Magnetic core manufacturing method and magnetic part

Abstract

The invention discloses a magnetic core manufacturing method and a magnetic part. The magnetic core manufacturing method comprises the steps that the upper surface of a semiconductor base material is coated with a first shielding layer; a first groove vertically penetrating through the first shielding layer is formed, and a first exposed area is formed on the semiconductor substrate; arranging a first conductive layer on the upper surfaces of the first shielding layer and the first exposed region, and then removing the first shielding layer and the first conductive layer on the upper surface of the first shielding layer, so that a second exposed region is formed on the semiconductor substrate; coating a second shielding layer on the upper surfaces of the first conductive layer and the second exposed area, wherein the second shielding layer is divided into a first part located on the upper surface of the first conductive layer and a second part located on the upper surface of the second exposed area; a second groove penetrating through the second shielding layer is formed in the first part of the second shielding layer, so that a third exposed area is formed on the first conductive layer; arranging a magnetic film layer on the upper surface of the third exposed area; and removing the remaining second part in the second shielding layer. According to the invention, the wet etching patterning defect can be avoided.

Description

Technical Field

[0001] The present invention relates to magnetic components, and in particular to a method for manufacturing a magnetic core and a device. Background Art

[0002] Currently, with the rapid development of semiconductor manufacturing technology, the application frequency of power semiconductor devices in modular power supplies is continuously increasing while the loss is continuously decreasing; the "thin film type" micro magnetic components with a two-dimensional planar structure manufactured based on integrated circuit processes have replaced the three-dimensional structure magnetic components prepared by traditional manufacturing technologies, significantly reducing the volume of modular power supplies and conforming to the development trend of miniaturization and light weight of electronic products.

[0003] In modern technology, the micro magnetic components (generally referred to as on-chip magnetic components) manufactured using integrated processes can be roughly divided into two categories: air-core coils and micro magnetic components with magnetic cores. Compared with air-core coils, the micro magnetic components with magnetic cores (i.e., on-chip magnetic components with magnetism) have better EMI effects, higher inductance density, and better magnetic coupling coefficient, and thus have more development prospects.

[0004] In the manufacturing process of integrated circuits, a magnetic thin film preparation scheme in modern technology is to deposit a conductive seed layer on the surface of a single-wafer substrate, and then form a magnetic thin film by electroplating, and perform patterning and segmentation on the entire magnetic thin film wafer through dry etching or wet etching steps to remove the thick magnetic thin film metal remaining in the wafer cutting channel to avoid affecting wafer dicing, or reduce the eddy current loss of the metal magnetic thin film through patterning and segmentation. In this technology, the etching rate of dry etching is low and the manufacturing cost is high; wet etching is isotropic, the etching accuracy is not high, and it is easy to occur that the etching is incomplete and metal residues are left. Summary of the Invention

[0005] In view of the deficiencies of the above-mentioned prior art, the technical problem to be solved by the present invention is to provide a method for manufacturing a magnetic core and a magnetic component, which can at least to some extent solve the deficiencies of the above-mentioned prior art problems.

[0006] As the first aspect of the present invention, the technical solution of the embodiment of the provided method for manufacturing a magnetic core is as follows:

[0007] A method for manufacturing a magnetic core, which includes the following steps:

[0008] The first mask layer coating step: coating a first mask layer on the upper surface of the semiconductor substrate;

[0009] The first trench opening step: opening a first trench vertically penetrating the first mask layer on the first mask layer, so that a first exposed area is formed on the semiconductor substrate;

[0010] First conductive layer setting step: A first conductive layer is set on the upper surface of the first shielding layer and the upper surface of the first exposed area, and then the first shielding layer and the first conductive layer on its upper surface are removed, so that only the first conductive layer remains in the first trench, and a second exposed area is formed on the semiconductor substrate;

[0011] Second shielding layer coating step: A second shielding layer is coated on the upper surface of the first conductive layer and the upper surface of the second exposed area. The second shielding layer is divided into a first part located on the upper surface of the first conductive layer and a second part located on the upper surface of the second exposed area;

[0012] Second trench opening step: A second trench penetrating the second shielding layer is opened above the first part of the second shielding layer, so that a third exposed area is formed on the first conductive layer;

[0013] Magnetic thin film layer setting step: A magnetic thin film layer is set on the upper surface of the third exposed area;

[0014] Second shielding layer removing step: The remaining second part in the second shielding layer is removed.

[0015] Preferably, the thickness of the first shielding layer is greater than the thickness of the first conductive layer.

[0016] Preferably, the thickness of the second shielding layer is greater than the thickness of the magnetic thin film layer.

