Preparation method of laminated chip inductor

Abstract

The invention relates to a preparation method of a laminated chip inductor, and belongs to the technical field of laminated chip inductor preparation. The preparation method of the laminated chip inductor sequentially comprises the steps of sanding and burdening, curtain coating, punching, electrode printing and lamination pressing in the integral forming stage, and vacuum holes of a printing platform of a printing machine comprise dense holes located in the periphery of the printing platform and sparse holes located in the center of the printing platform; when the electrode is printed, the area of the electrode pattern area is not less than 90% of the total area of the diaphragm. According to the preparation method, the height difference can be avoided, and the pressing difficulty is reduced, so that the overlying pressure during overlying forming is reduced, the overlying deformation is reduced, the number of cut electrodes is reduced, the sensitivity consistency is improved, and the qualified rate and the hit rate of products are improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of the preparation of multilayer chip inductors, and particularly relates to a method for preparing a multilayer chip inductor. Background Art

[0002] At present, the dry forming method of multilayer chip inductors includes steps of abrasive mixing, casting, punching, printing electrodes, and laminating. Among them, the printing of electrodes mainly adopts a non-full-surface printing method at present. The area of the electrode pattern region generally accounts for 60% - 70% of the total area of the film sheet, and there are no printed electrodes around the film sheet, resulting in a height difference between the surrounding area and the middle electrode pattern area. During lamination, the surrounding area is not pressed tightly enough; especially when laminating multiple layers of electrodes, the height difference between the middle electrode pattern area and the electrode-free area around accumulates with the number of layers, and the surrounding area of the film sheet is even less tightly pressed, resulting in the area without printed electrodes around being easily lifted during lamination, forming a torn effect. In order to reduce the tearing problem, a higher lamination pressure needs to be used during lamination, and the high lamination pressure will make the electrodes on the film sheet more likely to be flattened and deformed. Due to the inconsistency of the deformation, the inductance of the product will be inconsistent; at the same time, since the electrodes are flattened, the distance between the electrodes becomes smaller, and it is easier to cut out the electrodes during the process of cutting and separating the products, resulting in the electrodes being exposed outside the products and causing short-circuit failure.

[0003] Therefore, it is urgent to develop a new printing method to reduce the lamination pressure and improve the problems of inconsistent inductance and cutting out electrodes caused by high lamination pressure. Summary of the Invention

[0004] The purpose of the present invention is to overcome the problems existing in the above-mentioned prior art, and provide a method for preparing a multilayer chip inductor.

[0005] The present invention is realized through the following technical solutions:

[0006] A method for preparing a multilayer chip inductor, which sequentially includes steps of abrasive mixing, casting, punching, printing electrodes, and laminating in the overall forming stage. Among them,

[0007] The vacuum holes on the printing platform of the printing machine include dense holes located around the printing platform and sparse holes located at the center of the printing platform;

[0008] When printing the electrodes, the area of the electrode pattern region is not less than 90% of the total area of the film sheet.

[0009] In the preparation method of the present invention, the method of printing electrodes is changed from the method of not printing electrodes around the diaphragm (the electrode pattern area accounts for 60-70% of the total area of the diaphragm) to the method of printing electrodes on the entire surface of the diaphragm (the area of the electrode pattern area accounts for 90% or more of the total area of the diaphragm), which can avoid height differences, reduce the difficulty of lamination, thereby reducing the lamination pressure during lamination molding, reducing lamination deformation, further reducing the cut-out electrodes and improving the consistency of the inductance value, thus improving the qualification rate and hit rate of the product. Since electrodes are printed on the entire surface, there are also printed electrodes at the edge of the diaphragm. There is a printing off-net force. If the adsorption force of the printing platform on the diaphragm is insufficient, the edge of the diaphragm will be lifted during off-net, resulting in printing displacement. Therefore, the present invention further changes the design of the vacuum holes on the printing platform of the printing machine from sparse holes around to dense holes around + sparse holes in the middle, increasing the vacuum adsorption force of the platform on the periphery of the diaphragm during printing to meet the requirements of printing off-net at the edge of the diaphragm printed on the entire surface.

