TWI658483B - Charging coil and the manufacturing method for making the same - Google Patents

Abstract

A charging coil and a manufacturing method thereof. The charging coil includes: a substrate having at least one set of conductive holes; at least one coil structure formed on the substrate, and two ends of each coil structure are connected to a set of conductive holes; a support; The layer is formed in the gap and the periphery of the coil structure to support the coil structure.

Description

Charging coil and manufacturing method thereof

The invention relates to a substrate, in particular to a charging coil and a method for manufacturing the same.

At present, wireless charging technology is gradually deepening into various fields, such as mobile devices, computers and other electronic products, other electronic products, electric vehicles, and even mobile wearable devices such as electronic shoes and electronic clothing. In the future, if the charging efficiency problem of wireless charging technology can be solved, wireless charging technology may become the mainstream of future charging.

Currently there are four main types of wireless charging technologies: magnetic induction (Reductant Coupling), magnetic resonance (Resonant Coupling), microwave transmission (Microwave Power Transfer) and laser transmission (Laser Power Transfer). At this stage, magnetic induction and magnetic resonance are relatively mature wireless charging technologies. Both of these wireless charging technologies must be equipped with a charging coil on the charging base and the device. Among them, the short-range wireless charging is currently the mainstream of magnetic induction, as long as the problem of alignment can be confirmed, such as mobile devices, small electronic products, mobile wearable devices, etc .; long-range wireless charging, using magnetic induction It is mainly used for wireless charging technology of electric vehicles.

When the wireless charging coil is applied to different products, it may be integrated in different positions. For example, in the application of mobile phones or tablet computers, the charging coil may be integrated into the back cover or the battery. Road boards. For example, when the charging base is applied to products such as tables and shoe racks, it must be integrated into a wooden desktop or plastic board.

At this stage, the manufacturing method of the charging coil mainly adopts a wound structure, that is, through a pre-made enameled wire (the diameter of which is made according to the specifications of the charging coil), the wire is wound to a predetermined number of turns and area, and then bonded On the substrate. The limitation is that the thickness is large, and the quality depends on the quality of the enameled wire and is relatively unstable.

Therefore, how to develop a high-density charging coil with a single plane, the largest number of turns, and the thinnest thickness at the same time, and with a simple process and a high yield rate, has become the future development direction of the charging coil.

In order to achieve the above object, the present invention provides a charging coil and a manufacturing method thereof, which are manufactured by using lithography technology to achieve a single plane, the highest number of turns, and the thinnest high-density charging coil. Moreover, the manufacturing process is simple and the yield is high. Technical efficacy.

The present invention provides a charging coil, comprising: a substrate having at least one set of lead-through holes; at least one coil structure formed on the substrate, and two ends of each of the coil structures are connected to a set of lead-through holes, the The coil structure is made of a metal material, the aspect ratio is between 2: 1 and 1:10, the line width is between 1 micrometer and 300 micrometers, and the thickness is between 10 micrometers and 150 micrometers; and, a support A layer is formed on the gap and the periphery of the coil structure to support the coil structure.

The invention further provides a method for manufacturing a charging coil, comprising: providing a substrate with a sub-metal layer, the substrate having at least two sets of conductive holes, each set of two conductive holes; forming a photoresist layer on the substrate Top; fabricating at least one coil structure recess on the photoresist layer by a lithography process Grooves, two ends of each of the coil structure grooves are arranged at the corresponding group of conductive holes; the seed metal layer is plated so that each of the coil structure grooves and the group of conductive holes are filled with electroplated metal to form a Coil structure; removing the photoresist layer; etching the seed metal layer that is not within the scope of the coil structure to isolate the wires of the coil structure from each other; and covering the coil structure with a negative photoresist and filling the coil structure The gap of the coil structure forms a supporting layer structure.

