereof. Background Art

[0002] The reliability of low temperature cofired ceramic (LTCC) devices is strongly related to the adhesion between the ceramic dielectric layer and the electrode layer, especially the adhesion between the device's external electrode and its ceramic dielectric layer. At present, there are many types of dielectric ceramics for LTCC devices. In related technologies, in order to improve the adhesion, priority is usually given to adding different inorganic substances to the silver paste formula from the perspective of silver-ceramic matching, and experimenting with a combination suitable for specific ceramic materials from a variety of inorganic substances. However, it takes a long time to find a material combination, and a lot of repetitive work needs to be done for different ceramic materials. In addition, under the existing material combination, it is difficult to achieve a major breakthrough in the electrode adhesion of LTCC devices under silver-ceramic co-firing. Especially for electronic components for automotive needs, their application scenarios are more demanding than consumer electronic components, reliability issues are more important, and the requirements for electrode adhesion are higher. Summary of the invention

[0003] The present invention provides a ceramic substrate, a low-temperature co-fired ceramic device and a preparation method thereof, so as to improve the adhesion of electrodes in the ceramic substrate, which is beneficial to improving the reliability of the low-temperature co-fired ceramic device.

[0004] In a first aspect, an embodiment of the present invention provides a ceramic substrate, comprising:

[0005] A first ceramic dielectric layer; a slot is formed on one side of the first ceramic dielectric layer, and a first auxiliary electrode is filled in the slot;

[0006] The first electrode layer is arranged on one side of the first ceramic dielectric layer where the slot is opened; the first electrode layer includes a first electrode, and the first electrode is connected to the first auxiliary electrode.

[0007] Optionally, the slot is a circular hole, an elliptical hole or a square hole;

[0008] Alternatively, the opening area of ​​the slot gradually increases in a direction away from the first electrode layer.

[0009] Optionally, the adhesion between the first auxiliary electrode and the first ceramic dielectric layer is greater than or equal to the adhesion between the first electrode and the first ceramic dielectric layer;

[0010] and / or,

[0011] The adhesion between the first electrode and the first auxiliary electrode is greater than the adhesion between the first electrode and the first ceramic dielectric layer.

[0012] Optionally, the first auxiliary electrode and the first electrode are made of the same material;

[0013] And / or, the first electrode covers a surface of the first auxiliary electrode close to the first electrode layer, and a vertical projection area of ​​the first electrode on the first ceramic dielectric layer is larger than an area of ​​a surface of the first auxiliary electrode close to the first electrode layer.

[0014] In a second aspect, an embodiment of the present invention further provides a low temperature co-fired ceramic device, comprising: a ceramic substrate provided by any embodiment of the present invention, and at least one inner electrode substrate stacked with the ceramic substrate;

[0015] Wherein, the first electrode in the ceramic substrate serves as an external electrode exposed on the surface of the low-temperature co-fired ceramic device;

[0016] Each of the inner electrode substrates includes a second ceramic dielectric layer; at least one of the inner electrode substrates includes a second electrode layer, and the second electrode layer is arranged on a side of the second ceramic dielectric layer in the inner electrode substrate close to the ceramic substrate.

[0017] Optionally, the inner electrode substrate adjacent to the ceramic substrate includes the second electrode layer;

[0018] In the inner electrode substrate adjacent to the ceramic substrate, the second electrode layer includes: a second auxiliary electrode; the slot and the first auxiliary electrode both penetrate the first ceramic dielectric layer; the second auxiliary electrode is connected to a side of the first auxiliary electrode away from the first electrode;

[0019] The area of ​​the vertical projection of the second auxiliary electrode on the first ceramic dielectric layer is larger than the area of ​​the surface of the first auxiliary electrode away from the first electrode layer.

[0020] Optionally, at least part of the membrane layers in the first ceramic dielectric layer and each of the second ceramic dielectric layers further include structural holes penetrating the membrane layers, and the structural holes are filled with via electrodes; wherein, in the first electrode layer and each of the second electrode layers, different layers are connected through the via electrodes.