[0010] Preferably, the aperture of the dense holes is 0.4 mm - 0.8 mm.

[0011] Preferably, the hole distribution density of the dense holes at the printing start position and the end position is 25 - 35 per cm 2 , and the unilateral distribution width is 6 mm - 12 mm.

[0012] Preferably, the hole distribution density of the dense holes on both sides parallel to the printing direction is 15 - 35 per cm 2 , and the unilateral distribution width is 4 mm - 12 mm.

[0013] Preferably, the aperture of the sparse holes is 0.6 mm - 1.2 mm.

[0014] Preferably, the distribution density of the sparse holes is 5 - 10 per cm 2 .

[0015] Preferably, the distribution area of the sparse holes is 16 cm 2 ~36 cm 2 .

[0016] The dense holes and sparse holes described in the present invention can have the same aperture or different apertures, and can be regularly arranged or irregularly arranged. Within the above preferred ranges, the effects of the present invention can be achieved.

[0017] Preferably, when the printing platform adsorbs the diaphragm, it first performs intermediate adsorption, and then performs edge adsorption after 20 ms - 50 ms.

[0018] Preferably, when printing the electrodes, the distances between the printing start position and the end position and the edge of the electrode pattern are both not less than 10 mm.

[0019] Preferably, when printing the electrode, the height of the printing screen is 1.2 mm to 2.2 mm.

[0020] Preferably, when printing the electrode, the printing speed is 50 mm / s to 80 mm / s.

[0021] The present invention further optimizes the printing parameters. Under the above-mentioned printing screen height and printing speed, combined with the vacuum hole design of the printing platform of the present invention, the printing quality can be effectively guaranteed.

[0022] The present invention has the following beneficial effects: In the preparation method of the present invention, the printing area of the electrode is increased, and a lower lamination pressure can be used for lamination molding during lamination, reducing lamination deformation, reducing the cut-out electrode and improving the inductance consistency, thereby improving the product qualification rate and hit rate. And the whole-surface printing with film to make products makes the utilization rate of the green sheet higher and has better economic benefits. Description of the Drawings

[0023] Figure 1 is the main process flow chart of the existing multilayer chip inductor;

[0024] Figure 2 is the schematic diagram of the distribution of vacuum holes on the printing platform of the printing machine in the prior art;

[0025] Figure 3 is the schematic diagram of the printing electrode method in the prior art;

[0026] Figure 4 is the schematic diagram of the distribution of vacuum holes on the printing platform of the printing machine of the present invention;

[0027] Figure 5 is the schematic diagram of the printing electrode method of the present invention. Detailed Embodiments

[0028] To better illustrate the purpose, technical solution and advantages of the present invention, the present invention will be further described below in conjunction with specific embodiments. Those skilled in the art should understand that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0029] Unless otherwise specified, the test methods used in the examples are all conventional methods; the materials, reagents, etc. used, unless otherwise specified, can all be obtained from commercial channels.

[0030] Currently, the main preparation process for multilayer chip inductors is the casting-printing-lamination process, and its specific process is as Figure 1 shown. Among them, in the overall product forming stage, it mainly includes sanding and batching, casting, punching, printing electrodes, and lamination steps, while in the post-forming processing stage, it mainly includes: cutting, firing, chamfering, end capping, electroplating, appearance testing, and warehousing steps.