The invention further provides a method for manufacturing a charging coil, comprising: providing a substrate having at least one set of conductive holes, each set of two conductive holes; sequentially forming a negative photoresist layer and a lift-off photoresist layer On the substrate; a lithographic process is used to form a coil structure groove on the negative photoresist layer and the lift-off photoresist layer, and two ends of the coil structure groove are arranged at the corresponding group of guide holes Forming a metal film on the substrate having the lift-off photoresist layer; removing the lift-off photoresist layer so that the coil structure groove has the metal film; electroplating the metallic film so that the coil structure groove And forming a coil structure with the set of lead-through holes filled with electroplated metal; and forming a protective layer to cover the coil structure.

The invention further provides a method for manufacturing a charging coil, comprising: providing a substrate having at least one set of conductive holes, each set of two conductive holes; sequentially forming a photoresist layer and a lift-off photoresist layer on the substrate; On the substrate; at least one coil structure groove is made on the photoresist layer and the lift-off photoresist layer by a lithography process, and two ends of each of the coil structure grooves are arranged in the corresponding group of guide holes; Forming a metal thin film on the substrate having the lift-off photoresist layer; removing the lift-off photoresist layer so that the coil structure groove has the metal film; electroplating the metal film so that the coil structure groove and the The group of conductive holes is filled with electroplated metal to form a coil structure; the photoresist layer is removed; and a negative photoresist layer is used to cover the coil structure and fill the gaps of the coil structure to form a support layer structure.

In order to make the above and other objects, features, and advantages of the present invention more comprehensible, several preferred embodiments are exemplified below, which are described in detail below in conjunction with the accompanying drawings (embodiments).

2, 3‧‧‧ partial

10‧‧‧ substrate

20, 21‧‧‧seed metal layer

22‧‧‧Metal Film

30A, 30B‧‧‧Guide hole

40‧‧‧Photoresist layer

41‧‧‧partial photoresist layer

50‧‧‧ Coil structure groove

60‧‧‧coil structure

70‧‧‧ negative photoresist layer

71‧‧‧protective layer

80‧‧‧ negative photoresist layer

81a‧‧‧Photoresistive layer

90‧‧‧ lift off photoresist layer

FIG. 1A is a schematic top view of a charging coil of the present invention.

FIG. 1B is an enlarged schematic view of part 2 of the charging coil of the present invention.

Figures 2A-2B are schematic top views of the main steps of forming a coil structure groove and a coil structure on a substrate with a conductive hole according to the present invention.

FIG. 3A is a flowchart of an embodiment of the present invention using the seed metal layer to make the charging coil of the present invention.

Figs. 3B-3H, a part 2 of Fig. 2A of the present invention, are enlarged production flow diagrams along the A-A section.

FIG. 4A is a flowchart of an embodiment of the present invention using a substrate without a seed metal layer to fabricate a charging coil of the present invention.

Figures 4B-4H, part 2 of Figure 2A of the present invention, are enlarged schematic production flow diagrams along the A-A section.

FIG. 5A is a flowchart of an embodiment of the present invention using a substrate without a seed metal layer to make the charging coil of the present invention.

Fig. 5B-5I, part 2 of Fig. 2A of the present invention, is a schematic enlarged production flow chart along the A-A section.

FIG. 6 shows an embodiment in which the coil structure 60 of the present invention has three coils close to each other in parallel.

FIG. 7 shows an embodiment in which a plurality of sets of coil structures of the present invention are simultaneously formed on a single substrate.

According to the embodiment of the present invention, the present invention uses a lithography process to make a coil structure groove with a high aspect ratio, and uses a plating technology to make the coil structure, thereby completing the charging coil. The charging coil and method of the present invention have special technical functions such as simple construction method, high yield, can be directly manufactured on the target substrate, and low cost, and can fully meet the purpose of a large number of future wireless products for electronic charging coils.

Please refer to FIG. 1A for a schematic diagram of a top view of a charging coil of the present invention, including: a substrate 10 and a coil structure 60; and FIG. 1B, an enlarged schematic view of a part 2 of the charging coil of the present invention. A set of guide holes 30A, 30B. The lead-through holes 30A and 30B are perforated to the back of the substrate 10 to connect with the lead-through pads formed later. The lead pad is soldered or connected to an external flexible board, etc., and is connected to an external control circuit board.

