Method for manufacturing a magnetic core and a magnetic component

Abstract

The application discloses a magnetic core manufacturing method and a magnetic component. The magnetic core manufacturing method comprises the following steps: coating a first shielding layer on the upper surface of a semiconductor substrate; opening a first groove vertically penetrating through the first shielding layer to form a first exposed area on the semiconductor substrate; arranging a first conductive layer on the upper surface of the first shielding layer and the first exposed area, and then removing the first shielding layer and the first conductive layer on the upper surface of the first shielding layer to form a second exposed area on the semiconductor substrate; coating a second shielding layer on the upper surface 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; opening a second groove penetrating through the second shielding layer on the first part of the second shielding layer to form a third exposed area on the first conductive layer; arranging a magnetic thin film layer on the upper surface of the third exposed area; and removing the second part of the second shielding layer. The application can avoid the defects of wet etching patterning.

Description

TECHNICAL FIELD

[0001] The present application relates to a magnetic device, in particular to a magnetic core manufacturing method and a device. BACKGROUND

[0002] At present, with the rapid development of semiconductor manufacturing technology, the application frequency of power semiconductor devices in module power supply is continuously increasing, and the loss is continuously decreasing; the two-dimensional planar structure of "thin film type" micro-magnetic device based on integrated circuit process manufacturing can replace the three-dimensional structure of magnetic device prepared by traditional manufacturing technology, which greatly reduces the volume of module power supply and conforms to the development trend of miniaturization and light weight of electronic products.

[0003] In modern technology, micro-magnetic devices (generally referred to as on-chip magnetic devices) manufactured using integrated processes can be roughly divided into two categories: air coils and micro-magnetic devices containing magnetic cores. Compared with air coils, micro-magnetic devices containing magnetic cores (i.e. magnetic on-chip magnetic devices) have better EMI effect, higher inductance density, and better magnetic coupling coefficient, and are more promising.

[0004] In the manufacturing process of integrated circuits, a modern magnetic thin film preparation scheme is to deposit a conductive seed layer on the surface of a single wafer substrate, and then form a magnetic thin film through electroplating, and then perform patterning and segmentation on the whole magnetic thin film wafer through dry etching or wet etching steps to remove the residual thick magnetic thin film metal in the wafer cutting channel to avoid affecting wafer cutting, or to reduce the eddy current loss of the metal magnetic thin film through patterning and segmentation. In this technology, the rate of dry etching is relatively low, and the manufacturing cost is relatively high; wet etching has isotropy, and the etching precision is not high, and metal residues are easily caused by incomplete etching. SUMMARY

[0005] In view of the deficiencies of the prior art described above, the technical problem to be solved by the present application is to provide a magnetic core manufacturing method and a magnetic device which at least to some extent can solve the deficiencies of the prior art described above.

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

[0007] A magnetic core manufacturing method, comprising the following steps:

[0008] A first shielding layer coating step is performed on the upper surface of the semiconductor substrate to coat a first shielding layer;

[0009] A first trench opening step is performed on the first shielding layer to open a first trench vertically through the first shielding layer, so that a first exposed area is formed on the semiconductor substrate;

[0010] The first conductive layer setting step sets a first conductive layer on the upper surface of the first shielding layer and the upper surface of the first exposed area, and then removes the first shielding layer and the first conductive layer on the upper surface of the first shielding layer, so that only the first conductive layer remains on the first trench, and a second exposed area is formed on the semiconductor substrate;

[0011] The second shielding layer coating step coats 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 on the upper surface of the first conductive layer and a second part on the upper surface of the second exposed area;

[0012] The second trench opening step opens a second trench through the second shielding layer on the first part of the second shielding layer, so that a third exposed area is formed on the first conductive layer;

[0013] The magnetic thin film layer setting step sets a magnetic thin film layer on the upper surface of the third exposed area;

[0014] The second shielding layer removing step removes the remaining second part of the second shielding layer.

[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 two of nickel, cobalt, and titanium; or a combination of nickel, cobalt, and titanium.

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

[0021] As a second aspect of the present application, the technical solutions of the embodiments of the magnetic component are as follows:

[0022] A magnetic component, which is an on-chip magnetic component, wherein: it comprises a magnetic core manufactured by the magnetic core manufacturing method of any one of the first aspect.

[0023] Further, the magnetic component further comprises a conductive coil winding.

[0024] Further, the magnetic member further comprises a medium layer, which is arranged between the magnetic thin film layer and the conductive coil winding, and insulates the magnetic thin film and the conductive coil winding.