[0031] In the prior art, the schematic diagram of the vacuum hole distribution on the printing platform of a printing press is as Figure 2 shown, and the schematic diagram of the printing electrode method is Figure 3 shown, Figure 3 For non-full-surface printing, the electrode pattern area generally accounts for 60% - 70% of the total area of the diaphragm. There is no printed electrode around the diaphragm, resulting in a height difference between the surrounding area and the middle electrode pattern area. When the lamination pressure is too high, it will cause inconsistent inductance of the inductor and electrode cutting problems. In the method for preparing an inductor of the present invention, the schematic diagram of the vacuum hole distribution on the printing platform of the printing press is as Figure 4 shown, and the schematic diagram of the printing electrode method is as Figure 5 shown. By making the area of the electrode pattern area not less than 90% of the total area of the diaphragm, the height difference is reduced, the lamination pressure is reduced, and the adsorption force on the diaphragm is increased by changing the vacuum hole setting scheme of the printing platform, avoiding printing displacement. The present invention is further illustrated by the following embodiments.

[0032] The following description of the method for preparing a multilayer chip inductor is applied to a multilayer chip ceramic 060303 specification inductor:

[0033] Basic production conditions of the product: 6-inch green body, green tape diaphragm thickness 15μm, 12 layers of electrodes, electrode thickness 15μm, electrode width 50μm, designed cutting margin 50μm, designed inductance 10nH.

[0034] Embodiment 1

[0035] A method for preparing a multilayer chip inductor, which sequentially includes steps of sanding and mixing ingredients, casting, punching holes, printing electrodes, and lamination in the overall forming stage. Among them,

[0036] The vacuum holes on the printing platform of the printing press are dense holes located around the printing platform and sparse holes located at the center of the printing platform;

[0037] The design of the dense holes is as follows:

[0038] The aperture of the dense holes is 0.6mm;

[0039] The hole distribution density of the dense holes at the starting and ending positions of printing is 30 holes / cm 2 , and the unilateral distribution width is 9mm;

[0040] The hole distribution density of the dense holes on both sides parallel to the printing direction is 25 holes / cm 2 , and the unilateral distribution width is 8mm;

[0041] The design of the sparse holes is as follows:

[0042] The aperture of the sparse holes is 0.9mm;

[0043] The distribution density of the sparse holes is 8 holes / cm 2 ;

[0044] The distribution area of the sparse holes is 26 cm 2 ;

[0045] When the printing platform adsorbs, it first performs intermediate adsorption, and then performs edge adsorption 35 ms later;

[0046] The parameters for printing the electrode are as follows:

[0047] The distances between the printing start position and the printing end position and the edge of the electrode pattern are 10 mm;

[0048] The printing screen height is 1.7 mm;

[0049] The printing speed is 65 mm / s.

[0050] When printing the electrode, the area of the electrode pattern region is 90% of the total area of the diaphragm.

[0051] Example 2

[0052] A preparation method of a multilayer chip inductor, which successively includes steps of abrasive grinding batching, casting, punching holes, printing electrodes, and multilayer lamination in the overall forming stage. Among them,

[0053] The vacuum holes of the printing platform of the printing machine are dense holes located around the printing platform and sparse holes located at the center of the printing platform;

[0054] The design of the dense holes is as follows:

[0055] The aperture of the dense holes is 0.4 mm;

[0056] The hole distribution density of the dense holes at the printing start and end positions is 25 holes / cm 2 , and the unilateral distribution width is 6 mm;

[0057] The hole distribution density of the dense holes on both sides parallel to the printing direction is 15 holes / cm 2 , and the unilateral distribution width is 4 mm;

[0058] The design of the sparse holes is as follows:

[0059] The aperture of the sparse holes is 0.6 mm;

[0060] The distribution density of the sparse holes is 5 holes / cm 2 ;

[0061] The distribution area of the sparse holes is 16 cm 2 ;

[0062] When the printing platform adsorbs, intermediate adsorption is first performed, and edge adsorption is performed 20 ms later;

[0063] The parameters for printing the electrodes are as follows:

[0064] The distances between the printing start and end positions and the edge of the electrode pattern are 10 mm;

[0065] The printing screen height is 1.2 mm;

[0066] The printing speed is 50 mm / s.

[0067] When printing the electrodes, the area of the electrode pattern region is 90% of the total area of the diaphragm.