The coil structure 60 is made of a metal material, and has an aspect ratio between 10: 1 and 1:10, a line width between 1 micrometer and 300 micrometers, and a thickness between 10 micrometers and 150 micrometers. In addition, a support layer is arranged between the coil structures 60 and is formed in the gaps and the periphery of the coil structures 60 to support the coil structures 60.

Next, please refer to FIGS. 2A-2B, which are schematic top views illustrating the main steps of forming a coil structure groove and a coil structure on a substrate with a guide hole in the present invention. FIG. 2A illustrates that the substrate 10 having the lead-through holes, that is, the lead-through holes 30A, 30B, can be pre-formed with a sub-type. The metal layer 20 (please refer to FIG. 3B), or does not have a seed metal layer (please refer to FIGS. 4B and 5B). FIG. 2B illustrates the use of a lithography process to fabricate a coil structure groove 50. The coil structure groove 50 is composed of a photoresist layer 40 (refer to FIGS. 3C and 3D). FIG. 1A illustrates that a coil structure 60 is formed in the coil structure groove 50.

In the following, several embodiments will be listed to explain the specific method of the present invention. Figures 3A-3H illustrate an embodiment of the present invention using a seed metal layer to make the charging coil of the present invention; Figures 4A-4H illustrate the present invention An embodiment of the charging coil of the present invention without using a seed metal layer; FIGS. 5A-5H illustrate another embodiment of the charging coil of the present invention without using a seed metal layer.

Please refer to FIG. 3A, which is a flowchart of an embodiment of the present invention using a seed metal layer to make the charging coil of the present invention. In the following, it is matched with FIGS. 3B-3G, which is part 2 of FIG. 2A. A schematic flowchart to explain the steps of Figure 3A:

Step 101: Provide a substrate with a sub-metal layer. The substrate has at least two sets of lead-through holes, each set of two lead-through holes. This step is the state of FIG. 2A. In addition, in FIG. 3B, the state of Part 2 in FIG. 2A is shown, and the seed metal layer 20 is disposed inside the lead-through hole 30B and the surface of the substrate 10.

Step 102: forming a photoresist layer on the substrate. This step is shown in FIG. 3C. The photoresist layer 40 is spread on the substrate 10, that is, the seed metal layer 20, and the conductive hole 30B is also filled.

Step 103: A photolithography process is used to form a coil structure groove on the photoresist layer, and two ends of the coil structure groove are arranged at the corresponding group of guide holes. This step is the 3D picture As shown, after the photoresist layer 40 is removed by the developer through the lithography process, only a portion of the photoresist layer 41 remains, and the hollowed-out portion constitutes the coil structure groove 50.

Step 104: The seed metal layer is electroplated, so that each of the coil structure grooves and the group of conductive holes is filled with electroplated metal to form a coil structure. This step is shown in FIG. 3E. Since the seed metal layer 20 is above the substrate 10, after the coil structure groove 50 is made in step 103, the seed metal layer 20 underneath will be exposed. By performing the electroplating process, the exposed seed metal layer 20 can be filled with electroplated metal to form a coil structure 60. However, at this time, since the seed metal layer 20 covers the top of the substrate 10, the coil structure 60 is currently short-circuited. Therefore, more seed metal layers 20 must be removed next.

Step 105: Remove the photoresist layer. This step is shown in FIG. 3F. After removing the remaining photoresist layer 41, only the coil structure 60 and the seed metal layer 20 below it will be left, and the seed metal layer 20 not covered by the coil structure 60 will be exposed.

Step 106: The seed metal layer outside the coil structure is etched to isolate the wires of the coil structure from each other. The exposed seed metal layer 20 is etched by using an etchant to isolate the lines of the coil structure 60 from each other, as shown in FIG. 3G. It can be found that the part 3 includes the coil structure 60 and the seed metal layer 21 that is not etched below it.

Step 107: Cover the coil structure with a negative photoresistor and fill the gaps of the coil structure to form a support layer structure. Finally, the entire coil structure 60 is covered with a negative photoresist layer 70, including the gap. In this way, the negative photoresist layer 70 can form a supporting layer structure to support and insulate the coil structure 60, as shown in FIG. 3H.