[0021] In a third aspect, an embodiment of the present invention further provides a method for preparing a low-temperature co-fired ceramic device, which is used to prepare the low-temperature co-fired ceramic device provided by any embodiment of the present invention;

[0022] The method for preparing the low temperature co-fired ceramic device comprises:

[0023] A ceramic substrate and at least one inner electrode substrate are provided; wherein the ceramic substrate comprises a first ceramic dielectric layer and a first electrode layer which are stacked; a slot is provided on one side of the first ceramic dielectric layer, and a first auxiliary electrode is filled in the slot; the first electrode layer is provided on the side of the first ceramic dielectric layer where the slot is provided; the first electrode layer comprises a first electrode, and the first electrode is connected to the first auxiliary electrode; each of the inner electrode substrates comprises a second ceramic dielectric layer, and at least one of the inner electrode substrates comprises a second electrode layer provided on one side of the second ceramic dielectric layer; the ceramic substrate and each of the inner electrode substrates comprise positioning holes;

[0024] Based on each of the positioning holes, the ceramic substrate and each of the internal electrode substrates are laminated and pressed to obtain a laminated structure; wherein the first electrode layer is exposed on the surface of the laminated structure; in the laminated structure, the second electrode layer is located on the side of the second ceramic dielectric layer in the internal electrode substrate close to the ceramic substrate.

[0025] Optionally, providing the ceramic substrate includes:

[0026] Providing the first ceramic dielectric layer, and preparing the positioning holes, the slot holes and the structural holes on the first ceramic dielectric layer;

[0027] Filling the slot to form the first auxiliary electrode; and filling the structural hole to form a via electrode;

[0028] The first electrode layer is prepared on one side of the first ceramic dielectric layer where the slot is opened;

[0029] Providing the inner electrode substrate includes:

[0030] Providing the second ceramic dielectric layer, and preparing the positioning holes and the structural holes on the second ceramic dielectric layer;

[0031] Filling the structural hole to form a via electrode;

[0032] For the inner electrode substrate including the second electrode layer, after the structural hole is filled to form the via electrode, the method further comprises: preparing the second electrode layer on one side of the second ceramic dielectric layer;

[0033] Wherein, in the stacked structure, different layers in the first electrode layer and each of the second electrode layers are connected through the via electrodes.

[0034] Optionally, after obtaining the laminated structure, the method further comprises:

[0035] Cutting the stacked structure to obtain a device substrate;

[0036] Debinding the device substrate;

[0037] The device substrate after debinding is sintered to obtain a low temperature co-fired ceramic device.

[0038] In the ceramic substrate provided by the embodiment of the present invention, a first auxiliary electrode embedded in the first ceramic dielectric layer is provided, and the first electrode is connected to the first auxiliary electrode to form an integral electrode structure. Compared with the solution in which the first electrode only contacts the surface of the first ceramic dielectric layer, the integral electrode structure formed by the first auxiliary electrode and the first electrode has a larger contact area with the first ceramic dielectric layer, and the friction force and structural force between the first auxiliary electrode and the ceramic body in the first ceramic dielectric layer can effectively increase the adhesion of the first electrode on the first ceramic dielectric layer. Therefore, the embodiment of the present invention can improve the adhesion of the electrode in the ceramic substrate, which is conducive to improving the reliability of the low-temperature co-fired ceramic device containing the ceramic substrate.

[0039] It should be understood that the contents described in this section are not intended to identify the key or important features of the embodiments of the present invention, nor are they intended to limit the scope of the present invention. Other features of the present invention will become easily understood through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0041] Figure 1 is a structural schematic diagram of a ceramic substrate provided by an embodiment of the present invention;

[0042] Figure 2 is a schematic structural diagram of another ceramic substrate provided by an embodiment of the present invention;

[0043] Figure 3 is a structural schematic diagram of another ceramic substrate provided by an embodiment of the present invention;

[0044] Figure 4 is a schematic structural diagram of a low-temperature co-fired ceramic device provided by an embodiment of the present invention;

[0045] Figure 5 is a schematic structural diagram of another low-temperature co-fired ceramic device provided by an embodiment of the present invention;

[0046] Figure 6 is a schematic structural diagram of another low-temperature co-fired ceramic device provided by an embodiment of the present invention;

[0047] Figure 7 is a device electrical property comparison diagram before and after adding a first auxiliary electrode provided by an embodiment of the present invention;

[0048] Figure 8 It is a schematic flow chart of a method for preparing a low-temperature co-fired ceramic device provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0049] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0050] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the numbers used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions.

[0051] The embodiment of the present invention provides a ceramic substrate, which can effectively improve the adhesion between an electrode and a ceramic dielectric layer. Figure 1 Schematic diagram of the structure of a ceramic substrate provided by an embodiment of the present invention. Figure 1 The ceramic substrate includes: a first ceramic dielectric layer 11 and a first electrode layer which are stacked. A slot is provided on one side of the first ceramic dielectric layer 11, and a first auxiliary electrode 131 is filled in the slot. The first electrode layer is provided on the side of the first ceramic dielectric layer 11 where the slot is provided; the first electrode layer includes a first electrode 121, and the first electrode 121 is connected to the first auxiliary electrode 131.