[0025] The present application has the beneficial effect that the deposition method of the conductive seed layer and the magnetic thin film is optimized, the first shielding layer coating step, the first groove opening step and the first conductive layer setting step are used to manufacture the patterned first conductive layer, and then the second shielding layer coating step, the second groove opening step and the magnetic thin film layer setting step are used to deposit the magnetic thin film layer on the patterned first conductive layer, so that the method of using the patterned first conductive layer to prepare the magnetic thin film layer can avoid the problems of low dry etching rate and patterned defects of the magnetic thin film layer caused by wet etching. BRIEF DESCRIPTION OF DRAWINGS

[0026] Figure 1 Flow chart of the magnetic core manufacturing method of the first embodiment of the present application;

[0027] Figure 2 Partial structure diagram of the intermediate product of the magnetic core manufacturing method of the first embodiment of the present application along the vertical direction of the semiconductor substrate;

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

[0029] Figure 4 Specific structure diagram of the magnetic member of the second embodiment of the present application;

[0030] Among them, the symbols are as follows:

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

[0032] The technical solutions in the present application will be described clearly and completely in combination with the drawings. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0033] In the description of the present application, it should be noted that the terms "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer" and the like indicate the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application. In addition, the terms "first", "second", "third", "step 1", "step 2" and the like are only for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0034] In addition, the technical features involved in the different embodiments of the present application described below can be combined with each other as long as there is no conflict.

[0035] First embodiment

[0036] A magnetic core manufacturing method, Figure 1 A flowchart of the magnetic core manufacturing method of the first embodiment of the present application, Figure 2 A schematic diagram of the partial structure of the intermediate product of the magnetic core manufacturing method of the first embodiment of the present application along the vertical direction of the semiconductor substrate, Figures 3a to 3i is Figure 2 A schematic diagram of the corresponding structure along the horizontal direction of the semiconductor substrate, see Figure 1 The magnetic core manufacturing method of the present embodiment includes the following steps:

[0037] S100, a first shielding layer coating step, coating a first shielding layer 102 on the upper surface of a semiconductor substrate 101, see Figure 2 , wherein S1 is a schematic diagram of the structure of the semiconductor substrate 101, and S2 is a schematic diagram of the structure of the intermediate product after this step, Figure 3a is Figure 2 a schematic diagram of S1 in Figure 3b is Figure 2 a schematic diagram of S2 in

[0038] The semiconductor substrate 101 of the present embodiment can be selected from pure semiconductor material substrates such as silicon substrates, sapphire substrates, or compound substrates, etc., in which case the surface material of the semiconductor substrate is silicon, sapphire, or a compound. It can also be a substrate on which other materials have been deposited, such as a substrate on which PI has been spin-coated, in which case the surface of the substrate is PI. The present application does not limit the specific choice of semiconductor substrate, and those skilled in the art can make the selection as needed.

[0039] Specifically, the first shielding layer 102 can be uniformly coated on the upper surface of the semiconductor substrate 101 by spin coating, spraying, dipping, etc. using a photoresist material (i.e. photoresist), and completely covers the upper surface of the semiconductor substrate 101. Then, the first shielding layer 102 needs to be pre-baked by a hot plate. The baking conditions are set in combination with the requirements of the photoresist material and the thickness of the first shielding layer 102. In combination with the present method, a negative photoresist is preferably used. The thickness of the photoresist used as the first shielding layer is generally set to be greater than or equal to 3 um.

[0040] S200, a first trench opening step, a first trench vertically penetrating the first shielding layer 102 is opened on the first shielding layer 102, so that a first exposed area is formed on the semiconductor substrate 101. Please refer to Figure 2 S3 in FIG. 1 is a schematic diagram of the intermediate product after the first trench opening step is completed, Figure 3c S3 in FIG. 1 is a schematic diagram of the intermediate product after the first trench opening step is completed, Figure 2 S3 in FIG. 1 is a schematic diagram of the intermediate product after the first trench opening step is completed,

[0041] Specifically, the first shielding layer 102 can be uniformly coated on the upper surface of the semiconductor substrate 101 by spin coating, spraying, dipping, etc. using a photoresist material (i.e. photoresist), and completely covers the upper surface of the semiconductor substrate 101. Then, the first shielding layer 102 needs to be pre-baked by a hot plate. The baking conditions are set in combination with the requirements of the photoresist material and the thickness of the first shielding layer 102. In combination with the present method, a negative photoresist is preferably used. The thickness of the photoresist used as the first shielding layer is generally set to be greater than or equal to 3 um.