In addition, a magnetically permeable material layer can be formed on the support layer 70 to allow the coil structure 60 The charging effect is better.

In addition, a protective layer may be formed on the support layer 70.

Next, please refer to FIG. 4A. The present invention uses a substrate without a seed metal layer to make a flowchart of an embodiment of the charging coil of the present invention. In the following, it is matched with FIGS. 4B-4H, which is part 2 of FIG. 2A. A schematic diagram of the enlarged production process of the AA section to explain the steps of Figure 4A:

Step 111: Provide a substrate with at least one set of conductive holes, each set of two conductive holes. This step is a state of another embodiment of FIG. 2A, that is, an enlarged cross-sectional view of part 2, and it can be seen that the conductive hole 3013 penetrates the substrate 10, as shown in FIG. 4B.

Step 112: A negative photoresist layer and a lift-off photoresist layer are sequentially formed on the substrate; the negative photoresist layer 80 and the lift-off photoresist layer 90 are used as a permanent layer and a temporary layer, respectively. 4C figure.

Step 113: a lithography process is used to form a coil structure groove on the negative photoresist layer and the lift-off photoresist layer, and two ends of the coil structure groove are arranged at the corresponding group of guide holes; The lithography process performs a one-time exposure, and at the same time, the negative photoresist layer 80 and the photoresist layer 90 are developed with a developer to develop a coil structure groove 50, leaving a portion of the negative photoresist layer 81. 3. Lift off the photoresist layer 91, as shown in FIG. 4D.

Step 114: forming a metal thin film on the substrate having the lift-off photoresist layer; forming the metal thin film 21 on the substrate 10 by sputtering or spraying. Since the substrate 10 is already the substrate 10 with the coil structure groove 50, the coil structure groove 50, the remaining lift-off photoresist layer 91, and the conductive hole 30B will be covered with a metal thin film 22, as shown in Section 4E. As shown.

Step 115: remove the lift-off photoresist layer, so that the coil structure groove has the In this step, after the lift-off photoresist layer 91 is removed, the metal film 22 above it is also removed, so only the metal film 22 in the coil structure groove 50 remains, and The portion to be retained in the present invention is shown in FIG. 4F.

Step 116: electroplating the metal thin film, so that the coil structure and the two perforations are filled with electroplated metal; the metal thin film 21 is used as a substrate, and an electroplating process can be performed to form a coil structure 60, as shown in FIG. 4G.

Step 117: forming a protective layer to cover the coil structure. The remaining negative photoresist layer 81 will form a supporting structure, and a protective layer 71 will be formed to insulate the coil structure 60, as shown in FIG. 4H.

Similarly, a magnetically permeable material layer can be formed on the protective layer 71, so that the charging effect of the coil structure 60 is better.

Please refer to FIG. 5A. The present invention uses a substrate without a seed metal layer to make a flow chart of an embodiment of the charging coil of the present invention. Below, it is matched with FIGS. 5B-5I, which is part 2 of FIG. 2A, along the AA section. The enlarged schematic diagram of the production process to explain the steps of Figure 5A:

Step 121: Provide a substrate with at least one set of lead-through holes, each set of two lead-through holes; this step is a state of another embodiment of FIG. 2A, that is, an enlarged cross-sectional schematic view of part 2, It is seen that the via hole 30B penetrates the substrate 10 as shown in FIG. 5B.

Step 122: sequentially forming a photoresist layer and a lift-off photoresist layer on the substrate; the photoresist layer 80a and the lift-off photoresist layer 90 are respectively used as temporary layers, as shown in FIG. 5C.

Step 123: At least one coil structure is fabricated on the photoresist layer and the lift-off photoresist layer by a lithography process, and two ends of each of the coil structures are arranged at the corresponding group of guide holes; The photolithography process performs a one-time exposure, and the developer is used to develop the photoresist layer 80a and lift off the photoresist layer 90 to develop a coil structure groove 50, leaving a portion of the photoresist layer 81a and lift off the light. The resist layer 91 is shown in FIG. 5D.

