Coupled inductor and method of making the same

Abstract

A coupled inductor has two coils made by a photolithography process, wherein a first coil is disposed on an upper surface of a magnetic sheet and a second coil is disposed on a lower surface of the magnetic sheet to control a gap variation between the two coils within a small range.

Description

[0001] This application is a divisional application. The original application was filed on April 28, 2022, with application number 202210470321.2, and the invention title was "Coupled Inductor and Method for Manufacturing the Same". Technical Field

[0002] This invention relates to a coupling inductor, and more particularly to a coupling inductor manufactured using a coating process or a photolithography process. Background Technology

[0003] Traditional coupled inductors consist of two coils made of two discrete wires. However, the gap between the two coils of a traditional coupled inductor varies over a wide range, which affects the reliability and performance of the coupled inductor.

[0004] Furthermore, traditional coupled inductors use a first mold, such as FIG. 1A As shown, the second mold is as follows FIG. 1B As shown, the first coil C1 surrounds the central pillar P1, and the second coil C2 surrounds the central pillar P2. Therefore, the deviation of the pillar center can be the sum of the first mold deviation and the second mold deviation plus the combined process deviation. In addition, each traditional coupled inductor is manufactured individually, so the deviation of the pillar center has a Gaussian distribution with a large range of variation, which is not conducive to maintaining the reliability and performance of the product.

[0005] In addition, such as FIG. 1C and FIG. 1D As shown, the gap between the second coil C2 and the first coil C1 can vary within a wide range of 0-76µm, which is not conducive to maintaining the reliability and performance of the product.

[0006] Therefore, a better solution is needed to address the above problems. Summary of the Invention

[0007] The purpose of this invention is to provide a coupled inductor having two coils, which are manufactured using a coating process or a photolithography process, for controlling the variation in the gap between the two coils within a small range.

[0008] The purpose of this invention is to provide a method for manufacturing multiple coupled inductors in a single process, wherein the multiple coupled inductors manufactured by a coating process or a photolithography process can control the variation of the gap between two coils within a smaller range to maintain the reliability and performance of the product. In this invention, the standard deviation of the K (coupling coefficient) value of all finished products produced in batches is significantly reduced.

[0009] An embodiment of the present invention discloses a coupled inductor comprising: a first coil structure including at least one first conductive layer, wherein each conductive layer is formed on a corresponding insulating layer, wherein the at least one first conductive layer includes a first conductive pattern for forming at least one first winding of a first coil; a second coil structure including at least one second conductive layer, wherein each conductive layer is formed on a corresponding insulating layer, wherein the at least one second conductive layer includes a second conductive pattern for forming at least one second winding of a second coil; and wherein, in a first hollow space spanning the at least one first winding of the first coil structure, the at least one first winding of the first coil structure, and the second coil... On a first vertical plane of a second hollow space of at least one second winding of the structure and at least one second winding of the second coil structure, a first horizontal distance between the midpoint of a first horizontal line segment and the midpoint of a second horizontal line segment is not greater than 1 μm, wherein the first horizontal line segment extends from a first innermost edge of the first winding of the first coil through the first hollow space to a second innermost edge of the first winding of the first coil, and the second horizontal line segment extends from a third innermost edge of the second winding of the second coil through the second hollow space to a fourth innermost edge of the second winding of the second coil.

[0010] In one embodiment of the present invention, a magnetic sheet is further included, wherein the first coil structure is disposed above the upper surface of the magnetic sheet, and the second coil structure is disposed below the lower surface of the magnetic sheet.

[0011] In one embodiment of the present invention, on a second vertical plane spanning at least one first winding of the first coil structure, a first hollow space of the at least one first winding of the first coil structure, at least one second winding of the second coil structure, and a second hollow space of the at least one second winding of the second coil structure, a second horizontal distance between the midpoint of a third horizontal line segment and the midpoint of a fourth horizontal line segment is not greater than 1 μm, wherein the third horizontal line segment extends from a fifth innermost edge of the first winding of the first coil through the first hollow space to a sixth innermost edge of the first winding of the first coil, and the second horizontal line segment extends from a seventh innermost edge of the second winding of the second coil through the second hollow space to an eighth innermost edge of the second winding of the second coil, wherein the second vertical plane is perpendicular to the first vertical plane.

[0012] In one embodiment of the present invention, a first magnetic body and a second magnetic body are further included, wherein the first magnetic body is disposed on the upper surface of the magnetic sheet to cover at least one first winding of the first coil, and the second magnetic body is disposed on the lower surface of the magnetic sheet to cover at least one second winding of the second coil.

[0013] In one embodiment of the present invention, the at least one first conductive layer includes a first plurality of conductive layers, wherein each of the first plurality of conductive layers is sequentially formed on a corresponding insulating layer starting from a first bottom insulating layer, wherein the first plurality of conductive layers is located between the first bottom insulating layer and a first top insulating layer, wherein the first bottom insulating layer is in contact with the upper surface of the magnetic sheet.