[0042] S300, a first conductive layer setting step, a first conductive layer 103 is set on the upper surface of the first shielding layer and the upper surface of the first exposed area. Please refer to Figure 2 S4 in FIG. 2 is a schematic diagram of the intermediate product after the first conductive layer setting step is completed, Figure 3d S4 in FIG. 2 is a schematic diagram of the intermediate product after the first conductive layer setting step is completed, Figure 2 S4 in FIG. 2 is a schematic diagram of the intermediate product after the first conductive layer setting step is completed, Figure 2 S5 in FIG. 3 is a schematic diagram of the intermediate product after the first conductive layer removing step is completed, Figure 3e S5 in FIG. 3 is a schematic diagram of the intermediate product after the first conductive layer removing step is completed, Figure 2 S5 in FIG. 3 is a schematic diagram of the intermediate product after the first conductive layer removing step is completed,

[0043] Specifically, the first conductive layer 103 can be deposited by sputtering, CVD or PECVD, evaporation, etc. The first conductive layer deposited by sputtering, CVD or PECVD, or evaporation will be attached to the upper surface of the first shielding layer and the upper surface of the first exposed area. Preferably, the thickness of the first conductive layer deposited should be less than or equal to one-third of the thickness of the first shielding layer, so as to avoid the deposition of the conductive layer on the sidewall of the first trench, which will cause the conductive layer on the upper surface of the first exposed area to be connected to the conductive layer on the upper surface of the first shielding layer 102 through the conductive layer on the sidewall of the first trench, thereby affecting the removal effect of the first shielding layer.

[0044] The first shielding layer and the first conductive layer on its upper surface can be removed by a stripping process, which generally uses a photoresist stripping solution. The first shielding layer 102 will dissolve and fall off during the stripping solution immersion process, and at the same time, the first conductive layer on the upper surface of the first shielding layer 102 will also be removed 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, a second shielding layer 104 is coated 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 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. Please refer to Figure 2 S6 in FIG. 6 is a structural schematic diagram of the intermediate product after this step, Figure 3f S6 in FIG. 6 is a structural schematic diagram of the intermediate product after this step, Figure 2 S6 in FIG. 6 is a structural schematic diagram of the intermediate product after this step,

[0046] Specifically, a photoresist material (photoresist) can be uniformly coated on the upper surface of the first conductive layer 103 and the upper surface of the exposed semiconductor substrate 101 by spin coating, spraying, dipping, etc. This step also preferably uses a negative photoresist. The thickness of the photoresist used as the second shielding layer 104 is generally set to be more than twice the required magnetic thin film thickness.

[0047] S500, a second trench opening step, a second trench is opened on the first part of the second shielding layer, which penetrates the second shielding layer, so that a third exposed area is formed on the first conductive layer. Please refer to Figure 2 S7 in FIG. 7 is a structural schematic diagram of the intermediate product after this step, Figure 3g S7 in FIG. 7 is a structural schematic diagram of the intermediate product after this step, Figure 2 S7 in FIG. 7 is a structural schematic diagram of the intermediate product after this step,

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

[0049] S600, the magnetic thin film layer 105 setting step, setting the magnetic thin film layer 105 on the upper surface of the third exposed area, please see Figure 2 S8 in the figure is the structure diagram of the intermediate product after this step, Figure 3h S8 in the figure is the structure diagram of the intermediate product after this step, Figure 2 S8 in the figure is the structure diagram of the intermediate product after this step,

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

[0051] S700, the second shielding layer removing step, removing the remaining second part of the second shielding layer, please see Figure 2 S9 in the figure is the structure diagram of the intermediate product after this step, Figure 3i S9 in the figure is the structure diagram of the intermediate product after this step, Figure 2 S9 in the figure is the structure diagram of the intermediate product after this step,

[0052] This step is the same as the method of removing the first shielding layer and the first conductive layer on the upper surface of the first shielding layer in the S300 step. The remaining second shielding layer is removed by the adhesive remover.

[0053] The magnetic core manufactured by the method of the embodiment does not have the steps of dry etching or wet etching. Therefore, after the S700 step of removing the second shielding layer is completed and the wafer slicing and cutting of the magnetic component are completed, a part of the cutting surface of the first conductive seed layer is exposed on the sidewall of the single magnetic component wafer, that is, Figure 4 the cutting surface of the first conductive seed layer 103 in the figure, so that whether the method is used can be determined by observing whether the cutting surface of the first conductive seed layer exists on the sidewall of the wafer.

