CN116580940A

CN116580940A - Coil inductor and manufacturing method thereof

Info

Publication number: CN116580940A
Application number: CN202310776578.5A
Authority: CN
Inventors: 刘雪松; 吴家辉
Original assignee: Inmicro Xiamen Microelectronic Technology Co ltd
Current assignee: Inmicro Xiamen Microelectronic Technology Co ltd
Priority date: 2023-06-28
Filing date: 2023-06-28
Publication date: 2023-08-11

Abstract

The invention provides a coil inductor and a manufacturing method thereof, wherein the coil inductor comprises an inductor main body and a magnet coated outside the inductor main body, the inductor main body comprises a coil body, a down-lead part and a bottom electrode, the coil body comprises a plurality of conductive coils which are conducted, the coil body is provided with a first end and a second end, and the first end and the second end are a current flowing-in end and a current flowing-out end of the coil body; the lower guide pieces are arranged in two and correspond to the first ends and the second ends one by one, are parallel to the axis of the coil body and extend towards the same direction; the bottom electrode is provided with two, respectively located the other end of each downlead, and the terminal surface of bottom surface electrode is leveled with the terminal surface of magnet. The two ends of the coil body of the coil inductor are conducted to the bottom electrode through the lower lead body, so that the coil inductor is convenient for a patch mounting mode, and the mounting efficiency of the coil inductor is greatly optimized.

Description

Coil inductor and manufacturing method thereof

Technical Field

The invention relates to the technical field of electronic components, in particular to a coil inductor and a manufacturing method thereof.

Background

An inductor is a component capable of converting bar electric energy into magnetic energy for storage, and a common power inductor is formed by winding a wire with a circular or direct section into a spiral shape, wherein two ends of the wire are exposed from two ends or side surfaces of two ends. With the development of diversification and miniaturization of product requirements, space utilization of electronic components is increasing as a goal of practitioner effort, and therefore, power inductance of bottom electrode is becoming a mainstream of device requirements nowadays.

Disclosure of Invention

In order to solve the problems, the invention is realized by the following technical scheme:

a coil inductor comprising an inductor body and a magnet wrapped outside the inductor body, the inductor body comprising:

the coil body comprises a plurality of conductive coils which are conducted, the coil body is provided with a first end and a second end, and the first end and the second end are a flowing-in end and a flowing-out end of current flowing through the coil body;

the lower guide pieces are provided with two lower guide pieces, correspond to the first ends and the second ends one by one, are parallel to the axis of the coil body and extend towards the same direction;

the bottom electrode is provided with two bottom electrodes which are respectively positioned at the other end of each lower guide piece, and the end face of the bottom electrode is leveled with the end face of the magnet.

Further, the coil body includes:

a plurality of conductive coils;

a plurality of insulating films, wherein the insulating films and the conductive coil are stacked at intervals along a first direction; each insulating film comprises at least one first through hole, and the first through holes on adjacent insulating films are distributed in a staggered manner; and

and the contacts are arranged in each first through hole so as to enable the conductive coils positioned at the two sides of the through holes to be in electrical contact.

Further, the down-guide includes:

a plurality of lower guide rings;

a plurality of insulating films, wherein the insulating films and the conductive coil are stacked at intervals along a first direction; each insulating film comprises a second through hole, and the second through holes on adjacent insulating films are aligned; and

and the contacts are arranged in each second through hole so as to enable the down-lead rings positioned at the two sides of the through holes to be in electric contact.

A method of manufacturing a coil inductor, comprising the steps of:

alternately laying the conductive layers and the insulating layers along the first direction, and forming a required shape by photoetching and/or etching each layer laid; thereby forming a plurality of inductor bodies arranged in an array, wherein the inductor bodies comprise two bottom electrodes, a lower guide piece respectively communicated with the bottom electrodes and a coil body communicated with the other end of the lower guide piece;

arranging the bottom electrodes of a plurality of inductor main bodies arranged in an array downwards and horizontally placing in a mold, and introducing magnetic materials into the mold to cover the inductor main bodies to form an inductor group;

the inductor groups are cut to form a plurality of coil inductors, each coil inductor including one of the coil bodies and a magnet encasing the inductor body.