[0014] In one embodiment of the present invention, the at least one second conductive layer includes a second plurality of conductive layers, wherein each of the second plurality of conductive layers is sequentially formed on a corresponding insulating layer starting from a second bottom insulating layer, wherein the second plurality of conductive layers is located between the second bottom insulating layer and a second top insulating layer, wherein the second bottom insulating layer is in contact with the lower surface of the magnetic sheet.

[0015] In one embodiment of the present invention, the at least one second conductive layer includes a second plurality of conductive layers, wherein each of the second plurality of conductive layers is sequentially formed on a corresponding insulating layer starting from a second bottom insulating layer, wherein the second plurality of conductive layers is located between the second bottom insulating layer and a second top insulating layer, wherein the second top insulating layer is in contact with the lower surface of the magnetic sheet.

[0016] In one embodiment of the present invention, the first magnetic body includes a first single magnetic body that covers at least one first winding of the first coil and extends into a first hollow portion of the first coil.

[0017] In one embodiment of the present invention, the second magnetic body includes a second single magnetic body that covers at least one second winding of the second coil and extends into a second hollow portion of the first coil.

[0018] In one embodiment of the present invention, the first winding is formed on the first bottom insulating layer, wherein a corresponding insulating layer is formed on the first conductive layer containing the first winding, the corresponding insulating layer covering the first winding and extending to an unpatterned area of ​​the first conductive layer.

[0019] In one embodiment of the present invention, the at least one first conductive layer is formed by a coating process.

[0020] In one embodiment of the present invention, the first magnetic body is formed of a first material, and the magnetic sheet is formed of a second material different from the first material.

[0021] In one embodiment of the present invention, both the first magnetic body and the second magnetic body are formed of a first material, and the magnetic sheet is formed of a second material different from the first material.

[0022] In one embodiment of the present invention, the first magnetic body is formed of a first material, the magnetic sheet is formed of a second material, and the second magnetic body is formed of a third material, wherein the first material, the second material, and the third material are all different from each other.

[0023] An embodiment of the present invention discloses a coupling inductor comprising: a first coil structure including at least one first conductive layer, wherein each conductive layer is formed on a corresponding insulating layer, wherein the at least one first conductive layer includes a first conductive pattern for forming at least one first winding of a first coil;

[0024] A second coil structure includes at least one second conductive layer, wherein each conductive layer is formed on a corresponding insulating layer, wherein the at least one second conductive layer includes a second conductive pattern for forming at least one second winding of a second coil; and wherein at least one first winding of the first coil structure and at least one second winding of the second coil structure are stacked in a vertical direction, wherein the first coil structure and the second coil structure are formed according to the same composition image pattern, wherein the relative position of the axis of the first coil to the shape of the first coil is the same as the relative position of the axis of the first coil to the axis of the second coil relative to the shape of the second coil.

[0025] In one embodiment of the present invention, a magnetic sheet is further included, wherein the first coil structure is disposed above the upper surface of the magnetic sheet, and the second coil structure is disposed below the lower surface of the magnetic sheet.

[0026] In one embodiment of the present invention, a first magnetic body and a second magnetic body are further included, wherein the first magnetic body is disposed on the upper surface of the magnetic sheet to cover at least one first winding of the first coil, and the second magnetic body is disposed on the lower surface of the magnetic sheet to cover at least one second winding of the second coil.

[0027] In one embodiment of the present invention, each of at least one second conductive layer is formed by a coating process.

[0028] In one embodiment of the present invention, each of at least one second conductive layer is formed by an electroplating process.

[0029] In one embodiment of the present invention, each of at least one second conductive layer is formed by a thin film process.

[0030] In one embodiment of the present invention, each of at least one second conductive layer is formed by a thick film process.

[0031] To make the above and other features and advantages of the present invention clearer, several embodiments will be described in detail below with reference to the accompanying drawings. Attached Figure Description

[0032] The foregoing description of the present invention and its accompanying advantages will be more fully understood by referring to the following detailed description and in conjunction with the drawings, wherein:

[0033] FIGS. 1A-1D Partial views of a conventional coupled inductor are shown.

[0034] FIG. 2A A schematic diagram of a coupled inductor according to an embodiment of the present invention is shown.

[0035] FIG. 2B A coil structure formed on a carrier according to an embodiment of the present invention is shown.

[0036] FIGS. 2C-2D A schematic diagram of the coil structure after removing the carrier is shown in one embodiment of the present invention.

[0037] FIG. 2E A perspective view of a coupled inductor according to an embodiment of the present invention is shown.

[0038] FIGS. 3A-3B Methods for forming a coupled inductor according to an embodiment of the present invention are shown respectively.

[0039] FIG. 4A An embodiment of the present invention is shown for forming a stack of multiple coupled inductors.

[0040] FIG. 4B The illustration shows an arrangement of sheets for forming a plurality of coupled inductors according to an embodiment of the present invention.

[0041] FIG. 5 A method for forming a coupled inductor according to an embodiment of the present invention is shown.

[0042] FIG. 6 The graph shows the effect of the positional alignment difference of the two coils of a coupled inductor on its coupling coefficient and mutual inductance.

[0043] FIGS. 7A-7D Partial cross-sectional views of a coupled inductor according to an embodiment of the present invention are shown.