[0054] In the magnetic core manufacturing method of the embodiment, the first conductive layer and the magnetic thin film layer are not prepared by the method of patterning and etching the whole wafer first, but by the first shielding layer coating step, the first groove opening step and the first conductive layer setting step to manufacture the patterned first conductive layer, and then by the second shielding layer coating step, the second groove opening step and the magnetic thin film layer setting step to set the magnetic thin film layer only 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 patterning defects of the magnetic thin film layer caused by wet etching in the prior art.

[0055] Preferably, the first shielding layer thickness is greater than the first conductive layer thickness to avoid the first conductive layer covering the first shielding layer entirely and affecting the removal of the first shielding layer.

[0056] Preferably, the second shielding layer thickness is greater than the magnetic thin film layer thickness to avoid the magnetic thin film layer being connected in a piece on the top of the second shielding layer and failing to form a patterning effect.

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

[0058] Preferably, the sum of the magnetic thin film projection areas on the first conductive layer upper surface is less than the projection area of the first conductive layer on the semiconductor substrate upper surface, so that the wafer is not cut to damage the magnetic thin film when the wafer is diced.

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

[0060] Preferably, the magnetic thin film material comprises any two material combinations of iron, cobalt, and nickel, or a combination of the three materials of iron, cobalt, and nickel.

[0061] Second embodiment

[0062] The embodiment provided is a magnetic component, which is an on-chip magnetic component, wherein: the magnetic component comprises a magnetic core manufactured by any one of the magnetic core manufacturing methods of the first embodiment.

[0063] Further, the magnetic component further comprises a conductive coil winding, wherein the conductive coil winding pattern can adopt a planar spiral coil structure or a solenoid coil structure; the position of the conductive coil winding, and the layer number setting and position setting of each layer when the planar spiral coil structure is designed are not limited by the present application, and can be selected by those skilled in the art as needed.

[0064] Figure 4 A specific structure diagram of the magnetic component of the second embodiment of the present application is a magnetic copper-coated planar spiral coil winding structure, wherein 106 is the conductive coil winding. The main magnetic flux generated by the conductive coil winding 106 reaches the magnetic thin film layer 105, so the thin film layer has a very high relative permeability, and thus the effective permeability of the magnetic circuit in the horizontal direction can be improved, and the magnetic circuit length in the vertical direction can be shortened, thereby greatly improving the inductance density of the magnetic component. At the same time, the patterning processing 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 in the magnetic thin film.

[0065] Further, the medium needs to be isolated between the thin film and the coil, and the magnetic component further comprises a medium layer arranged between the magnetic thin film layer and the conductive coil winding, which insulates the magnetic thin film and the conductive coil, and realizes the isolation between the magnetic thin film and the conductive coil.

[0066] The above is only the preferred embodiment of the present application, and it should be noted that the above preferred embodiment should not be regarded as a limitation of the present application, and for those skilled in the art, several improvements and refinements can be made without departing from the spirit and scope of the present application, and the improvement and refinement of the micro device should also be regarded as the protection scope of the present application, which will not be described in detail here, and the protection scope of the present application should be limited by the scope defined in the claims.

Claims

1. A method for manufacturing a magnetic core, characterized in that, Includes the following steps: The first shielding layer coating step involves coating a first shielding layer on the upper surface of a semiconductor substrate; In the first trench forming step, a first trench is formed vertically through the first shielding layer, thereby forming a first exposed area on the semiconductor substrate. The first conductive layer setting step involves 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 trench, and a second exposed area is formed on the semiconductor substrate, thereby obtaining a patterned first conductive layer. The second shielding layer coating step involves coating a second shielding layer 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. In the second trench opening step, a second trench penetrating the second shielding layer is opened on the first part of the second shielding layer, so that the part of the first conductive layer that needs to be provided with a magnetic thin film layer forms a third exposed area, and the remaining second part of the second shielding layer shields the area that does not need to be provided with a magnetic thin film layer but needs to be conductive. The magnetic thin film layer setting step involves setting a magnetic thin film layer on the upper surface of the third exposed area formed within the channel-shaped groove of the second trench; The second shielding layer removal step removes the remaining second portion of the second shielding layer, thereby forming a magnetic core by setting a magnetic thin film layer only on the patterned first conductive layer, and the magnetic thin film layer is directly patterned on the upper surface of the first conductive 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 layers on the surface of the first conductive layer is less than the projected area of ​​the first conductive layer on the surface of the semiconductor substrate.

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

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

8. A magnetic component, wherein the magnetic component is an on-chip magnetic component, characterized in that: The magnetic core manufactured by any one of the magnetic core manufacturing methods according to claims 1 to 7.

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

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

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