[0052] The first ceramic dielectric layer 11 may have at least one slot, each of which is filled with a first auxiliary electrode 131. The first electrode layer includes at least one first electrode 121. One first electrode 121 is connected to at least one first auxiliary electrode 131. Figure 1As an example, the first electrode 121 and the first auxiliary electrode 131 are arranged in a one-to-one correspondence, but this is not intended to limit the present invention. When the adhesion requirement is high, a first electrode 121 can be provided to connect multiple first auxiliary electrodes 131. It is understandable that the number of first electrodes 121 can be set according to the design requirements of the low-temperature co-fired ceramic device. The ceramic substrate can be used as any layer of the ceramic substrate in the low-temperature co-fired ceramic device, for example, it can be used as the outermost ceramic substrate in the low-temperature co-fired ceramic device, and the first electrode 121 can be used as an external electrode of the low-temperature co-fired ceramic device, for example, as a bottom electrode or a top electrode.

[0053] In the ceramic substrate provided by the embodiment of the present invention, a first auxiliary electrode 131 embedded in the first ceramic dielectric layer 11 is provided, and the first electrode 121 is connected to the first auxiliary electrode 131 to form an integral electrode structure. Compared with the solution in which the first electrode 121 only contacts the surface of the first ceramic dielectric layer 11, the integral electrode structure formed by the first auxiliary electrode 131 and the first electrode 121 has a larger contact area with the first ceramic dielectric layer 11, and the friction force and structural force between the first auxiliary electrode 131 and the ceramic body in the first ceramic dielectric layer 11 can effectively increase the adhesion of the first electrode 121 on the first ceramic dielectric layer 11. Therefore, the embodiment of the present invention can improve the adhesion of the electrode in the ceramic substrate, which is conducive to improving the reliability of the low-temperature co-fired ceramic device including the ceramic substrate.

[0054] Based on the above embodiments, optionally, the first auxiliary electrode 131 fills the entire slot, and the shape of the first auxiliary electrode 131 finally formed is determined according to the shape of the slot. There are many ways to set the slot, and several of them are exemplarily described below.

[0055] For slot depth: In one embodiment, optionally, see Figure 1 , the depth of the slot may be less than the depth of the first ceramic dielectric layer 11. In another embodiment, optionally, see Figure 2 The depth of the slot may be equal to the depth of the first ceramic dielectric layer 11 , that is, the slot and the first auxiliary electrode 131 may both penetrate the first ceramic dielectric layer 11 .

[0056] Regarding the shape of the slot hole: the slot hole can be a circular hole, an elliptical hole or a square hole. In the thickness direction of the first ceramic dielectric layer 11, the opening area of ​​the slot hole at different positions can be kept consistent. Or, Figure 3 As shown, in the direction away from the first electrode layer (eg Figure 3 The opening area of ​​the slot gradually increases, so that the first auxiliary electrode 131 is not easy to escape from the slot, and the adhesion of the first electrode 121 is further increased.

[0057] It is understandable that when the first ceramic dielectric layer 11 includes multiple slots, the sizes, shapes and depths of the multiple slots can be set according to the design requirements of adhesion, and any of the sizes, shapes and depths of different slots can be the same or different.

[0058] On the basis of the above embodiments, optionally, the first electrode 121 covers the surface of the first auxiliary electrode 131 close to the first electrode layer to ensure that the contact area between the first electrode 121 and the first auxiliary electrode 131 is sufficient to prevent the first electrode 121 from being separated from the first auxiliary electrode 131. It is also possible to set the vertical projection area of ​​the first electrode 121 on the first ceramic dielectric layer 11 to be larger than the surface area of ​​the first auxiliary electrode 131 close to the first electrode layer, so that a part of the surface of the first electrode 121 close to the first auxiliary electrode 131 is in contact with the first auxiliary electrode 131, and the remaining area is in contact with the first ceramic dielectric layer 11. Exemplarily, the first auxiliary electrode 131 can be connected to any position of the first electrode 121, such as the center position or the edge position, and can be specifically designed according to actual needs.