[0044] Explanation of reference numerals in the attached diagram: C1 - coil; P1 - center post; C2 - coil; P2 - center post; 100 - coupled inductor; 101 - first coil structure; 101c, 101d - first conductive layer; 101b, 101e - insulating layer; 102 - second coil structure; 102c, 102d - second conductive layer; 102b, 102e - insulating layer; 103 - magnetic sheet; 101h - first hollow part; 102h - second hollow part Empty section; 101L - Insulating layer; 102L - Insulating layer; 101U - Insulating layer; 102U - Insulating layer; E1 - First electrode; E2 - Second electrode; E3 - Third electrode; E4 - Fourth electrode; 104 - First magnetic body; 105 - Second magnetic body; 200 - First carrier; 401 - First sheet; 403 - Third magnetic sheet; 402 - Second sheet; 404 - Fourth magnetic sheet; 405 - Fifth magnetic sheet; 500 - CCD Detailed Implementation

[0045] The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0046] The present invention discloses a coupled inductor comprising: a first coil formed by a thin film process, the first coil including at least a first winding; and a second coil formed by a coating process, wherein the second coil includes at least a second winding, and wherein the gap between the lower surface of the first coil and the upper surface of the second coil can be minimized by the coating process.

[0047] There are many ways to form the coupled inductor structure of the present invention, which will be described one by one below.

[0048] FIG. 2A A view of a coupled inductor according to an embodiment of the present invention is shown. FIG. 2AAs shown, the coupled inductor 100 includes: a first coil structure 101, including at least one first conductive layer 101c, 101d, wherein each conductive layer 101c, 101d is formed on a corresponding insulating layer 101b, 101e, wherein the at least one first conductive layer 101c, 101d includes a first conductive pattern for forming at least one first winding of a first coil; and a second coil structure 102 including at least one second conductive layer 102c, 102d, wherein each conductive layer 102c, 102d is formed on a corresponding insulating layer 102b, 101e. e, wherein at least one second conductive layer 102c, 102d includes at least one second winding for forming a second coil; magnetic sheet 103, wherein a first coil structure 101 is disposed on the upper surface of the magnetic sheet 103, and a second coil structure 102 is disposed on the lower surface of the magnetic sheet 103, wherein the first coil structure 101 and the second coil structure 102 are located on opposite sides of the magnetic sheet 103, wherein a straight line passes through the first hollow portion 101h of the at least one first winding of the first coil and the second hollow portion 102h of the at least one second winding of the second coil.

[0049] In one embodiment, the outer surface of at least one of the first conductive layers 101c, 101d is covered by an insulating layer 101L.

[0050] In one embodiment, the outer surface of at least one of the second conductive layers 102c, 102d is covered by an insulating layer 102L.

[0051] In one embodiment, the inner surface of at least one of the first conductive layers 101c, 101d is covered by an insulating layer 101U.

[0052] In one embodiment, the inner surface of at least one of the second conductive layers 102c, 102d is covered by an insulating layer 102U.

[0053] In one embodiment, the first electrode E1 and the second electrode E2 of the coupled inductor are electrically connected to the first coil, and the third electrode E3 and the fourth electrode E4 of the coupled inductor are electrically connected to the second coil, such as... FIG. 2E As shown.

[0054] In one embodiment, a vertical line passes through a first hollow portion 101h of at least one first winding of a first coil and a second hollow portion 102h of at least one second winding of a second coil.

[0055] In one embodiment, the coupled inductor 100 includes: a first magnetic body 104, wherein the first magnetic body 104 is disposed on the upper surface of the magnetic sheet 103 to cover at least one first winding of a first coil; and a second magnetic body 105, wherein the second magnetic body 105 is disposed on the lower surface of the magnetic sheet 103 to cover at least one second winding of a second coil.

[0056] In one embodiment, the first electrode E1 and the second electrode E2 of the coupled inductor are electrically connected to the first coil, and the third electrode E3 and the fourth electrode E4 of the coupled inductor are electrically connected to the second coil. The first electrode E1, the second electrode E2, the third electrode E3, and the fourth electrode E4 are disposed on the lower surface of the second magnetic body 105. FIG. 2E As shown.

[0057] In one embodiment, the first and second electrodes of the coupling inductor are electrically connected to the first coil, and the third and fourth electrodes of the coupling inductor are electrically connected to the second coil, wherein the first, second, third, and fourth electrodes are disposed on the upper surface of the first magnetic body 104.

[0058] In one embodiment, at least one first conductive layer 101c, 101d includes a first plurality of conductive layers 101c, 101d, wherein each of the first plurality of conductive layers 101c, 101d is sequentially formed on a corresponding insulating layer 101b, 101e and starts from a first bottom insulating layer 101b, wherein the first bottom insulating layer 101b is in contact with the upper surface of the magnetic sheet.

[0059] In one embodiment, a first bottom insulating layer 101b is first formed on the carrier, and a first plurality of conductive layers 101c and 101d are formed on the first bottom insulating layer 101b. The carrier is removed after the first coil structure 101 is formed.