[0068] Example 3

[0069] A method for preparing a multilayer chip inductor, which sequentially includes steps of abrasive grinding of the ingredients, casting, punching, printing electrodes, and multilayer lamination during the overall forming stage. Among them,

[0070] The vacuum holes of the printing platform of the printing machine are dense holes located around the printing platform and sparse holes located at the center of the printing platform;

[0071] The design of the dense holes is as follows:

[0072] The aperture of the dense holes is 0.8 mm;

[0073] The hole distribution density of the dense holes at the printing start and end positions is 35 holes / cm 2 , and the unilateral distribution width is 12 mm;

[0074] The hole distribution density of the dense holes on both sides parallel to the printing direction is 35 holes / cm 2 , and the unilateral distribution width is 12 mm;

[0075] The design of the sparse holes is as follows:

[0076] The aperture of the sparse holes is 1.2 mm;

[0077] The distribution density of the sparse holes is 10 holes / cm 2 ;

[0078] The distribution area of the sparse holes is 36 cm 2 ;

[0079] When the printing platform adsorbs, intermediate adsorption is first performed, and edge adsorption is performed 50 ms later;

[0080] The parameters for printing the electrodes are as follows:

[0081] The distances between the printing start and end positions and the edge of the electrode pattern are 10 mm;

[0082] The printing mesh height is 2.2 mm;

[0083] The printing speed is 80 mm / s.

[0084] When printing the electrodes, the area of the electrode pattern region is 90% of the total area of the diaphragm.

[0085] Comparative Example 1

[0086] The preparation method of the laminated chip inductor in this comparative example adopts the vacuum hole design and printing method of the printing platform in the prior art. The difference from Example 1 is that:

[0087] (1) The vacuum holes of the printing platform of the printing machine are sparse holes located around the printing platform, and the design of the sparse holes is:

[0088] The aperture of the sparse hole is 0.5 mm;

[0089] The hole distribution density of the sparse holes at the starting and ending positions of printing is 8 holes / cm 2 , and the unilateral distribution width is 3 mm;

[0090] The hole distribution density of the sparse holes on both sides parallel to the printing direction is 11 holes / cm 2 , and the unilateral distribution width is 1 mm;

[0091] (2) The parameters when printing the electrodes are:

[0092] The distances between the starting and ending positions of printing and the edge of the electrode pattern are 20 mm;

[0093] The printing mesh height is 0.8 mm;

[0094] The printing speed is 100 mm / s;

[0095] (3) When printing the electrodes, the area of the electrode pattern region is 65% of the total area of the diaphragm;

[0096] All other preparation parameters are the same as those in Example 1.

[0097] Comparative Example 2

[0098] The preparation method of the laminated chip inductor in this comparative example adopts the vacuum hole design of the printing platform and 90% graphic area printing in the prior art. The difference from Example 1 is that:

[0099] The vacuum holes of the printing platform of the printing machine are sparse holes located around the printing platform, and the design of the sparse holes is:

[0100] The aperture of the sparse hole is 0.5 mm;

[0101] The pore distribution density of the porous holes at the starting and ending positions of printing is 8 holes / cm 2 , and the unilateral distribution width is 3 mm;

[0102] The pore distribution density of the porous holes on both sides parallel to the printing direction is 11 holes / cm 2 , and the unilateral distribution width is 1 mm;

[0103] All other preparation parameters are the same as those in Example 1.

[0104] Comparative Example 3

[0105] The preparation method of the laminated chip inductor in this comparative example uses 90% graphic area printing. The difference from Example 1 is that:

[0106] The parameters during electrode printing are as follows:

[0107] The distances between the starting and ending positions of printing and the edges of the electrode pattern are 20 mm;

[0108] The printing screen height is 0.8 mm;

[0109] The printing speed is 100 mm / s;

[0110] All other preparation parameters are the same as those in Example 1.

[0111] The implementation effects of the methods in the examples and comparative examples are shown in Table 1 below.