[0059] On the basis of the above embodiments, optionally, the selection of the material of the first auxiliary electrode 131 may satisfy the following conditions: the adhesion between the first auxiliary electrode 131 and the first ceramic dielectric layer 11 is greater than or equal to the adhesion between the first electrode 121 and the first ceramic dielectric layer 11. That is, the first auxiliary electrode 131 is prepared by using a material whose adhesion to ceramic is not less than that of the first electrode 121, which can effectively ensure the adhesion of the combination of the first auxiliary electrode 131 and the first electrode 121 to the ceramic.

[0060] The adhesion between the first electrode 121 and the first auxiliary electrode 131 can also be set to be greater than the adhesion between the first electrode 121 and the first ceramic dielectric layer 11, so that the first electrode 121 and the first auxiliary electrode 131 are not easily separated, thereby utilizing the adhesion between the first auxiliary electrode 131 and the ceramic to increase the adhesion of the first electrode 121 and prevent the first electrode 121 from separating from the first ceramic dielectric layer 11.

[0061] Based on the above embodiments, optionally, the first electrode 121 and the first auxiliary electrode 131 can be made of metal materials. Exemplarily, the first electrode 121 and the first auxiliary electrode 131 can be made of the same material to form a better internal bonding force, and the specific material is, for example, silver.

[0062] In summary, in the embodiment of the present invention, the first auxiliary electrode 131 is provided to form a wedge structure embedded in the first ceramic dielectric layer 11, and the first electrode 121 is connected to the wedge structure to form an integral structure. The internal friction between the wedge structure and the ceramic body in the first ceramic dielectric layer 11 can improve the adhesion of the first electrode 121 on the first ceramic dielectric layer 11.

[0063] An embodiment of the present invention further provides a low-temperature co-fired ceramic device, including the ceramic substrate provided by any embodiment of the present invention, and having corresponding beneficial effects.

[0064] Figure 4 Schematic diagram of the structure of a low temperature co-fired ceramic device provided by an embodiment of the present invention. Figure 4 , the low-temperature co-fired ceramic device may include: a ceramic substrate, and at least one inner electrode substrate stacked with the ceramic substrate. Among them, the first electrode 121 in the ceramic substrate serves as an external electrode exposed to the surface of the low-temperature co-fired ceramic device. Each inner electrode substrate includes a second ceramic dielectric layer 21; at least one inner electrode substrate includes a second electrode layer, and the second electrode layer may include at least one inner electrode 222 for forming a functional circuit inside the low-temperature co-fired ceramic device. Exemplarily, the low-temperature co-fired ceramic device can be a filter, and each inner electrode 222, or each inner electrode 222 in combination with the first electrode 121, can be used to form devices such as capacitors and inductors in the filter. Among them, the patterns of the above-mentioned electrodes can be set according to actual needs, and are not specifically limited here.

[0065] In the stacked structure, the second electrode layer is arranged on the side of the second ceramic dielectric layer in the inner electrode substrate close to the ceramic substrate. That is, when the ceramic substrate and each inner electrode substrate are stacked, the electrode layers in the substrate are all stacked on one side of the ceramic dielectric layer. Figure 4 As shown, in the low temperature co-fired ceramic device, the first electrode layer is located below the first ceramic dielectric layer; in the inner electrode substrate provided with the second electrode layer, the second electrode layer is located below the second ceramic dielectric layer. In this way, there can be at most one electrode layer between two adjacent ceramic dielectric layers, avoiding direct contact between different electrode layers and causing unnecessary short circuits between electrodes.

[0066] Exemplarily, the first ceramic dielectric layer 11 and the second ceramic dielectric layer 21 can be made of the same material, for example, both are glass ceramics. The thickness of the first ceramic dielectric layer 11 and the second ceramic dielectric layer 21 can be between 20 μm and 50 μm. The first electrode 121 and the internal electrode 222 can be made of the same material, for example, both are metal materials, specifically silver. The thickness of the first electrode layer and the second electrode layer can be between 4 μm and 12 μm, and further can be between 9 μm and 11 μm. For the convenience of explanation below, when it is necessary to uniformly describe the characteristics of the first ceramic dielectric layer 11 and the second ceramic dielectric layer 21, the first ceramic dielectric layer 11 and the second ceramic dielectric layer 21 are collectively referred to as ceramic dielectric layers; similarly, when necessary, the first electrode layer and the second electrode layer are collectively referred to as electrode layers, and the first electrode 121 and the internal electrode 222 are collectively referred to as electrodes.