[0017] Preferably, the thickness of the first conductive layer is less than the thickness of the magnetic thin film layer.

[0018] Preferably, the sum of the projected areas of the magnetic thin film on the upper surface of the first conductive layer is less than the projected area of the first conductive layer on the upper surface of the semiconductor substrate.

[0019] Preferably, the material of the first conductive layer is nickel; or cobalt; or titanium; or any combination of two of nickel, cobalt, and titanium; or a combination of nickel, cobalt, and titanium.

[0020] Preferably, the magnetic thin film material includes any combination of two of iron, cobalt, and nickel; or includes a combination of iron, cobalt, and nickel.

[0021] As the second aspect of the present invention, the technical solution of the embodiment of the magnetic component is as follows:

[0022] A magnetic component, the magnetic component is a on-chip magnetic component, wherein: it includes a magnetic core manufactured by the magnetic core manufacturing method according to any item in the first aspect above.

[0023] Furthermore, the magnetic component further includes a conductive coil winding.

[0024] Further, the magnetic component further includes a dielectric layer disposed between the magnetic thin film layer and the conductive coil winding to insulate and cover the magnetic thin film and the conductive coil winding.

[0025] The beneficial effects of the present invention are as follows: The present invention optimizes the deposition methods of the conductive seed layer and the magnetic thin film. By the first masking layer coating step, the first trench opening step, and the first conductive layer setting step, a patterned first conductive layer is first fabricated, and then, through the second masking layer coating step, the second trench opening step, and the magnetic thin film layer setting step, the magnetic thin film layer is deposited only on the patterned first conductive layer. This method of fabricating the magnetic thin film layer after patterning the first conductive layer can avoid the problems of low dry etching rate in the prior art and patterning defects of the magnetic thin film layer caused by wet etching. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 is a flowchart of the magnetic core manufacturing method according to the first embodiment of the present invention;

[0027] Figure 2 is a partial structural schematic diagram of an intermediate product of the magnetic core manufacturing method according to the first embodiment of the present invention along the vertical direction of the semiconductor substrate;

[0028] Figures 3a to 3i is Figure 2 a schematic diagram of the corresponding structure along the horizontal direction of the semiconductor substrate;

[0029] Figure 4 is a specific structural diagram of the magnetic component according to the second embodiment of the present invention;

[0030] Among them, the reference numerals are summarized as follows:

[0031] Semiconductor substrate 101, first masking layer 102, first conductive layer 103, second masking layer 104, magnetic thin film layer 105, conductive coil winding 106. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0032] Hereinafter, the technical solutions in the present application will be clearly and completely described in conjunction with the accompanying drawings. Apparently, the described embodiments are some, but not all, of the embodiments of the present application. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present application without creative efforts shall fall within the scope of protection of the present application.

[0033] In the description of the present application, it should be noted that the orientation or positional relationship indicated by terms such as "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be construed as a limitation on the present application. In addition, terms such as "first", "second", "third", "step 1", "step 2", etc. are only used for descriptive purposes and cannot be construed as indicating or implying relative importance.

[0034] In addition, the technical features involved in different embodiments of the present application described below can be combined with each other as long as they do not conflict with each other.

[0035] First Embodiment

[0036] A method for manufacturing a magnetic core, Figure 1 is a flowchart of the method for manufacturing a magnetic core according to the first embodiment of the present invention, Figure 2 is a partial structural schematic diagram of an intermediate product of the method for manufacturing a magnetic core according to the first embodiment of the present invention along the vertical direction of a semiconductor substrate, Figures 3a to 3i is Figure 2 a schematic diagram of the corresponding structure along the horizontal direction of the semiconductor substrate. Refer to Figure 1 , the method for manufacturing a magnetic core in this embodiment includes the following steps:

[0037] S100, the first shielding layer coating step, coating a first shielding layer 102 on the upper surface of the semiconductor substrate 101. Please refer to Figure 2 , where S1 is a structural schematic diagram of the semiconductor substrate 101, and S2 is a structural schematic diagram of the intermediate product after this step. Figure 3a is Figure 2 a schematic diagram of S1 along the horizontal direction of the semiconductor substrate in Figure 3b is Figure 2 a schematic diagram of S2 along the horizontal direction of the semiconductor substrate in

[0038] The semiconductor substrate 101 in this embodiment can be a pure semiconductor material substrate, such as a silicon substrate, a sapphire substrate, or a compound substrate, etc. At this time, the surface material of the semiconductor substrate is silicon, or sapphire, or a compound; it can also be a substrate deposited with other materials, such as a substrate spin-coated with PI. At this time, the substrate surface is PI material; specifically, how to select a semiconductor substrate is not limited in the present invention, and those skilled in the art can select according to needs;