[0060] In one embodiment, at least one first conductive layer 101c, 101d includes a first plurality of conductive layers 101c, 101d, wherein each of the first plurality of conductive layers 101c, 101d is sequentially formed on a corresponding insulating layer 101b, 101e and starts from a first bottom insulating layer 101b, wherein the first bottom insulating layer 101b is in contact with the upper surface of the magnetic sheet 103.

[0061] In one embodiment, a first bottom insulating layer 101b is first formed on the carrier, and a first plurality of conductive layers 101c and 101d are formed on the first bottom insulating layer 101b. The carrier is removed after the first coil structure 101 is formed.

[0062] In one embodiment, a first plurality of conductive layers are located between a first bottom insulating layer 101b and a first top insulating layer 101a, wherein the first bottom insulating layer 101b is in contact with the upper surface of the magnetic sheet 103.

[0063] In one embodiment, at least one second conductive layer 201c, 201d includes a second plurality of conductive layers 201c, 201d, wherein each of the second plurality of conductive layers 201c, 201d is sequentially formed on a corresponding insulating layer 201b, 201e and starts from a second bottom insulating layer 201b, wherein the second bottom insulating layer 201b is in contact with the upper surface of the magnetic sheet 103.

[0064] In one embodiment, a second bottom insulating layer 201b is first formed on a carrier, a second plurality of conductive layers 201c, 201d are formed above the second bottom insulating layer 201b, and the carrier is removed after the second coil structure 102 is formed.

[0065] In one embodiment, a second plurality of conductive layers are located between a second bottom insulating layer and a second top insulating layer, wherein the second bottom insulating layer is in contact with the lower surface of the magnetic sheet 103.

[0066] In one embodiment, the first magnetic body 104 includes a first single magnetic body that covers at least one first winding of the first coil and extends into a first hollow portion of the first coil.

[0067] In one embodiment, the second magnetic body 105 includes a second single magnetic body that covers at least one second winding of the second coil and extends into a second hollow portion of the second coil.

[0068] In one embodiment, a first winding is formed on a first bottom insulating layer, wherein a corresponding insulating layer is formed on a first conductive layer containing the first winding, wherein the corresponding insulating layer covers the first winding and extends into an unpatterned area of ​​the first conductive layer.

[0069] In one embodiment, a second winding is formed on a second bottom insulating layer, wherein a corresponding insulating layer is formed on a second conductive layer containing the second winding, wherein the corresponding insulating layer covers the second winding and extends into an unpatterned area of ​​the second conductive layer.

[0070] In one embodiment, the first coil is formed from a first plurality of conductive layers by a thin-film process, wherein a first winding of the first coil is formed on a first insulating layer, wherein a third insulating layer is formed on the first winding, and a third winding is formed on the third insulating layer, wherein a fifth insulating layer is formed on the upper surface of the first coil, and wherein the first insulating layer is in contact with the upper surface of the magnetic sheet.

[0071] In one embodiment, the first insulating layer may be formed on the first carrier 200, such as FIG. 2B As shown, after forming a first coil structure 101, the first carrier 200 is removed, as follows: FIG. 2C As shown, a hollow portion 101h of the first coil is formed.

[0072] In one embodiment, the second coil is formed by a second plurality of conductive layers through a coating process, wherein a second winding is formed on a second insulating layer, wherein a fourth insulating layer is formed on the second winding, the fourth winding is formed on the fourth insulating layer, wherein a sixth insulating layer is formed on the upper surface of the second coil, and wherein the second insulating layer is in contact with the lower surface of the magnetic sheet.

[0073] In one embodiment, the second insulating layer may be formed on the second carrier; after forming a second coil structure 102, the second carrier is removed, such as... FIG. 2D As shown, a hollow portion 102h of a second coil is formed.

[0074] In one embodiment, each of at least one first conductive layer is formed by a thin-film process.

[0075] In one embodiment, each of at least one first conductive layer is formed by a thick film process.

[0076] In one embodiment, the first magnetic body is formed of a first material, and the magnetic sheet is formed of a second material different from the first material.

[0077] In one embodiment, both the first magnetic body and the magnetic sheet are formed of a first material.

[0078] In one embodiment, both the first magnetic body and the second magnetic body are formed of a first material, and the magnetic sheet is formed of a second material different from the first material.

[0079] In one embodiment, the first magnetic body is formed of a first material, the magnetic sheet is formed of a second material, and the second magnetic body is formed of a third material, wherein the first material, the second material, and the third material are different from each other.

[0080] In one embodiment, such as FIG. 3AAs shown, the present invention discloses a method for forming a coupled inductor, the method comprising: step 201: forming a first coil structure on a carrier, wherein the first coil structure includes at least one first conductive layer, wherein each conductive layer is formed on a corresponding insulating layer, wherein the at least one first conductive layer includes a first conductive pattern for forming at least one first winding of a first coil; step 202: forming a second coil structure on the carrier, wherein the second coil structure includes at least one second conductive layer, each conductive layer is formed on a corresponding insulating layer, wherein the at least one second conductive layer includes a second conductive pattern for forming at least one second winding of a second coil; step 203: removing the carrier to obtain a first coil structure including a first insulating layer and a first coil formed on the first insulating layer and a second coil structure including a second insulating layer and a second coil formed on the second insulating layer; step 204: disposing the first coil structure on the upper surface of a magnetic sheet and disposing the second coil structure on the lower surface of the magnetic sheet.