[0067] In the low-temperature co-fired ceramic device, there are ceramic dielectric layers on both sides of each inner electrode 222. The ceramic dielectric layers on both sides of the inner electrode 222 can be sintered into a solid integral structure and wrap the inner electrode 222 to limit the inner electrode 222, so that the inner electrode 222 is not prone to the risk of peeling off from the ceramic dielectric layer. Compared with the inner electrode 222, only one side of the outer electrode is in contact with the ceramic dielectric layer, and the other side is directly exposed to the outside, and the risk of peeling off the outer electrode is greater. In the embodiment of the present invention, the ceramic substrate is used as the outer substrate in the low-temperature co-fired ceramic device, and the first electrode 121 is used as the outer electrode in the low-temperature co-fired ceramic device, which can effectively increase the adhesion of the outer electrode in the low-temperature co-fired ceramic device, thereby improving the reliability of the device.

[0068] On the basis of the above embodiments, optionally, at least part of the film layers in the first ceramic dielectric layer 11 and each second ceramic dielectric layer 21 further include structural holes penetrating the film layers, and the structural holes are filled with via electrodes 23. Among them, in the first electrode layer and each second electrode layer, different electrode layers are connected through via electrodes 23. The structural holes and the slots are arranged at intervals, so that the via electrodes 23 are insulated from the first auxiliary electrode 131 to avoid affecting the electrical properties of the device.

[0069] Specifically, the internal electrodes 222 of different layers can be connected through the via electrodes 23, and the first electrode 121 can be connected to the internal electrode 222 in any layer through the via electrodes 23. When there are multiple ceramic dielectric layers between two layers of electrodes to be connected, structural holes can be set in the multiple ceramic dielectric layers and filled with via electrodes 23, and the via electrodes 23 in the multiple ceramic dielectric layers are aligned and connected as a whole to connect the two layers of electrodes.

[0070] Figure 5 Schematic diagram of another low temperature co-fired ceramic device provided by an embodiment of the present invention. Figure 5On the basis of the above embodiments, optionally, the inner electrode substrate adjacent to the ceramic substrate includes a second electrode layer. In the inner electrode substrate adjacent to the ceramic substrate, the second electrode layer includes: a second auxiliary electrode 221; the slot and the first auxiliary electrode 131 both penetrate the first ceramic dielectric layer 11; the second auxiliary electrode 221 is connected to the side of the first auxiliary electrode 131 away from the first electrode 121. In the vertical projection area of ​​the second auxiliary electrode 221 on the first ceramic dielectric layer 11 is larger than the surface area of ​​the first auxiliary electrode 131 away from the first electrode layer.

[0071] The second auxiliary electrode 221 is provided in this embodiment, which is equivalent to providing an auxiliary component parallel to the first electrode 121 inside the low-temperature co-fired ceramic device. The second auxiliary electrode 221, the first auxiliary electrode 131 and the first electrode 121 are connected as an integral structure. The second auxiliary electrode 221 embedded between the first ceramic dielectric layer 11 and the adjacent second ceramic dielectric layer 21 can be used to firmly grasp the inside of the device, further improve the adhesion of the first electrode 121 on the low-temperature co-fired ceramic device, and prevent the first electrode 121 from peeling off. It can be understood that the second electrode layer of the inner electrode substrate adjacent to the ceramic substrate can also include an inner electrode 222, and the inner electrode 222 is insulated from the second auxiliary electrode 221. The second auxiliary electrode 221 can be arranged away from the required position of the inner electrode 222 in the device to avoid affecting the electrical properties of the device.

[0072] On the basis of the above embodiments, optionally, the second auxiliary electrode 221 may be arranged to completely cover the surface of the first auxiliary electrode 131 away from the first electrode 121, so as to ensure that the contact area between the second auxiliary electrode 221 and the first auxiliary electrode 131 is sufficient to avoid separation between the two. Exemplarily, one second auxiliary electrode 221 may be connected to at least part of the first auxiliary electrode 131 connected to the same first electrode 121. Exemplarily, the cross-sectional shape of the structure obtained by connecting the second auxiliary electrode 221 to the first auxiliary electrode 131 may be L-shaped or T-shaped.

[0073] On the basis of the above embodiments, optionally, the first auxiliary electrode 131 and the second auxiliary electrode 221 can be made of the same material to form a better internal bonding force. For example, a metal material, specifically silver, is used. Exemplarily, each first electrode 121, each inner electrode 222, each first auxiliary electrode 131 and each second auxiliary electrode 221 can be made of the same material to simplify the device manufacturing process.