Step 124: forming a metal thin film on the substrate having the lift-off photoresist layer; since the substrate 10 is already the substrate 10 having the coil structure groove 50, the coil structure groove 50 and the remaining lift-off photoresist layer Above the 91 and the guide hole 30B, etc., a metal thin film 22 will be distributed, as shown in FIG. 5E.

Step 125: remove the lift-off photoresist layer so that the metal film is included in the coil structure; in this step, after the lift-off photoresist layer 91 is removed, the metal film 22 above it is removed together Therefore, only the metal thin film 22 in the groove 50 of the coil structure is left, and the part to be retained in the present invention is shown in FIG. 5F.

Step 126: Electroplating the metal thin film, so that the coil structure and the two perforations are filled with electroplated metal; the metal thin film 21 is used as a substrate, and an electroplating process may be performed to form a coil structure 60, as shown in FIG. 5G.

Step 127: Remove the photoresist layer; remove the remaining photoresist layer 81a, and the coil structure 60 is exposed, as shown in FIG. 5H.

Step 128: Cover the coil structure with a negative photoresist layer and fill the gaps of the coil structure to form a supporting layer structure. Finally, the entire coil structure 60 is covered with a negative photoresist layer 70, including the gap. In this way, the negative photoresist layer 70 can form a supporting layer structure to support and insulate the coil structure 60, as shown in FIG. 5I.

In addition, a magnetically permeable material layer can be formed on the support layer.

Through the manufacturing process of the present invention, a high-density charging coil with a single plane, the largest number of turns, and the thinnest thickness can be manufactured, and the manufacturing process is simple and the yield is high.

At the same time, the present invention can also arbitrarily make multiple sets of multi-turn coils connected in parallel to the same lead-through hole. Please refer to FIG. 6, which is an embodiment in which the coil structure 60 has three coils in close proximity at the same time in parallel. In other words, the coil structure of the present invention may be more than two groups and connected in parallel to each other and connected to the same group of connection holes in common.

In addition, the present invention can also make multiple sets of coil structures on the same substrate at the same time and let them be connected in parallel to solve the problem of alignment. Please refer to FIG. 7, which is an embodiment of the coil structure 60A, 60B, 60C, 60D, 60E, 60F, 60G, 60H, 60I of the coil structure of the present invention formed on a single substrate 10 at the same time. Parallel to each other. In this way, the problem of misalignment and ineffective charging can be avoided.

In addition, the material of the substrate is selected from glass, sapphire, or ceramic materials.

Although the technical content of the present invention has been disclosed as above with preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art and making some changes and retouching without departing from the spirit of the present invention should be covered by the present invention. Therefore, the scope of protection of the present invention shall be determined by the scope of the appended patent application.

Claims (21)