[0081] In one embodiment, a vertical line passes through a first hollow portion of at least one first winding of a first coil and a second hollow portion of at least one second winding of a second coil.

[0082] In one embodiment, each of at least one first conductive layer is formed by a coating process.

[0083] In one embodiment, each of at least one first conductive layer is a metal layer formed by a thin-film process.

[0084] In one embodiment, each of at least one first conductive layer is formed by a thick film process.

[0085] In one embodiment, each of at least one first conductive layer is formed by an electroplating process.

[0086] In one embodiment, the method further includes disposing a first magnetic body on the upper surface of a magnetic sheet to cover at least one first winding of a first coil and extend into a first hollow portion of the first coil.

[0087] In one embodiment, the method further includes disposing a second magnetic body on the lower surface of the magnetic sheet to cover at least one second winding of the second coil and extend into a second space of the second coil.

[0088] In one embodiment, the first magnetic body is formed of a first material, and the magnetic sheet is formed of a second material different from the first material.

[0089] In one embodiment, each of the first magnetic body and the magnetic sheet is formed of a first material.

[0090] In one embodiment, each of the first magnetic body and the second magnetic body is formed of a first material, and the magnetic sheet is formed of a second material different from the first material.

[0091] In one embodiment, the first magnetic body is formed of a first material, the magnetic sheet is formed of a second material, and the second magnetic body is formed of a third material, wherein the first material, the second material, and the third material are different from each other.

[0092] In one embodiment, the first insulating layer is in contact with the upper surface of the magnetic sheet, and the second insulating layer is in contact with the lower surface of the magnetic sheet.

[0093] In one embodiment, the first coil is formed of a first plurality of conductive layers, wherein a first winding is formed on a first insulating layer disposed on a carrier, wherein a third insulating layer is formed on the first winding, wherein the first insulating layer is in contact with the upper surface of the magnetic sheet.

[0094] In one embodiment, the second coil is formed of a second plurality of conductive layers, wherein a second winding is formed on a second insulating layer disposed on a carrier, wherein a fourth insulating layer is formed on the first winding, and wherein the second insulating layer is in contact with the lower surface of the magnetic sheet.

[0095] In one embodiment, the first coil is formed of a first plurality of conductive layers, wherein a first winding is formed on a first insulating layer, wherein a third insulating layer is formed on the first winding and the third winding turns are formed on the third insulating layer, wherein a fifth insulating layer is formed on the upper surface of the first coil, and wherein the first insulating layer is in contact with the upper surface of the magnetic sheet.

[0096] In one embodiment, such as FIG. 3B As shown, this invention discloses a method for forming multiple coupled inductors, the method comprising: step 301: forming a first insulating layer on a first carrier, and forming at least one first conductive layer above the first insulating layer, wherein the at least one first conductive layer includes a first conductive pattern for forming multiple first coils; step 302: removing the first carrier to obtain a first sheet including the first insulating layer and multiple first coils; step 303: forming a second insulating layer on a second carrier, and forming at least one second conductive layer on the second insulating layer, wherein the at least one second conductive layer includes a second conductive pattern for forming multiple second coils; step 304: removing the second carrier to obtain a second sheet including the second insulating layer and multiple second coils; step 305: disposing the first sheet on the upper surface of a third magnetic sheet including a magnetic material, and disposing the second sheet on the lower surface of the third magnetic sheet.

[0097] like FIG. 4A As shown, the first sheet 401 is disposed on the upper surface of the third magnetic sheet 403, and the second sheet 402 is disposed on the lower surface of the third magnetic sheet 403.

[0098] In one embodiment, the method includes disposing a fourth magnetic sheet 404 comprising a magnetic material on the upper surface of the first sheet 401. For example... FIG. 4A As shown, the fourth magnetic sheet 404 is disposed on the upper surface of the first sheet 401.

[0099] In one embodiment, the method includes disposing a fifth magnetic sheet 405 comprising magnetic material on the lower surface of the second sheet 402. For example... FIG. 4A As shown, the fifth magnetic sheet 405 is disposed on the lower surface of the second sheet 402.

[0100] In one embodiment, such as FIG. 4A As shown, sheets 401, 402, 403, 404, and 405 can be placed in a mold 406 to align sheets 401 and 402 containing coils. Coil alignment can be side alignment, pin alignment, or tenon alignment. Unlike existing technologies, batch alignment accuracy is a fixed value, which reduces gap variations among all finished products in batch production.

[0101] In one embodiment, the sheets 401, 402 containing the coils can be aligned using optical alignment such as CCD, laser, or image. FIG. 4B As shown, each of the sheets 401 and 402 has holes 401h and 402h for allowing light from the CCD 500 to pass through, for aligning the sheets 401 and 402 containing the coil. Unlike existing technologies, the batch alignment accuracy is a fixed value, which reduces gap variations across all finished products.

