Transformer and electronic device

Abstract

The application discloses a transformer and electronic equipment. The transformer comprises a substrate, a magnetic core, a first coil and a second coil. The substrate comprises a first surface and a second surface arranged oppositely. At least part of the magnetic core is located in the substrate. The substrate is provided with a first coil groove and a second coil groove. The first coil groove and the second coil groove are communicated with the first surface at least. The first coil is located in the first coil groove and wound on the magnetic core. The second coil is located in the second coil groove and wound on the magnetic core. Through the above scheme, the transformer is applicable to a high-power circuit without increasing the size.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of semiconductor technology, in particular to a transformer and an electronic device. BACKGROUND

[0002] Balun is a kind of transformer, also known as balanced-unbalanced transformer, which mainly functions to complete the conversion between single-ended transmission and differential transmission. The magnetic coupling transformer balun is the most common type of balun, which is basically composed of a magnetic core and two different conductors wound on the magnetic core. By grounding one side of the primary winding, an unbalanced condition is generated on the primary side, and a balanced condition is generated on the secondary side.

[0003] The existing balun has a large resistance of the conductors, which is difficult to meet the demand of high-power circuits. SUMMARY

[0004] The technical problem solved by the present application is to provide a transformer and an electronic device that can be applied to high-power circuits without increasing the size.

[0005] To solve the above technical problem, one technical solution adopted by the present application is to provide a transformer, comprising a substrate, a magnetic core, a first coil and a second coil, wherein the substrate comprises a first surface and a second surface arranged oppositely; at least part of the magnetic core is located in the substrate, wherein the substrate is provided with a first coil slot and a second coil slot, and the first coil slot and the second coil slot are in communication with at least the first surface; the first coil is located in the first coil slot and surrounds the magnetic core; and the second coil is located in the second coil slot and surrounds the magnetic core.

[0006] To solve the above technical problem, another technical solution adopted by the present application is to provide an electronic device comprising the transformer in any of the embodiments.

[0007] The beneficial effects of the present application are as follows: Different from the prior art, at least part of the magnetic core, the first coil slot and the second coil slot of the transformer and the electronic device provided by the present application are located in the substrate. Since the first coil is located in the first coil slot and the second coil is located in the second coil slot, the first coil and the second coil are also located in the substrate. On the one hand, the structure of the present application can fully utilize the overall thickness of the transformer device, and the thickness of the first coil and the second coil is increased without increasing the size of the transformer device, thereby increasing the cross section of the coil and reducing the resistance of the coil. Since the resistance of the coil is reduced, the current through the coil is increased, so that the transformer can be adapted to high-power circuits. On the other hand, the integration of the magnetic core, the first coil, the second coil and the substrate is high, and the process flow is simple and efficient. BRIEF DESCRIPTION OF DRAWINGS

[0008] Figure 1 is a structural schematic diagram of one embodiment of the transformer of the present application;

[0009] Figure 2 is Figure 1 is a sectional view along A-A direction in

[0010] Figure 3 is a structural schematic diagram of another embodiment of the transformer of the present application;

[0011] Figure 4 is a structural schematic diagram of another embodiment of the transformer of the present application;

[0012] Figure 5 is Figure 4 is a sectional view along B-B direction in

[0013] Figure 6 is a structural schematic diagram of another embodiment of the transformer of the present application;

[0014] Figures 7a-7h is a structural schematic diagram of each step of the manufacturing method of the transformer of the present application. DETAILED DESCRIPTION