[0039] Specifically, the first shielding layer 102 can be made of a photoetching agent material (i.e., photoresist), and can be uniformly coated on the upper surface of the semiconductor substrate 101 by means of spin coating, spraying, dip coating, etc., and completely cover the upper surface of the semiconductor substrate 101. Then, it is necessary to pre-bake and cure the first shielding layer 102 through a hot plate. The baking conditions are set in combination with the requirements of the photoetching agent material and the thickness of the first shielding layer 102. In combination with this method, a negative photoresist is preferably used, and the thickness of the photoresist as the first shielding layer is generally set above 3um;

[0040] S200, the first trench opening step, open a first trench vertically penetrating the first shielding layer 102 on the first shielding layer 102, so that a first exposed area is formed on the semiconductor substrate 101. Please refer to Figure 2 , where S3 is a schematic structural diagram of the intermediate product for completing this step, Figure 3c is Figure 2 a schematic diagram of S3 in

[0041] Specifically, it is preferable to pattern the first shielding layer 102 through photolithography techniques (such as exposure, development, etc.) to open the first trench. The specific steps include exposure and development. Before exposure, a mask plate is used for partial shielding, and after exposure, the first shielding layer 102 is etched with a developer. If the first shielding layer 102 uses a positive photoresist, the material of the first shielding layer 102 in the illuminated area will be etched and removed; if the first shielding layer 102 uses a negative photoresist, the material of the first shielding layer in the illuminated area will be retained, and the material of the first shielding layer in the unilluminated area will be etched and removed; as described in step S100, a negative photoresist is preferably used. Therefore, the material of the first shielding layer in the illuminated area will be retained, and the material of the first shielding layer in the unilluminated area is etched by the developer to form a through groove, exposing the upper surface of the substrate 101;

[0042] S300, the first conductive layer setting step, set a first conductive layer 103 on the upper surface of the first shielding layer and the upper surface of the first exposed area. Please refer to Figure 2 , where S4 is a schematic structural diagram of the intermediate product for completing this step, Figure 3d is Figure 2 a schematic diagram of S4 in Figure 2 along the horizontal direction of the semiconductor substrate, and then remove the first shielding layer and the first conductive layer on its upper surface, so that only the first conductive layer remains on the first trench, and a second exposed area is formed on the semiconductor substrate. Please refer to Figure 3e , where S5 is a schematic structural diagram of the intermediate product for completing this step, Figure 2 is

[0043] Specifically, the first conductive layer 103 may be deposited by sputtering, CVD or PECVD, evaporation, etc. The first conductive layer deposited by sputtering, CVD or PECVD, or evaporation will adhere to the upper surface of the first shielding layer and the upper surface of the first exposed area. Preferably, the thickness of the deposited first conductive layer should be less than or equal to one third of the thickness of the first shielding layer, and the conductive layer should be avoided from being deposited on the sidewall of the first groove as much as possible, so that the conductive layer on the upper surface of the first exposed area is connected with the conductive layer on the upper surface of the first shielding layer 102 through the conductive layer on the sidewall of the first groove, thereby affecting the effect of removing the first shielding layer.

[0044] The first shielding layer and the first conductive layer on its upper surface can be removed by a degumming process, generally by immersing in a photoresist degumming solution. The first shielding layer 102 will dissolve and fall off during the immersion in the degumming solution, and at the same time, the first conductive layer on the upper surface of the first shielding layer 102 will be separated from the upper surface of the semiconductor substrate, so that only the patterned first conductive layer remains on the upper surface of the semiconductor substrate 101.

[0045] S400, a second shielding layer coating step, coating a second shielding layer 104 on the upper surface of the first conductive layer 103 and the upper surface of the second exposed area, the second shielding layer is divided into a first portion located on the upper surface of the first conductive layer and a second portion located on the upper surface of the second exposed area, see Figure 2 , where S6 is a schematic diagram of the structure of the intermediate product that completes this step, Figure 3f for Figure 2 Schematic diagram of S6 along the horizontal direction of the semiconductor substrate;

[0046] Specifically, a photoresist material (photoresist) can be evenly coated on the upper surface of the first conductive layer 103 and the upper surface of the exposed semiconductor substrate 101 by spin coating, spray coating, dip coating, etc. It is also preferred to use a negative photoresist in this step. The thickness of the photoresist used as the second shielding layer 104 is generally set to be more than twice the required thickness of the magnetic film.