[0102] In one embodiment, the first insulating layer is in contact with the upper surface of the third magnetic sheet 403, and the second insulating layer is in contact with the lower surface of the third magnetic sheet 403.

[0103] In one embodiment, the first coil is formed of a first plurality of conductive layers, wherein a first winding is formed on a first insulating layer disposed on a carrier, wherein a third insulating layer is formed on the first winding, wherein the first insulating layer is in contact with the upper surface of the third magnetic sheet 403.

[0104] In one embodiment, the second coil is formed of a second plurality of conductive layers, wherein a second winding is formed on a second insulating layer disposed on a carrier, wherein a fourth insulating layer is formed on the first winding, and wherein the second insulating layer is in contact with the lower surface of the third magnetic sheet 403.

[0105] In one embodiment, such as FIG. 5The diagram discloses a method for forming multiple coupled inductors, comprising: Step 401: forming a first sheet and a second sheet by a thin-film process, wherein each of the first sheet and the second sheet includes at least one conductive layer. Each conductive layer is formed on a corresponding insulating layer, wherein the at least one conductive layer includes a conductive pattern for forming multiple coils. Step 402: disposing the first sheet on the upper surface of a third magnetic sheet containing magnetic material, and disposing the second sheet on the lower surface of the third magnetic sheet, wherein a fourth sheet is disposed on the upper surface of the first sheet 401, and a fifth sheet is disposed on the upper surface of the third magnetic sheet. Sheet 405 is disposed on the lower surface of the second sheet 402, wherein the stacked sheets are hot-pressed to form a magnetic body, the magnetic body having coupled inductor coils inside. Step 403: cutting the magnetic body into multiple pieces, each piece including a corresponding portion of the magnetic body and two corresponding coils of the coupled inductors within the corresponding portion of the magnetic body. Step 404: spraying paint onto the magnetic body of the coupled inductors. Step 405: Peeling the paint off the magnetic body of the coupled inductor; Step 406: Electroplating Cu paint on the magnetic body; Step 407: Spraying paint; Step 408: Peeling the paint; Step 409: Electroplating Cu / Ni / Sn; Step 410: Finished coupled inductor.

[0106] FIG. 6 The diagram illustrates the alignment of the two distinct coils of a coupled inductor relative to their coupling coefficient and mutual inductance. The misalignment of the first and second coils causes changes in both the coupling coefficient and mutual inductance. Therefore, aligning the two coils of a single-coil coupled inductor allows control over variations in the coupling coefficient and mutual inductance, thereby improving the inductor's reliability.

[0107] In one embodiment, such as FIG. 7A As shown, a coupled inductor is disclosed, comprising: a first coil structure 101 including at least one first conductive layer, wherein each conductive layer is formed on a corresponding insulating layer, the insulating layer starting from a first bottom insulating layer 101b. The first conductive layer is formed on and in contact with the first bottom insulating layer 101b, wherein the at least one first conductive layer includes a first conductive pattern for forming at least one first winding of a first coil; a second coil structure 102 including at least one second conductive layer, wherein each conductive layer is formed on a corresponding insulating layer, starting from a second bottom insulating layer 102b, the second conductive layer is formed on a second bottom and in contact with the second bottom insulating layer 102b, wherein the at least one second conductive layer includes a second conductive pattern for forming at least one second winding of a second coil; the at least one first winding of the first coil structure and the at least one second winding of the second coil structure are stacked vertically and have a vertical distance G between them.

[0108] like FIG. 7A As shown, on a first vertical plane spanning at least one first winding of the first coil structure 101, a first hollow space 101h of the at least one first winding of the first coil structure 101, at least one second winding of the second coil structure 102, and a second hollow space 102h of the at least one second winding of the second coil structure 102, the first midpoint UM1 of the first horizontal line segment L1 and the second midpoint LM1 of the second horizontal line segment L2 are not greater than 1µm. The first horizontal line segment L1 extends from the first innermost edge US1 through the first hollow space 101h to the second innermost edge US2, passing through at least one first hollow space 101h. The second horizontal line segment L2 extends from the third innermost edge LS1 through the second hollow space 102h to the fourth innermost edge LS2. The horizontal distance d is the horizontal distance between the vertical line VU1 passing through the first midpoint UM1 and the vertical line VL1 passing through the second midpoint LM1.

[0109] In one embodiment, such as FIG. 7B As shown, the horizontal distance d is zero, and the vertical line V1 passes through the first midpoint UM1 and the second midpoint LM1.

[0110] In one embodiment, each of the first coil structure 101 and the second coil structure 102 is formed by a corresponding photolithography process, wherein the image pattern of at least one first winding and at least one second winding of the first coil is formed by the same set of image patterns used in the corresponding photolithography process.

[0111] In one embodiment, a first coil structure 101 is disposed on the top surface of a magnetic sheet 103, and a second coil structure 102 is disposed on the bottom surface of a magnetic sheet 103, wherein the first coil structure 101 and the second coil structure 102 are located on opposite sides of the magnetic sheet.