[0015] In order to make the purpose, technical scheme and effects of the present application more clear and explicit, the present application is further described in detail below with reference to the accompanying drawings and embodiments. Obviously, the described embodiments are only some of the embodiments of the present application, but not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0016] Reference is made to Figure 1 , Figure 1 is a structural schematic diagram of one embodiment of the transformer of the present application. The transformer 10 comprises a substrate 11, a magnetic core 12, a first coil 13 and a second coil 14. The substrate 11 comprises a first surface 11a and a second surface 11b arranged oppositely. Specifically, the material of the substrate 11 can be silicon, glass or PCB (printed circuit board) and the like, and the shape can be square or circular and the like, which is not specifically limited in the present application. Further, the substrate 11 can be a wafer, so as to realize a wafer-level transformer packaging structure, wherein in the present embodiment, the first surface 11a is a functional surface of the wafer, and the second surface 11b is a non-functional surface of the wafer. In other embodiments, the first surface 11a can be a non-functional surface of the wafer, and the second surface 11b is a functional surface of the wafer.

[0017] At least part of the magnetic core 12 is located in the substrate 11, wherein the substrate 11 is provided with a first coil groove 111 and a second coil groove 112, which are at least in communication with the first surface 11a. The first coil 13 is located in the first coil groove 111 and surrounds the magnetic core 12, and the second coil 14 is located in the second coil groove 112 and surrounds the magnetic core 12.

[0018] Specifically, the magnetic core 12 is made of a material with ferromagnetism, such as iron, nickel, chromium, alloys or oxides thereof, etc. In the embodiment, the first coil groove 111 and the second coil groove 112 are blind holes open on the first surface 11a, i.e., neither of the first coil groove 111 and the second coil groove 112 is in communication with the second surface 11b. The first coil groove 111 and the second coil groove 112 can be formed on the substrate 11 by etching or the like. As shown in Figure 1 , the depth direction of the first coil groove 111 and the second coil groove 112 is the thickness direction of the substrate 11 (i.e., the Z direction in Figure 1 ). Figure 2 is Figure 1 the cross-sectional view of A-A direction in Figure 2 , the first coil groove 111 and the second coil groove 112 surround in the extension plane of the substrate 11, and the extension direction of the first coil groove 111 and the second coil groove 112 is as shown in

[0019] Optionally, continuing to refer to Figure 1 and Figure 2 , the magnetic core 12 includes a first magnetic core part 121 located on the first surface 11a side of the substrate 11, a second magnetic core part 122 located on the second surface 11b side of the substrate 11, a third magnetic core part 123 penetrating the substrate 11, and a fourth magnetic core part 124 penetrating the substrate 11 and spaced apart from the third magnetic core part 123, the first magnetic core part 121 connects one end of the third magnetic core part 123 and the fourth magnetic core part 124, and the second magnetic core part 122 connects the other end of the third magnetic core part 123 and the fourth magnetic core part 124. As shown in Figure 1As shown, the magnetic core 12 has a closed loop structure, and since the third magnetic core part 123 and the fourth magnetic core part 124 both penetrate the substrate 11, the space in the substrate 11 is fully utilized to form the magnetic core 12, and meanwhile, the first coil 13 and the second coil 14 can also be arranged to surround the magnetic core 12 inside the substrate 11, thereby realizing the miniaturization of the transformer 10. In addition, the high integration of the magnetic core 12 and the substrate 11 makes the preparation process simple and efficient.

[0020] Optionally, in the present embodiment, the first coil 13 surrounds the third magnetic core part 123, and the second coil 14 surrounds the fourth magnetic core part 124. That is, the third magnetic core part 123 is the primary side of the magnetic core 12, and the fourth magnetic core part 124 is the secondary side of the magnetic core 12.

[0021] Optionally, continuing to refer to Figure 1 The transformer 10 of the present application further comprises a first dielectric layer 15 and a second dielectric layer 16. The first dielectric layer 15 is arranged between the substrate 11 and the first magnetic core part 121, and the third magnetic core part 123 and the fourth magnetic core part 124 both penetrate the first dielectric layer 15. The second dielectric layer 16 is arranged between the substrate 11 and the second magnetic core part 122, and the third magnetic core part 123 and the fourth magnetic core part 124 both penetrate the second dielectric layer 16. The first dielectric layer 15 is used to form an insulating layer between the first magnetic core part 121 and the first coil 13 and the second coil 14, and the second dielectric layer 16 is used to form an insulating layer between the second magnetic core part 122 and the first coil 13 and the second coil 14, thereby avoiding short circuit between the magnetic core 12 and the two coils.