[0074] In a specific embodiment, the low temperature co-fired ceramic device can be a filter, and the structure diagram of the filter can be seen in Figure 6, wherein the first electrode 121 is used as the bottom electrode; the device is embedded with a plurality of square first auxiliary electrodes 131, which are respectively connected to the plurality of first electrodes 121; the internal electrodes 222 inside the device are represented by a semi-transparent pattern, and the internal electrodes 222 of each layer are used to form the inductance and capacitance of the filter; the internal electrodes 222 and the first electrodes 121 that require electrical connection, as well as the internal electrodes of different layers, are connected by via electrodes 23. Exemplarily, the filter is a rectangular parallelepiped, and the dimensions are, for example, length×width×height=(1.6±0.15)×(0.8±0.15)×(0.6±0.1)mm.

[0075] In order to verify the adhesion of the external electrodes of the low temperature co-fired ceramic device provided by the embodiment of the present invention, the inventors Figure 6 The structure in FIG. 1 is compared with the original structure without the first auxiliary electrode 131. According to the comparison results, by embedding the first auxiliary electrode 131, the adhesion force can be increased from the original 8N to 14N. In addition, the inventors also simulated the electrical properties of the device before and after adding the first auxiliary electrode. The comparison results can be seen in Figure 7 . Figure 7 In the figure, the solid line represents the electrical properties of the original device without the first auxiliary electrode 131, and the dotted line represents Figure 6 The electrical properties of the device having the first auxiliary electrode 131 are shown in the figure; the horizontal axis represents the frequency, and the vertical axis represents the S parameter. The figure shows S(2,1), i.e., the curve of the forward transmission gain, and S(2,2), i.e., the curve of the output return loss. Figure 7 It can be seen that the provision of the first auxiliary electrode 131 has almost no effect on the electrical properties of the product, indicating that the device structure provided by the embodiment of the present invention can effectively improve the adhesion of the external electrode without affecting the electrical properties of the device.

[0076] An embodiment of the present invention further provides a method for preparing a low-temperature co-fired ceramic device, which is used to prepare the low-temperature co-fired ceramic device provided by any embodiment of the present invention and has corresponding beneficial effects. Figure 8 Schematic diagram of a method for preparing a low temperature co-fired ceramic device provided by an embodiment of the present invention. Figure 8 , the preparation method of the low temperature co-fired ceramic device comprises:

[0077] S110, providing a ceramic substrate and at least one inner electrode substrate.

[0078] Among them, the ceramic substrate includes a first ceramic dielectric layer and a first electrode layer stacked in layers; a slot is provided on one side of the first ceramic dielectric layer, and a first auxiliary electrode is filled in the slot; the first electrode layer is provided on the side of the first ceramic dielectric layer where the slot is provided; the first electrode layer includes a first electrode, and the first electrode is connected to the first auxiliary electrode; each inner electrode substrate includes a second ceramic dielectric layer, and at least one inner electrode substrate includes a second electrode layer provided on one side of the second ceramic dielectric layer; the ceramic substrate and each inner electrode substrate include positioning holes. The structures of the ceramic substrate and the inner electrode substrate can refer to the specific descriptions in the above embodiments, and will not be repeated here. Among them, the positioning holes are provided to facilitate accurate alignment between the ceramic dielectric layers when the substrates are stacked.

[0079] S120 , laminating and pressing the ceramic substrate and the internal electrode substrates based on the positioning holes to obtain a laminated structure.

[0080] The first electrode layer is exposed on the surface of the laminated structure; in the laminated structure, the second electrode layer is located on the side of the second ceramic dielectric layer in the inner electrode substrate close to the ceramic substrate. When laminating, each substrate can be arranged and stacked in sequence according to the stacking order in the design. For example, after the substrates are stacked, they can be tightly combined by hot pressing.

[0081] Based on the above embodiments, optionally, providing a ceramic substrate includes the following steps:

[0082] 1) Providing a first ceramic dielectric layer, and preparing positioning holes, slot holes and structural holes on the first ceramic dielectric layer.

[0083] The first ceramic dielectric layer can be a glass ceramic substrate with a thickness of 20 to 50 μm formed by tape casting, which can also be called an external electrode green tape layer. The positioning holes, slot holes and structural holes can all be formed by laser drilling. The positioning holes can be set around the first ceramic dielectric layer for subsequent cutting. The positioning holes can be used for lamination alignment and printing alignment.

[0084] 2) Filling the slot to form a first auxiliary electrode; and filling the structural hole to form a via electrode.