[0112] In one embodiment, such as FIG. 2A As shown, the coupled inductor further includes a first magnet and a second magnet, wherein the first magnet is disposed on the upper surface of the magnetic sheet to cover at least one first winding of the first coil, and wherein the second magnet is disposed on the bottom surface of the magnetic sheet to cover at least one second winding of the second coil.

[0113] In one embodiment, such as FIG. 7A As shown, at least one first conductive layer includes a first plurality of conductive layers, wherein each of the first plurality of conductive layers is sequentially formed on a corresponding insulating layer starting from a first bottom insulating layer, wherein the first bottom insulating layer is in contact with the upper surface of the magnetic sheet.

[0114] In one embodiment, such as FIG. 7CAs shown, at least one first conductive layer includes a first plurality of conductive layers, wherein each of the first plurality of conductive layers is sequentially formed on a corresponding insulating layer starting from a first bottom insulating layer, wherein the first plurality of conductive layers are located between the first bottom insulating layer and a first top of the first coil structure, wherein the first bottom insulating layer is in contact with the upper surface of the magnetic sheet. The horizontal distance d is the horizontal distance between a vertical line VU1 passing through the first midpoint UM1 and a vertical line VL1 passing through the second midpoint LM1.

[0115] In one embodiment, such as FIG. 7C As shown, at least one second conductive layer includes a second plurality of conductive layers, wherein each of the second plurality of conductive layers is sequentially formed on a corresponding insulating layer starting from the second bottom insulating layer, wherein the second bottom insulating layer is in contact with the bottom surface of the magnetic sheet.

[0116] In one embodiment, such as FIG. 7A As shown, at least one second conductive layer includes a second plurality of conductive layers, wherein each of the second plurality of conductive layers is sequentially formed on a corresponding insulating layer starting from the second bottom insulating layer, wherein the second plurality of conductive layers is located between the second bottom insulating layer and the second top insulating layer of the second coil structure, wherein the second top insulating layer is in contact with the bottom surface of the magnetic sheet.

[0117] In one embodiment, such as FIG. 7C As shown, at least one second conductive layer includes a second plurality of conductive layers, wherein each of the second plurality of conductive layers is sequentially formed on a corresponding insulating layer starting from the second bottom insulating layer, wherein the second plurality of conductive layers is located between the second bottom insulating layer and the second top insulating layer of the second coil structure, wherein the second bottom insulating layer is in contact with the bottom surface of the magnetic sheet.

[0118] In one embodiment, such as FIG. 7D As shown, the horizontal distance d is zero, and the vertical line V1 passes through the first midpoint UM1 and the second midpoint LM1.

[0119] In one embodiment, the first magnet includes a first integral magnet that covers at least one first winding of the first coil and extends into a first hollow space of the first coil.

[0120] In one embodiment, the second magnetic body includes a second integral magnetic body that covers at least one second winding of the second coil and extends into the second hollow space of the first coil.

[0121] In one embodiment, a third insulating layer is formed on a first conductive layer, the first conductive layer including a first winding formed on the first insulating layer, wherein the third insulating layer covers the first winding and extends into an unpatterned region of the first winding.

[0122] In one embodiment, a fourth insulating layer is formed on a second conductive layer including a second winding formed on a second insulating layer, wherein the fourth insulating layer covers the second winding and extends into an unpatterned region of the second winding.

[0123] In one embodiment, each of at least one first conductive layer is formed by a coating process.

[0124] In one embodiment, each of at least one first conductive layer is formed by a thin-film process.

[0125] In one embodiment, each of at least one first conductive layer is formed by a thick film process.

[0126] In one embodiment, the first magnetic body is formed of a first material, and the magnetic sheet is formed of a second material different from the first material.

[0127] In one embodiment, each of the first magnetic body and the magnetic sheet is formed of a first material.

[0128] In one embodiment, each of the first magnetic body and the second magnetic body is formed of a first material, and the magnetic sheet is formed of a second material different from the first material.

[0129] In one embodiment, the first magnetic body is formed of a first material, the magnetic sheet is formed of a second material, and the second magnetic body is formed of a third material, wherein the first material, the second material, and the third material are different from each other.

[0130] In one embodiment, a single magnetic body is disposed above the first coil and extends into the first hollow space of the first coil and the second hollow space of the second coil.

[0131] In one embodiment, the first electrode, the second electrode, the third electrode, and the fourth electrode are disposed on the bottom surface of a magnet including the first magnet and the second magnet.

[0132] In one embodiment, on a second vertical plane spanning at least one first winding of the first coil structure, the first hollow space of the at least one first winding of the first coil structure, the second winding of the at least one second coil structure, and the second hollow space of the at least one second winding of the second coil structure, the second horizontal distance between the third midpoint and the fourth midpoint of the third horizontal line segment, and the length of the fourth horizontal line segment is not greater than 1 μm, wherein the third horizontal line segment extends from the fifth innermost edge through the first hollow space to the sixth innermost edge; the fourth horizontal line segment extends from the seventh innermost edge through the second hollow space to the eighth innermost edge, wherein the second vertical plane is perpendicular to the first vertical plane.