[0022] Optionally, the transformer 10 further comprises two first connection terminals 132 and two second connection terminals 142. The two first connection terminals 132 are located on the first surface 11a side of the substrate 11, and the two first connection terminals 132 are respectively electrically connected to the two ends of the first coil 13. Specifically, in order to facilitate the electrical connection between the first coil 13 and the external device through the first connection terminal 132 without being disturbed by the magnetic core 12, the two first connection terminals 132 are both arranged on the outside of the magnetic core 12. In the present embodiment, the two first connection terminals 132 are both arranged on the side of the third magnetic core part 123 away from the fourth magnetic core part 124, and are respectively used as the output terminal and the input terminal of the first coil 13. Similarly, the two second connection terminals 142 are located on the first surface 11a side of the substrate 11, and the two second connection terminals 142 are respectively electrically connected to the two ends of the second coil 14. Specifically, the two second connection terminals 142 are both arranged on the outside of the magnetic core 12. In the present embodiment, the two second connection terminals 142 are both arranged on the side of the fourth magnetic core part 124 away from the third magnetic core part 123, and are respectively used as the output terminal and the input terminal of the second coil 14. The first connection terminal 132 and the second connection terminal 142 can be solder balls, and the material can be tin, tin-silver alloy, or tin-lead alloy, etc.

[0023] Further, the transformer 10 further comprises a first solder pad 131 and a second solder pad 141, both located on the side of the first surface 11a of the substrate 11, the first solder pad 131 electrically connecting the first connecting terminal 132 and the first coil 13; the second solder pad 141 electrically connecting the second connecting terminal 142 and the second coil 14. In the embodiment, the first solder pad 131 and the second solder pad 141 are both located on the side of the first dielectric layer 15 away from the substrate 11, for increasing the contact area with the first connecting terminal 132 and the second connecting terminal 142. The material of the first solder pad 131 and the second solder pad 141 is the same as the material of the first coil 13 and the second coil 14.

[0024] Further, the transformer 10 further comprises a first protective layer 17 and a second protective layer 18, the first protective layer 17 is arranged on the side of the first surface 11a of the substrate 11, the first connecting terminal 132 and the second connecting terminal 142 both penetrate and protrude the first protective layer 17, wherein the orthographic projection of the first protective layer 17 on the substrate 11 covers the substrate 11, in the embodiment, the first protective layer 17 covers the first dielectric layer 15, the first solder pad 131, the second solder pad 141 and the magnetic core 12; the second protective layer 18 is arranged on the side of the second surface 11b of the substrate 11, the orthographic projection of the second protective layer 18 on the substrate 11 covers the substrate 11, the second protective layer 18 covers the second dielectric layer 16 and the magnetic core 12; the first protective layer 17 and the second protective layer 18 are used for protecting the first dielectric layer 15, the second dielectric layer 16, the first solder pad 131, the second solder pad 141 and the magnetic core 12. The material of the first protective layer 17 and the second protective layer 18 can be polyimide or the like. In other embodiments, the first connecting terminal 132, the second connecting terminal 142, the first solder pad 131 and the second solder pad 141 can be arranged on the side of the second surface 11b of the substrate 11.

[0025] Optionally, referring to Figure 3 , Figure 3 is a structural schematic diagram of another embodiment of the transformer of the present application. The difference between the embodiment and the previous embodiment is that part of the second magnetic core portion 122 is embedded in the side of the second surface 11b of the substrate 11, the embodiment utilizes the part of the substrate 11 which is not penetrated by the first coil slot 111 and the second coil slot 112, which can be used for embedding the second magnetic core portion 122, the structure improves the compactness of the structure of the transformer 10, and is conducive to realizing the miniaturization of the size of the transformer 10.