[0112] Note 1: In Table 1, the lamination pressure is the minimum pressure that can ensure no tearing, bubbling, or insufficient pressing during lamination under the same lamination temperature and time, and can meet the lamination effect standard.

[0113] Note 2: In Table 1, "printing effect OK" means that multiple dimensions such as the printed line width, silver thickness, printing diffusion, hole filling effect, deformation degree of the printed electrode, connection offset situation, and printing accuracy all meet the standards.

[0114] Note 3: Under the basic production conditions of the above products, the acceptance criteria for the implementation effects are that the cut electrode ≤ 0.30% and the inductance standard deviation ≤ 0.10 nH.

[0115] Note 4: The margin is the distance between the inner electrode of the physical product (after cutting) and the side boundary of the product, which is measured through sampling slice DPA; the cut electrode ratio is calculated through post-process appearance sorting statistics; the inductance standard deviation is obtained by calculating the standard deviation of 1000 pcs of test data collected in the test process.

[0116] Table 1 Implementation effects of the methods in the examples and comparative examples

[0117]

[0118]

[0119] As can be seen from Table 1, the preparation method of the embodiment of the present invention has good printing effect for full-surface printing. At the same time, it reduces the area of the peripheral height difference region and increases the bonding force between the diaphragms. Therefore, it is possible to achieve lamination with a reduced lamination pressure, resulting in a significant decrease in the lamination pressure, a reduction in lamination deformation, and a significant decrease in the proportion of cut electrodes, which is reduced from 0.57% to below 0.30%. The standard deviation of the inductance value is reduced from 0.12 nH to below 0.10 nH. It effectively overcomes the problems of inconsistent inductance value and cut electrodes caused by the currently high lamination pressure, thereby improving the qualified rate and hit rate of the product.

[0120] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit the protection scope of the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present invention can be modified or equivalently replaced without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. A method for preparing a laminated chip inductor, which comprises the steps of sanding, casting, punching, printing electrodes, and laminating and pressing in the overall forming stage, characterized in that: The vacuum holes of the printing platform of the printing machine include dense holes located around the printing platform and sparse holes located in the center of the printing platform; When printing the electrodes, the area of ​​the electrode pattern region is not less than 90% of the total area of ​​the membrane.

2. The manufacturing method of the multilayer chip inductor according to claim 1, characterized in that, The diameter of the dense pores is 0.4 mm to 0.8 mm.

3. The manufacturing method of the multilayer chip inductor according to claim 1, characterized in that The hole distribution density of the dense holes at the printing start position and the end position is 25 to 35 holes / cm 2 , and the unilateral distribution width is 6 mm to 12 mm.

4. The manufacturing method of the stacked chip inductor according to claim 1, characterized in that, The density of the distribution of the fine holes on both sides parallel to the printing direction is 15 to 35 holes / cm 2 , and the unilateral distribution width is 4 mm to 12 mm.

5. The manufacturing method of the multilayer chip inductor according to claim 1, characterized in that, The aperture of the sparse holes is 0.6 mm to 1.2 mm.

6. The manufacturing method of the multilayer chip inductor according to claim 1, characterized in that, The distribution density of the pores is 5 to 10 pores / cm 2 .

7. The manufacturing method of the multilayer chip inductor according to claim 1, characterized in that, The distribution area of the pores is 16 cm 2 to 36 cm 2 .

8. The manufacturing method of the multilayer chip inductor according to claim 1, characterized in that When the printing platform adsorbs the film, it first performs middle adsorption, and then performs edge adsorption after 20ms to 50ms.

9. The manufacturing method of the stacked chip inductor according to claim 1, characterized in that, When printing the electrode, the distance between the printing start position and the printing end position and the edge of the electrode pattern is not less than 10 mm.

10. The manufacturing method of the multilayer chip inductor according to claim 1, characterized in that, When printing the electrodes, the printing screen height is 1.2 mm to 2.2 mm, and the printing speed is 50 mm / s to 80 mm / s.

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