[0133] This invention offers the following advantages: Single-coil structures can be produced using photolithography; through assembly, the first and second coils with identical structures can be precisely aligned online on the same axis, resulting in better and more reliable coupling coefficients for coupled inductors in mass production. Through structural design optimization, particularly utilizing the flatness of the bottom insulating layer and the bottom surface of the upper coil structure, the standard deviation of the gap between the upper and lower coils in the finished coupled inductor can be reduced from 2.6 to 0.6. The insulating layer of the lower coil structure forms the gap between the upper and lower coils of the coupled inductor, improving product reliability and performance. Furthermore, this invention improves the product quality and yield rate of coupled inductors by utilizing the flatness of the bottom insulating layer of the upper and lower coil structures.

[0134] This invention offers the following advantages: Through structural design optimization, particularly by utilizing the flatness of the bottom insulation, the standard deviation of the gap between the upper and lower coils in the finished coupled inductor can be reduced from 2.6 to 0.6. The flatness of the layers of the upper coil structure and the bottom insulation layer of the lower coil structure, which forms the gap between the upper and lower coils of the coupled inductor, improves product reliability and performance. Furthermore, this invention improves the product quality and yield rate of coupled inductors, thereby effectively achieving the objectives of this invention by utilizing the flatness of the bottom insulation layers of both the upper and lower coil structures.

Claims

1. A method for forming a coupled inductor, characterized in that, Include: A first coil structure is formed on a first carrier, wherein the first coil structure includes at least one first conductive layer formed on a first insulating layer, the at least one first conductive layer including a first conductive pattern for forming at least one first winding of a first coil; A second coil structure is formed on a second carrier, wherein the second coil structure includes at least one second conductive layer formed on a second insulating layer, the at least one second conductive layer including a second conductive pattern for forming at least one second winding of a second coil; and The second coil structure, the magnetic sheet, and the first coil structure are sequentially placed in a mold, aligned, and then joined together to form a magnetic body. The first conductive layer and the second conductive layer are formed by either a coating process or a photolithography process.

2. The forming method according to claim 1, characterized in that: It also includes removing the first carrier and the second carrier to obtain a first sheet and a second sheet, the first sheet including the first insulating layer and the first coil structure, the second sheet including the second insulating layer and the second coil structure, and the magnetic body being obtained by sequentially placing the second sheet, the magnetic sheet and the first sheet in the mold and aligning them together.

3. The forming method according to claim 1, characterized in that: The first coil structure, the magnetic sheet, and the second coil structure are aligned using any one of the optical methods of CCD, laser, and image.

4. The forming method according to claim 1, characterized in that: After the first coil structure, the magnetic sheet, and the second coil are aligned, on the first vertical plane spanning the first hollow space of the first coil structure and the second hollow space of the second coil structure, a first horizontal distance between the midpoint of the first horizontal line segment and the midpoint of the second horizontal line segment is no greater than 1 μm. The first horizontal line segment extends from the first innermost edge of the first winding of the first coil through the first hollow space to the corresponding second innermost edge of the first winding of the first coil, and the second horizontal line segment extends from the third innermost edge of the second winding of the second coil through the second hollow space to the corresponding fourth innermost edge of the second winding of the second coil.

5. The forming method according to claim 1, characterized in that: The first coil structure, the magnetic sheet, and the second coil structure are aligned and then joined together by thermoforming to form the magnetic body.

6. The forming method according to claim 1, characterized in that: It also includes cutting a magnetic body into multiple pieces, each piece containing a corresponding part of the magnetic body and two corresponding coils of a coupled inductor within the corresponding part of the magnetic body, and electroplating Cu / Ni / Sn onto the cut magnetic body to obtain the finished coupled inductor.

7. The forming method according to claim 1, characterized in that: The first coil structure and the second coil structure are formed by corresponding photolithography processes.

8. The forming method according to claim 7, characterized in that: The image patterns of at least one first winding of the first coil and at least one second winding of the second coil are formed using the same set of image patterns in a photolithography process.

9. The forming method according to claim 2, characterized in that: The magnetic body is formed by sequentially placing the fifth magnetic sheet, the second sheet, the magnetic sheet, the first sheet, and the fourth magnetic sheet into the mold, aligning them, and then combining them.

10. The forming method according to claim 9, characterized in that, The magnetic body has a first magnetic body made of a fourth magnetic sheet and a second magnetic body made of a fifth magnetic sheet. The first magnetic body covers at least one first winding of the first coil and extends into a first hollow portion of the first coil. The second magnetic body covers at least one second winding of the second coil and extends into a second hollow portion of the second coil.

11. The forming method according to claim 9, characterized in that, The first sheet and the second sheet each have a plurality of holes for passing through to align the first sheet and the second sheet.

12. The forming method according to claim 10, characterized in that, The first magnetic body is formed of a first material, and the magnetic sheet is formed of a second material different from the first material.

13. The forming method according to claim 10, characterized in that, The first magnetic body is formed of a first material, the magnetic sheet is formed of a second material, and the second magnetic body is formed of a third material, wherein the first material, the second material, and the third material are different from each other.

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