[0026] Optionally, referring to Figure 4 and Figure 5 , Figure 4 is a structural schematic diagram of another embodiment of the transformer of the present application, Figure 5 is Figure 4A cross-sectional view along the BB direction. The first coil 13 and the second coil 14 are alternately wound around the third magnetic core 123. In this embodiment, both the first coil 13 and the second coil 14 are spirally wound around the third magnetic core 123 from the inside out in the same direction. A portion of the first coil 13 and the second coil 14 are located on the side of the third magnetic core 123 opposite to the fourth magnetic core 124, while the remaining portion of the first coil 13 and the second coil 14 is located between the third magnetic core 123 and the fourth magnetic core 124. Since the number of turns of the first coil 13 is greater than that of the second coil 14, to improve space utilization, the inner end of the first coil 13 near the third magnetic core 123 can be positioned closer to the third magnetic core 123 than the inner end of the second coil 14, and the outer end of the first coil 13 away from the third magnetic core 123 can be positioned further away from the third magnetic core 123 than the outer end of the second coil 14. That is, in the direction from the third magnetic core 123 to the fourth magnetic core 124, the first connecting terminal 132, the second connecting terminal 142, another second connecting terminal 142, and another first connecting terminal 132 are sequentially arranged. Specifically, both first connecting terminals 132 and both second connecting terminals 142 are located on the outer side of the magnetic core 12. In this embodiment, both first connecting terminals 132 and both second connecting terminals 142 are located on the side of the third magnetic core 123 away from the fourth magnetic core 124. In other embodiments, the first coil 13 and the second coil 14 can also be wound around the fourth magnetic core 124. The above arrangement makes the first coil slot 111 and the second coil slot 112 more closely distributed, which can fill metal in more efficiently to form the first coil 13 and the second coil 14.

[0027] Alternatively, see [link to relevant documentation] Figure 6 , Figure 6 This is a schematic diagram of another embodiment of the transformer described in this application. Figure 1 Compared to the illustrated embodiment, the difference lies in that the first coil groove 111 is connected to the second surface 11b, and the second coil groove 112 is connected to the second surface 11b. In this embodiment, both the first coil groove 111 and the second coil groove 112 penetrate the substrate 11 along the thickness direction (Z direction in the figure), that is, both the first coil 13 and the second coil 14 penetrate the substrate 11 along the thickness direction. Since the maximum thickness of the substrate 11 can reach 200 μm, and the maximum aperture of the first coil groove 111 and the second coil groove 112 can reach 30 μm, the maximum cross-section of the first coil 13 and the second coil 14 can reach 200*30 μm. 2 This further expands the cross-section of the coil, reduces its resistance, and increases the current flowing through the coil, thus enabling the transformer to be used in higher power circuits in a smaller size.

[0028] See Figures 7a-7h , Figures 7a-7his a structural schematic diagram of each step of the preparation method of the transformer of the present application. The transformer 10 provided by the present application is prepared according to the following steps:

[0029] First, as shown in Figure 7a , a first coil groove 111, a second coil groove 112 and two magnetic core grooves 113 are formed on the substrate 11, wherein the first coil groove 111 and the second coil groove 112 respectively surround the two magnetic core grooves 113. The manufacturing process can be laser etching, laser-induced etching, deep ion reaction etching, etc., the aperture can be 5-30 μm (for example, 10, 15, 20 μm, etc.), and the hole depth can be 50-200 μm (for example, 80, 120, 160 μm, etc.). The aperture and the hole depth of the first coil groove 111 and the second coil groove 112 can be different from those of the magnetic core groove 113, or can be the same.