[0085] The first ceramic dielectric layer with structural holes / slots can be filled with electrode slurry through a printed screen; then the electrode slurry is dried at a preset temperature for a preset time to solidify into an electrode. The preset temperature is, for example, 50 to 65°C, and the preset time is, for example, 3 to 10 minutes, specifically 5 minutes. The greater the hole depth, the longer the drying time can be set. The electrode slurry is, for example, silver paste.

[0086] 3) A first electrode layer is prepared on the side of the first ceramic dielectric layer where the slot is formed.

[0087] The first electrodes can be printed on one side of the first ceramic dielectric layer by screen printing combined with drying process, and the first electrodes can be combined with the electrode paste filled in the slots. The electrode paste for printing the first electrodes can be silver paste, with a printing thickness of 9 to 11 μm, and then placed at a temperature of 50 to 65° C. for drying for 5 minutes.

[0088] Based on the above embodiments, optionally, providing an inner electrode substrate includes:

[0089] 1) providing a second ceramic dielectric layer, and preparing positioning holes and structural holes on the second ceramic dielectric layer;

[0090] The relevant preparation process of the second ceramic dielectric layer can refer to the preparation process of the first ceramic dielectric layer, which will not be described in detail here. The second ceramic dielectric layer can also be called an inner electrode green tape layer.

[0091] 2) Fill the structural holes to form via electrodes.

[0092] For the inner electrode substrate including the second electrode layer, after filling the structural hole to form the via electrode, the method further comprises: preparing the second electrode layer on one side of the second ceramic dielectric layer.

[0093] The relevant preparation process of the second electrode layer can refer to the preparation process of the first electrode layer, which will not be repeated here. It is understandable that when a second auxiliary electrode is required in a low-temperature co-fired ceramic device, the second auxiliary electrode can be prepared at the same time as the internal electrode is prepared in the corresponding second electrode layer.

[0094] Wherein, in the laminated structure, the first electrode layer and different layers in each second electrode layer are connected through via electrodes, and there is at most one second electrode layer between every two adjacent ceramic dielectric layers.

[0095] Based on the above embodiments, optionally, after obtaining the laminated structure, the method further includes:

[0096] The stacked structure is cut to obtain a device substrate.

[0097] The device substrate is a substrate of a single low-temperature co-fired ceramic device that meets the preset size. Exemplarily, in this step, redundant parts such as positioning holes that are required for the preparation process but not required for the device can be removed.

[0098] Debonding the device substrate.

[0099] Among them, in the device substrate obtained by cutting, there are organic substances such as adhesives and dispersants between at least part of the film layers. This step can decompose and volatilize the organic substances at a certain temperature.

[0100] The device substrate after debinding is sintered to obtain a low temperature co-fired ceramic device.

[0101] This step is to crystallize the ceramic inorganic material left after debinding. By co-firing at low temperature, a complete and dense ceramic body can be formed. One side of the first auxiliary electrode contacts the external electrode, and they fuse with each other after co-firing. The rest is embedded in the ceramic body to stabilize the external electrode.

[0102] Based on the above embodiments, optionally, after the sintering step, the method may further include:

[0103] Chamfering step: round the sharp corners of the cut product.

[0104] Silver terminal steps: Silver is coated on the side or end of the product to lead out the device port.

[0105] Electroplating steps: such as Ni electroplating and Sn electroplating, to form a pad plating layer on the external electrode to improve the soldering performance of the device.

[0106] It should be understood that the various forms of processes shown above can be used to reorder, add or delete steps. For example, the steps described in the present invention can be executed in parallel, sequentially or in different orders, as long as the desired results of the technical solution of the present invention can be achieved, and this document does not limit this.

[0107] The above specific implementations do not constitute a limitation on the protection scope of the present invention. It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and substitutions can be made according to design requirements and other factors. Any modification, equivalent substitution and improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A ceramic substrate, characterized in that: include: A first ceramic dielectric layer; a slot is formed on one side of the first ceramic dielectric layer, and a first auxiliary electrode is filled in the slot; The first electrode layer is arranged on one side of the first ceramic dielectric layer where the slot is opened; the first electrode layer includes a first electrode, and the first electrode is connected to the first auxiliary electrode.

2. The ceramic substrate according to claim 1, characterized in that: The slot is a circular hole, an elliptical hole or a square hole; Alternatively, the opening area of ​​the slot gradually increases in a direction away from the first electrode layer.

3. The ceramic substrate according to claim 1, characterized in that: The adhesion between the first auxiliary electrode and the first ceramic dielectric layer is greater than or equal to the adhesion between the first electrode and the first ceramic dielectric layer; and / or, The adhesion between the first electrode and the first auxiliary electrode is greater than the adhesion between the first electrode and the first ceramic dielectric layer.

