LTCF device with air cavity and manufacturing method thereof
Technical Field
The invention relates to the technical field of LTCF devices, in particular to an LTCF device with an air cavity and a manufacturing method thereof.
Background
Compared with the traditional magnetic device, the LTCF (low temperature co-fired ferrite) magnetic device has the remarkable advantages of small volume and light weight. As the volume of the magnetic device becomes smaller, the anti-saturation performance of the device decreases significantly. The traditional magnetic device generally adopts a mode of manufacturing air gaps on magnetic rings to improve the anti-saturation performance of the device, but the LTCF magnetic device is of a multilayer chip structure, does not have the magnetic rings, and cannot improve the performance by using the traditional process.
At present, a commonly used method for improving the anti-saturation performance of the LTCF is to print a dielectric material with low magnetic permeability on a green ceramic chip, and the number of layers of the dielectric material is generally equivalent to that of a circuit coil. The efficiency of improving the anti-saturation performance by using the dielectric material is low, and the inductance of an inductor of the printed dielectric material is measured to be 124 mu H and the self-resonant frequency is 2190 kHz. The dielectric material needs to be matched and developed for ferrite materials with various labels, and because the dielectric material is a heterogeneous material with a device substrate ferrite, the multilayer dielectric material is easy to cause the cracking and deformation defects of the device after isostatic pressing or sintering.
Disclosure of Invention
It is an object of the present invention to provide an ltcc device with an air cavity to solve the above problems.
In order to achieve the purpose, the technical scheme adopted by the invention is as follows: the utility model provides a LTCF device with air cavity, air cavity is located inside the LTCF device, just air cavity does not have the air intercommunication with the external world, the cubical space of air cavity is provided with metallized through-hole and metallization circuit all around.
The air cavity is arranged in a device, metallized through holes and metallized circuits are arranged around the space of the air cavity, and the air cavity needs to avoid the metallized through holes which are communicated up and down; the air cavity performs the function of an air gap in a conventional magnetic device inside the device.
The second objective of the present invention is to provide a method for manufacturing the ltcc device, which adopts a technical scheme that the method comprises the following steps:
(1) respectively manufacturing a chin block above the air cavity and a chin block below the air cavity;
(2) manufacturing the air cavity on the chin block obtained in the step (1);
(3) connecting and fixing the upper jaw block and the lower jaw block into a whole to obtain a semi-finished product;
(4) and (4) further pressing the semi-finished product obtained in the step (3) to enable the semi-finished product to be connected into a whole, and enabling the semi-finished product and the air cavity in the semi-finished product not to deform, so that the air-conditioning plate is obtained.
Preferably, in step (2), the method for forming the air cavity is a laser or mechanical method.
In a preferable technical scheme, in the step (3), the connection and fixation method includes clamp alignment and adhesive bonding.
As a preferable embodiment, the step (4) is carried out at 60 ℃ under 0.1 MPa.
The method improves the mode of printing the medium material commonly used at present, avoids the complicated research and development of the medium material and various defects caused by the medium material, does not use the medium material, and thus avoids the cracking and deformation caused by heterogeneous materials.
The method is different from the traditional method of manufacturing the internal cavity by using the sacrificial material, does not need to manufacture a sacrificial material discharge hole, keeps the appearance integrity and the air tightness of the device, and does not have the residual sacrificial material.
Compared with the prior art, the invention has the advantages that: according to the invention, the internal air cavity is manufactured in the LTCF device, a high-efficiency air gap structure is added in the LTCF device, a solution is provided for improving the anti-saturation performance of the device, and an air cavity inductor with the same base material and the same turn number as those of the air cavity inductor in the background technology is actually measured, so that the inductance value is 101 mu H, and the self-resonant frequency is 2530 kHz.
Drawings
FIG. 1 is a schematic view of an exploded view of an LTCF device of the present invention;
fig. 2 is a cross-sectional view of an LTCF device of the present invention.
In the figure: 1. a base material; 2. an air cavity; 3. a Shangbai block; 4. a chin block; 5. metallizing the through-hole; 6. and (4) metalizing the circuit.
Detailed Description
The invention will be further explained with reference to the drawings.
Example (b):
referring to fig. 1-2, an ltcc device with an air cavity comprises a base material 1 and an air cavity 2, wherein the air cavity 2 is located inside the ltcc device, the air cavity 2 is not communicated with the outside, and metallized through holes 5 and metallized circuits 6 are arranged around a three-dimensional space of the air cavity 2.
The preparation method of the device comprises the following steps:
(1) pulping and tape casting: fully mixing ferrite powder with various organic matters to obtain a mixture, uniformly casting the mixture on a PET (polyethylene terephthalate) film by using a casting machine, drying to form a ferrite green ceramic tape, and cutting the green ceramic tape to form a ferrite green ceramic chip;
(2) punching: manufacturing a through hole on the ferrite green chip by using a punching machine, wherein the through hole comprises a circuit communication hole, a layer number mark and an alignment mark hole;
(3) filling holes: filling metal slurry in the circuit communication hole and drying to complete the metallized through hole 5;
(4) printing: printing metal slurry on the green ceramic chip and drying to form a metallized circuit 6;
(5) laminating: respectively laminating a plurality of layers of green ceramic chips on the upper part and the lower part of the air cavity 2 to form two blocks to be processed;
(6) isostatic pressing: performing isostatic pressing on the two blocks manufactured in the step (5) to form a chin block 3 and a chin block 4;
(7) opening an air cavity: manufacturing an air cavity 2 with a preset shape and depth on the surface of a chin block 4 by using a laser or a mechanical mode;
(8) bonding: aligning by using an alignment fixture, bonding by using an adhesive, combining the upper jaw block 3 and the lower jaw block 4 into a whole, and applying the temperature of 60 ℃ and the pressure of 0.1MPa to ensure that the combination is tight and the appearance and the cavity are not deformed to obtain a semi-finished product;
(9) slitting: cutting the semi-finished product manufactured in the step (8) into independent devices, wherein the number of the devices is different from tens of devices to hundreds of devices according to the size of the devices;
(10) rubber discharging and sintering: and (5) removing glue and sintering the device to form a finished device.
(11) And testing and packaging.
The step (7) and the step (8) are the innovative method of the present invention, and other process steps are the same as those of the existing LTCF process, which is the prior art. By the innovative method, an air gap structure similar to the traditional magnetic ring slotting process is provided for the miniaturized multilayer chip type magnetic device, and high-efficiency anti-saturation capacity is formed.
The cavity can be made into a ring-shaped structure as shown in figure 1, a metalized through hole can be formed in the position of the ring center to form the communication of an upper circuit and a lower circuit, and the function cannot be met by a sacrificial material method.
The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents and improvements made within the spirit and principle of the present invention are intended to be included within the scope of the present invention.