[0030] After filling the glue layer in the two magnetic core grooves 113, an insulating layer (the material can be silicon dioxide SiO2, silicon tetranitride Si3N4, etc.), a seed layer (the material can be titanium copper TiCu, titanium tungsten copper TiWCu, etc.) and a metal layer (the material can be copper, etc.) are sequentially deposited in the first coil groove 111 and the second coil groove 112, the height of the metal layer exceeds the first coil groove 111 and the second coil groove 112, and covers the first surface 11a, then the metal of the first surface 11a is removed by chemical mechanical grinding (CMP) to form the first coil 13 and the second coil 14, as shown in Figure 7b .

[0031] After removing the glue layer in the magnetic core groove 113, the magnetic core material is deposited in the magnetic core groove 113, the height exceeds the first surface 11a, then the magnetic core material of the first surface 11a is removed by chemical mechanical grinding to form the third magnetic core part 123 and the fourth magnetic core part 124, as shown in Figure 7c .

[0032] As shown in Figure 7d , the first dielectric layer 15 is formed on the first surface 11a, and the first dielectric layer 15 is removed at the corresponding third magnetic core part 123, fourth magnetic core part 124, inner and outer ends of the first coil 13 and inner and outer ends of the second coil 14 to form a plurality of first windows 151. The material of the first dielectric layer 15 can be polyimide, which is formed by gluing, photoetching and developing, or can be prepared by vapor deposition of silicon dioxide.

[0033] As shown in Figure 7eAs shown, the first magnetic core part 121, the two first pads 131 and the two second pads 141 are formed on the side of the first dielectric layer 15 away from the substrate 11, and the two ends of the first magnetic core part 121 are connected to the third magnetic core part 123 and the fourth magnetic core part 124 through the first window 151 respectively, the two first pads 131 are connected to the two ends of the first coil 13 through the first window 151 respectively, and the two second pads 141 are connected to the two ends of the second coil 14 through the first window 151 respectively.

[0034] As shown, Figure 7f As shown, the first protective layer 17 is formed on the side of the first dielectric layer 15 away from the substrate 11, the first protective layer 17 covers the first dielectric layer 15 and the first magnetic core part 121, and a plurality of second windows 171 are formed on the first dielectric layer 15 corresponding to the first pad 131 and the second pad 141, two first connecting terminals 132 are formed in the second window 171 to electrically connect the first pad 131, and two second connecting terminals 142 are formed to electrically connect the second pad 141. The first connecting terminal 132 and the second connecting terminal 142 can be solder balls formed by electroplating, printing or ball planting and reflow.

[0035] As shown, Figure 7g As shown, the temporary bonding glue 172 is coated on the side of the first protective layer 17 away from the substrate 11, and then the temporary bonding wafer 173 is bonded thereon. The temporary bonding wafer 173 is used to protect the front surface of the transformer 10, and facilitate the subsequent preparation of the back surface of the transformer 10.

[0036] As shown, Figure 7h As shown, the transformer is turned over, the temporary bonding wafer 173 is downward, and then the side of the substrate 11 away from the first surface 11a is thinned to form a second surface 11b, at this time, the first coil 13 and the second coil 14 can be exposed to the second surface 11b, that is, through the substrate 11, or the first coil 13 and the second coil 14 can not pass through the substrate 11. Then, a second magnetic core part (not shown), a second dielectric layer and a second protective layer are sequentially formed on the second surface 11b, the forming method is as described above for the first magnetic core part, the first dielectric layer and the first protective layer, and the transformer 10 as shown in Figure 1 is formed. The preparation method of the transformer structure of other embodiments is similar to the present embodiment, and will not be described in detail. The present application can use the method of forming a groove, a hole structure on the substrate 11 to make a coil and a part of the magnetic core 12, and making the magnetic core 12 on the front surface of the substrate 11 and the back surface of the substrate, which are completed in the dimension of the substrate 11, without the need to separately make the magnetic core 12 and then combine it with the coil to form the transformer 10, so that the process integration is high and the flow is simplified.