4. The ceramic substrate according to any one of claims 1 to 3, characterized in that: The first auxiliary electrode and the first electrode are made of the same material; And / or, the first electrode covers a surface of the first auxiliary electrode close to the first electrode layer, and a vertical projection area of ​​the first electrode on the first ceramic dielectric layer is larger than an area of ​​a surface of the first auxiliary electrode close to the first electrode layer.

5. A low temperature co-fired ceramic device, characterized in that: include: The ceramic substrate according to any one of claims 1 to 4, and at least one inner electrode substrate stacked with the ceramic substrate; Wherein, the first electrode in the ceramic substrate serves as an external electrode exposed on the surface of the low-temperature co-fired ceramic device; Each of the inner electrode substrates includes a second ceramic dielectric layer; at least one of the inner electrode substrates includes a second electrode layer, and the second electrode layer is arranged on a side of the second ceramic dielectric layer in the inner electrode substrate close to the ceramic substrate.

6. The low temperature co-fired ceramic device according to claim 5, characterized in that: The inner electrode substrate adjacent to the ceramic substrate includes the second electrode layer; In the inner electrode substrate adjacent to the ceramic substrate, the second electrode layer includes: a second auxiliary electrode; the slot and the first auxiliary electrode both penetrate the first ceramic dielectric layer; the second auxiliary electrode is connected to a side of the first auxiliary electrode away from the first electrode; The area of ​​the vertical projection of the second auxiliary electrode on the first ceramic dielectric layer is larger than the area of ​​the surface of the first auxiliary electrode away from the first electrode layer.

7. The low temperature co-fired ceramic device according to claim 5 or 6, characterized in that: At least part of the film layers in the first ceramic dielectric layer and each of the second ceramic dielectric layers also include structural holes that penetrate the film layers, and the structural holes are filled with via electrodes; wherein, in the first electrode layer and each of the second electrode layers, different layers are connected through the via electrodes.

8. A method for preparing a low temperature co-fired ceramic device, characterized in that: Used to prepare a low temperature co-fired ceramic device as described in any one of claims 5 to 7; The method for preparing the low temperature co-fired ceramic device comprises: A ceramic substrate and at least one inner electrode substrate are provided; wherein the ceramic substrate comprises a first ceramic dielectric layer and a first electrode layer which are stacked; a slot is provided on one side of the first ceramic dielectric layer, and a first auxiliary electrode is filled in the slot; the first electrode layer is provided on the side of the first ceramic dielectric layer where the slot is provided; the first electrode layer comprises a first electrode, and the first electrode is connected to the first auxiliary electrode; each of the inner electrode substrates comprises a second ceramic dielectric layer, and at least one of the inner electrode substrates comprises a second electrode layer provided on one side of the second ceramic dielectric layer; the ceramic substrate and each of the inner electrode substrates comprise positioning holes; Based on each of the positioning holes, the ceramic substrate and each of the internal electrode substrates are laminated and pressed to obtain a laminated structure; wherein the first electrode layer is exposed on the surface of the laminated structure; in the laminated structure, the second electrode layer is located on the side of the second ceramic dielectric layer in the internal electrode substrate close to the ceramic substrate.

9. The method for preparing a low-temperature co-fired ceramic device according to claim 8, characterized in that: Providing the ceramic substrate comprises: Providing the first ceramic dielectric layer, and preparing the positioning holes, the slot holes and the structural holes on the first ceramic dielectric layer; Filling the slot to form the first auxiliary electrode; and filling the structural hole to form a via electrode; The first electrode layer is prepared on one side of the first ceramic dielectric layer where the slot is opened; Providing the inner electrode substrate includes: Providing the second ceramic dielectric layer, and preparing the positioning holes and the structural holes on the second ceramic dielectric layer; Filling the structural hole to form a via electrode; For the inner electrode substrate including the second electrode layer, after the structural hole is filled to form the via electrode, the method further comprises: preparing the second electrode layer on one side of the second ceramic dielectric layer; Wherein, in the stacked structure, different layers in the first electrode layer and each of the second electrode layers are connected through the via electrodes.

10. The method for preparing a low-temperature co-fired ceramic device according to claim 8, characterized in that: After obtaining the laminated structure, it also includes: Cutting the stacked structure to obtain a device substrate; Debinding the device substrate; The device substrate after debinding is sintered to obtain a low temperature co-fired ceramic device.

Images