[0047] S500, a second groove opening step, opening a second groove penetrating the second shielding layer on the first portion of the second shielding layer, so that a third exposed area is formed on the first conductive layer, see Figure 2 , where S7 is a schematic diagram of the structure of the intermediate product that completes this step, Figure 3g for Figure 2 Schematic diagram of S7 along the horizontal direction of the semiconductor substrate;

[0048] This step is the same as the first trench opening step, and its purpose is to expose the area of ​​the first conductive layer 103 where the magnetic film layer needs to be set, and to shield the area where the magnetic film layer does not need to be set but needs to be conductive.

[0049] S600, Step of setting the magnetic thin film layer 105. Set the magnetic thin film layer 105 on the upper surface of the third exposed area. Please refer to Figure 2 , where S8 is the schematic structural diagram of the intermediate product after completing this step. Figure 3h is Figure 2 the schematic diagram of S8 in the horizontal direction of the semiconductor substrate in

[0050] Specifically, the magnetic thin film layer 105 can be prepared by electrochemically depositing. Put the semi-finished product obtained in step S500 into the magnetic thin film electroplating solution. The cathode of the electroplating equipment is in contact with the first conductive layer 103, and the anode of the electroplating equipment is in contact with the electroplating solution. The magnetic thin film starts to grow in the set channel-shaped through groove, and the growth thickness is controlled to be lower than the thickness of the second shielding layer 104.

[0051] S700, Step of removing the second shielding layer. Remove the remaining second part in the second shielding layer. Please refer to Figure 2 , where S9 is the schematic structural diagram of the intermediate product after completing this step. Figure 3i is Figure 2 the schematic diagram of S9 in the horizontal direction of the semiconductor substrate in

[0052] This step is the same as the method of removing the first shielding layer and the first conductive layer on its upper surface in step S300. Remove the remaining second shielding layer by the degluing solution.

[0053] Since there is no dry etching or wet etching step in the method of manufacturing the magnetic core in this embodiment, after completing step S700 of removing the second shielding layer and completing the dicing and slicing of the magnetic component wafer, a part of the cut surface of the first conductive seed layer will be exposed on the side wall of a single magnetic component wafer, that is Figure 4 the cut surface of the 103 first conductive seed layer in

[0054] In the method of manufacturing the magnetic core in this embodiment, the first conductive layer and the magnetic thin film layer do not adopt the method of first preparing the magnetic thin film on the entire wafer and then performing patterned etching. Instead, through the first shielding layer coating step, the first trench opening step and the first conductive layer setting step, a patterned first conductive layer is first manufactured, and then through the second shielding layer coating step, the second trench opening step and the magnetic thin film layer setting step, the magnetic thin film layer is only set on the patterned first conductive layer. This method of preparing the magnetic thin film layer after patterning the first conductive layer can save the steps of dry etching or wet etching, save costs, and at the same time can avoid the problem of patterned defects of the magnetic thin film layer caused by wet etching in the prior art.

[0055] Preferably, the thickness of the first shielding layer is greater than that of the first conductive layer to prevent the entire surface of the first conductive layer from covering the first shielding layer and affecting the removal effect of the first shielding layer.

[0056] Preferably, the thickness of the second shielding layer is greater than that of the magnetic thin film layer to prevent the magnetic thin film layer from forming a continuous film on the top of the second shielding layer and failing to achieve a patterning effect.

[0057] Preferably, the thickness of the first conductive layer is less than that of the magnetic thin film layer to reduce the risk of damaging the dicing fixture during wafer dicing.

[0058] Preferably, the sum of the projected areas of the magnetic thin films on the upper surface of the first conductive layer is less than the projected area of the first conductive layer on the upper surface of the semiconductor substrate, so that the magnetic thin films will not be diced and the blade will not be damaged during wafer dicing.

[0059] Preferably, the material of the first conductive layer is nickel; or cobalt; or titanium; or any combination of two of nickel, cobalt, and titanium; or a combination of nickel, cobalt, and titanium.

[0060] Preferably, the magnetic thin film material includes any combination of two of iron, cobalt, and nickel; or a combination of iron, cobalt, and nickel.

[0061] Second Embodiment

[0062] The magnetic component provided in this embodiment is a on-chip magnetic component, which includes: a magnetic core manufactured by any of the magnetic core manufacturing methods in the first embodiment.

[0063] Furthermore, the magnetic component further includes a conductive coil winding. The pattern of the conductive coil winding can adopt a planar spiral coil structure or a solenoid coil structure. The position of the conductive coil winding, the number of layers and the position of each layer when adopting the planar spiral coil structure design, etc. are not limited in the present invention, and those skilled in the art can select according to needs.