A method for manufacturing a charging coil includes: providing a substrate having a sub-metal layer, the substrate having at least two sets of lead-through holes, each set having two lead-through holes; forming a photoresist layer on the substrate; The photoresist process creates at least one coil structure groove in the photoresist layer, and two ends of each of the coil structure grooves are arranged at the corresponding group of conductive holes; the seed metal layer is plated to make each coil structure The groove and the set of contact holes are filled with electroplated metal to form a coil structure; the photoresist layer is removed; the seed metal layer outside the coil structure area is etched to isolate the coil structure lines and lines from each other; and a A negative photoresist covers the coil structure and fills the gaps of the coil structure to form a support layer structure. The method for manufacturing a charging coil according to claim 1, further comprising: forming a magnetically permeable material layer on the support layer. The method for manufacturing a charging coil according to claim 1, wherein each of the coil structures is connected in parallel by at least two sets of coils and is commonly connected to the set of guide holes. The method for manufacturing a charging coil according to claim 1, wherein the at least one coil structure is two or more groups and connected in parallel with each other. The method for manufacturing a charging coil according to claim 1, wherein the coil structure has an aspect ratio between 10: 1 and 1:10, a line width between 1 micrometer and 300 micrometers, and a thickness between 10 micrometers To 150 microns. The method for manufacturing a charging coil according to claim 1, wherein the material of the substrate is selected from the group consisting of glass, sapphire, and ceramic materials. A method for manufacturing a charging coil includes: providing a substrate having at least one set of conductive holes, each set of two conductive holes; sequentially forming a negative photoresist layer and a lift-off photoresist layer on the substrate ; At least one coil structure groove is made by the lithography process on the negative photoresist layer and the lift-off photoresist layer, and two ends of the coil structure groove are arranged at the corresponding group of guide holes; The metal film is on the substrate having the lift-off photoresist layer; the lift-off photoresist layer is removed to make the metal film in the coil structure groove; the metal film is electroplated to make the coil structure groove and the group The lead-through hole is filled with electroplated metal to form a coil structure; and a protective layer is formed to cover the coil structure. The method for manufacturing a charging coil according to claim 7, further comprising: forming a magnetically permeable material layer on the protective layer. The method for manufacturing a charging coil according to claim 7, wherein the coil structure is composed of at least two sets of coils connected in parallel and commonly connected to the set of guide holes. The method for manufacturing a charging coil according to claim 7, wherein the coil structure has an aspect ratio between 10: 1 and 1:10, a line width between 1 micrometer and 300 micrometers, and a thickness between 10 micrometers To 150 microns. The method for manufacturing a charging coil according to claim 7, wherein the at least one coil structure is composed of two or more groups and connected in parallel with each other. The method for manufacturing a charging coil according to claim 7, wherein the material of the substrate is selected from the group consisting of glass, sapphire, and ceramic materials. A method for manufacturing a charging coil includes: providing a substrate having at least one set of conductive holes, each set of two conductive holes; sequentially forming a photoresist layer and a lift-off photoresist layer on the substrate; and The lithography process produces at least one coil structure groove on the photoresist layer and the lift-off photoresist layer, and two ends of each of the coil structure grooves are arranged in the corresponding group of lead-through holes; forming a metal film On the substrate having the lift-off photoresist layer; removing the lift-off photoresist layer so that the metal film is in the coil structure groove; electroplating the metal film so that the coil structure groove and the two sets of guides The contact hole is filled with electroplated metal to form a coil structure; the photoresist layer is removed; and a negative photoresist layer is used to cover the coil structure and fill the gaps of the coil structure to form a support layer structure. The method for manufacturing a charging coil according to claim 13, further comprising: forming a magnetically permeable material layer on the support layer. The method for manufacturing a charging coil according to claim 13, wherein the coil structure is composed of at least two sets of coils connected in parallel and commonly connected to the set of guide holes. The method for manufacturing a charging coil according to claim 13, wherein the coil structure has an aspect ratio between 10: 1 and 1:10, a line width between 1 micrometer and 300 micrometers, and a thickness between 10 micrometers To 150 microns. The method for manufacturing a charging coil according to claim 13, wherein the at least one coil structure is composed of two or more groups and is connected in parallel with each other. The method for manufacturing a charging coil according to claim 13, wherein the material of the substrate is selected from the group consisting of glass, sapphire, and ceramic materials. A charging coil manufactured by the manufacturing method of claim 1, comprising: a substrate having a sub-metal layer, the substrate having at least two sets of conductive holes, each set of two conductive holes; at least one coil structure groove , Two ends of each of the coil structure grooves are arranged in the corresponding group of conductive holes; a coil structure, each of the coil structure grooves and the group of conductive holes; and a support layer, which is connected with a negative A photoresist is formed by covering the coil structure and filling a gap of the coil structure. A charging coil manufactured by the manufacturing method of claim 7, comprising: a substrate having at least one set of lead-through holes, each set of lead-through holes having at least two; and at least one coil structure groove, two of the coil structure grooves The end points are arranged in the corresponding set of lead-through holes; a coil structure is formed by filling the coil structure groove and the set of lead-through holes with electroplated metal; and a protective layer covering the coil structure. A charging coil manufactured by the manufacturing method of claim 13, comprising: a substrate having at least one set of lead-through holes, each set of lead-through holes having at least two; and at least one coil structure groove, each of the coil structure grooves The two ends are arranged in the corresponding set of lead-through holes; a coil structure is formed by filling the coil structure groove and the two sets of lead-through holes with electroplated metal; a support layer with a negative photoresist The layer is formed by covering the coil structure and filling a gap of the coil structure.