[0037] The application also provides an electronic device comprising the transformer in any of the embodiments. The electronic device can comprise an electromagnetic device, etc. The structure of the application can fully utilize the overall thickness of the transformer 10 device, and realize the increase of the thickness of the first coil 13 and the second coil 14 without increasing the size of the transformer 10 device, thereby increasing the cross section of the coil, reducing the resistance of the coil, and increasing the current through the coil due to the reduction of the resistance of the coil, so that the transformer 10 can adapt to a high-power circuit. On the other hand, the integration of the magnetic core 12, the first coil 13, the second coil 14 and the substrate 11 is high, and the process flow is simple and efficient.

[0038] The above is only an embodiment of the application, and does not limit the patent scope of the application. Any equivalent structure or equivalent process transformation using the content of the specification and drawings, or direct or indirect application in other related technical fields, is also included in the patent protection scope of the application.

Claims

1. A transformer, characterized by The transformer comprises: a substrate comprising a first surface and a second surface arranged oppositely; a magnetic core, at least part of which is located in the substrate, the magnetic core comprising a first magnetic core portion located on one side of the first surface of the substrate, a second magnetic core portion located on one side of the second surface of the substrate, a third magnetic core portion penetrating the substrate, and a fourth magnetic core portion penetrating the substrate and arranged spaced apart from the third magnetic core portion, the third magnetic core portion and the fourth magnetic core portion being arranged spaced apart along a first direction, one end of the third magnetic core portion and the fourth magnetic core portion being connected to the first magnetic core portion, and the other end of the third magnetic core portion and the fourth magnetic core portion being connected to the second magnetic core portion; wherein the substrate is provided with a first coil slot and a second coil slot, the first coil slot and the second coil slot both penetrating the first surface, the first coil slot and the second coil slot both penetrating the second surface, and the first coil slot and the second coil slot both extending around in the extension plane of the substrate; a first coil located in the first coil slot and surrounding the magnetic core, the first coil gradually surrounding the third magnetic core portion from inside to outside and the first coil being arranged without intersection; a second coil located in the second coil slot and surrounding the magnetic core, the second coil gradually surrounding the fourth magnetic core portion from inside to outside and the second coil being arranged without intersection; a first dielectric layer arranged between the substrate and the first magnetic core portion, the third magnetic core portion and the fourth magnetic core portion both penetrating the first dielectric layer, one side of the first dielectric layer away from the substrate being provided with a first pad and a second pad, the first pad being electrically connected to the first coil, and the second pad being electrically connected to the second coil; a second dielectric layer arranged between the substrate and the second magnetic core portion, the third magnetic core portion and the fourth magnetic core portion both penetrating the second dielectric layer; two first connection terminals located on one side of the first surface of the substrate, the two first connection terminals being respectively electrically connected to two ends of the first coil, and along the first direction, the two first connection terminals are both located on one side of the third magnetic core portion away from the fourth magnetic core portion; two second connection terminals located on one side of the first surface of the substrate, the two second connection terminals being respectively electrically connected to two ends of the second coil, and along the first direction, the two second connection terminals are both located on one side of the fourth magnetic core portion away from the third magnetic core portion; a first protective layer arranged on one side of the first dielectric layer away from the first surface, the first connection terminals and the second connection terminals both penetrating and protruding from the first protective layer, wherein the orthographic projection of the first protective layer on the substrate covers the substrate, and the first magnetic core portion is located in the first protective layer; a second protective layer arranged on one side of the second dielectric layer away from the second surface, the orthographic projection of the second protective layer on the substrate covering the substrate, and the second magnetic core portion being located in the second protective layer.

2. The transformer according to claim 1, wherein The substrate is at least one of silicon, glass, or a printed circuit board.

3. Transformer according to claim 2, characterized in that The substrate is a wafer, the first surface is a functional surface of the wafer, or the first surface is a non-functional surface of the wafer.

4. An electronic device, comprising: Transformer according to any one of claims 1 to 3.

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