[0064] Figure 4 This is a specific structural diagram of the magnetic component in the second embodiment of the present invention, which is a planar spiral coil winding structure with magnetic copper. Among them, 106 is the conductive coil winding. The main magnetic flux generated by the conductive coil winding 106 reaches the magnetic thin film layer 105. Therefore, the thin film layer has an extremely high relative magnetic permeability. Therefore, the effective magnetic permeability of the magnetic circuit can be improved in the horizontal direction, and at the same time, the length of the magnetic circuit can be shortened in the vertical direction, thereby greatly increasing the inductance density of the magnetic device. At the same time, the patterning treatment of the magnetic thin film improves the resistivity of the magnetic thin film and can greatly reduce the eddy current loss caused by the magnetic flux inside the magnetic thin film.

[0065] Furthermore, since dielectric isolation is required between the thin film and the coil, the magnetic component further includes a dielectric layer. The dielectric layer is disposed between the magnetic thin film layer and the conductive coil winding to wrap and insulate the magnetic thin film and the conductive coil, thereby achieving isolation between the magnetic thin film and the conductive coil.

[0066] The above are only the preferred embodiments of the present invention. It should be noted that the above preferred embodiments should not be construed as limiting the present invention. For those of ordinary skill in the art, without departing from the spirit and scope of the present invention, several improvements and refinements can be made. The improvements and refinements to the micro-device should also be regarded as the protection scope of the present invention. Here, no more embodiments will be described in detail. The protection scope of the present invention should be subject to the scope defined by the claims.

Claims

1. A method for manufacturing a magnetic core, characterized in that, it includes the following steps: A first shielding layer coating step of coating a first shielding layer on the upper surface of a semiconductor substrate; A first groove opening step of opening a first groove vertically penetrating the first shielding layer on the first shielding layer, so that a first exposed area is formed on the semiconductor substrate; A first conductive layer setting step of setting a first conductive layer on the upper surface of the first shielding layer and the upper surface of the first exposed area, and then removing the first shielding layer and the first conductive layer on its upper surface, so that only the first conductive layer remains on the first groove, and a second exposed area is formed on the semiconductor substrate; A second shielding layer coating step of coating a second shielding layer on the upper surface of the first conductive layer and the upper surface of the second exposed area, and the second shielding layer is divided into a first part located on the upper surface of the first conductive layer and a second part located on the upper surface of the second exposed area; A second groove opening step of opening a second groove penetrating the second shielding layer above the first part of the second shielding layer, so that a third exposed area is formed on the first conductive layer; A magnetic thin film layer setting step of setting a magnetic thin film layer on the upper surface of the third exposed area; A second shielding layer removing step of removing the remaining second part in the second shielding layer.

2. The method for manufacturing a magnetic core according to claim 1, characterized in that: The thickness of the first shielding layer is greater than the thickness of the first conductive layer.

3. The method for manufacturing a magnetic core according to claim 1, characterized in that: The thickness of the second shielding layer is greater than the thickness of the magnetic thin film layer.

4. The method for manufacturing a magnetic core according to claim 1, characterized in that: The thickness of the first conductive layer is less than the thickness of the magnetic thin film layer.

5. The method for manufacturing a magnetic core according to claim 1, characterized in that: The sum of the projected areas of the magnetic thin film on the upper surface of the first conductive layer is less than the projected area of the first conductive layer on the upper surface of the semiconductor substrate.

6. The method for manufacturing a magnetic core according to claim 1, characterized in that: The material of the first conductive layer is nickel; or cobalt; or titanium; or any combination of two materials among nickel, cobalt, and titanium; or a combination of the three materials of nickel, cobalt, and titanium.

7. The method for manufacturing a magnetic core according to claim 1, characterized in that: The material of the magnetic thin film contains any combination of two materials among iron, cobalt, and nickel; or contains a combination of the three materials of iron, cobalt, and nickel.

8. A magnetic component, and the magnetic component is a on-chip magnetic component, characterized in that: It includes a magnetic core manufactured by the method for manufacturing a magnetic core according to any one of claims 1 to 7.

9. The magnetic component according to claim 8, characterized in that: The magnetic component further includes a conductive coil winding.

10. The magnetic component according to claim 9, characterized in that: The magnetic component further includes a dielectric layer, and the dielectric layer is arranged between the magnetic thin film layer and the conductive coil winding to wrap and insulate the magnetic thin film and the conductive coil winding.

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