Compared with the prior art, the technical scheme of the invention has the following beneficial effects:

(1) According to the coil inductor, the two ends of the coil body are conducted to the bottom electrode through the lower guide piece, when the counter electrode is welded to the circuit board in a downward guiding mode, solder paste only exists under the electrode, the occupied area is smaller, the arrangement of chips and components on the circuit board can be denser, meanwhile, the electrodes are located on the same side, so that the coil inductor is convenient to mount in a surface mounting mode, and the mounting efficiency of the coil inductor is greatly optimized.

(2) According to the invention, each layer is subjected to photoetching/etching into a required pattern by stacking the conductive layers and the insulation layers, the inductor group with two electrodes positioned on the bottom surface is formed after stacking, and then the inductor group is subjected to magnetic material forming and cutting, so that the mass production of the inductor is realized, and the production efficiency of the inductor, especially the inductor with the bottom surface electrode, is greatly improved.

Drawings

Fig. 1 is a perspective view of a coil inductor according to an embodiment of the present invention;

fig. 2 is a front view of an inductor body provided by an embodiment of the present invention;

fig. 3 to 18 are steps of forming an inductor body according to an embodiment of the present invention, wherein (a) is a top view and (b) is a front view.

Illustration of:

magnet-100;

an inductor body-200;

a coil body-210; a first coil-211; a second coil-212; a third coil-213; fourth coil-214; a fifth coil-215; a sixth coil-216; seventh coil-217;

a first via-218 (contact 218a between the first conductive coil and the second conductive coil, contact 218b between the second conductive coil and the third conductive coil, contact 218c between the third conductive coil and the fourth conductive coil, contact 218d between the fourth conductive coil and the fifth conductive coil, contact 218e between the fifth conductive coil and the sixth conductive coil, contact 218f between the sixth conductive coil and the seventh conductive coil);

an insulating layer-219;

a first downlead-220;

second via-221 (contact 221x under the first conductive coil, contact 221a with contact 218a flush, contact 221b with contact 218b flush, contact 221c with contact 218c flush, contact 221d with contact 218d flush, contact 221e with contact 218e flush, contact 221f with contact 218f flush);

lower lead ring-222 (lower lead ring under first conductive coil 222x, lower lead ring first conductive coil 222a, lower lead ring second conductive coil 222b, lower lead ring third conductive coil 222c, lower lead ring fourth conductive coil 222d, lower lead ring fifth conductive coil 222e, lower lead ring sixth conductive coil 222 f);

second downlead-230;

a first electrode tip-240; and a second electrode terminal 250.

Detailed Description

For the purpose of making the objects, technical solutions and advantages of the embodiments of the present invention more apparent, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention, and it is apparent that the described embodiments are some embodiments of the present invention, but not all embodiments of the present invention. It should be understood that the specific embodiments described herein are for purposes of illustration only and are not intended to limit the scope of the invention. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.

Fig. 1 illustrates a perspective view of an exemplary coil inductor according to some aspects of the present disclosure, and fig. 2 illustrates a front view of an exemplary inductor body 100 according to some aspects of the present disclosure.

Referring to fig. 1, a coil inductor includes an inductor body 200 and a magnet 100 wrapped around the inductor body. The magnet 100 may be formed from a mixture of magnetic alloy powders including, but not limited to, various types of soft magnetic metal alloys such as iron silicon, iron silicon chromium, iron nickel, iron silicon aluminum, and the like, and a binder.

Referring to fig. 2, the inductor body 200 includes a coil body 210, a down conductor, and a bottom electrode.

The coil body 210 includes a plurality of conductive coils, and has a first end 201 and a second end 202, and when a current flows through the coil body 210, the current flows from the first end 201 into the conductive coils, and flows from the second end 202 after being conducted, i.e. the first end 201 and the second end 202 are electrode ends of the coil body 210.

The two lower lead bodies are respectively corresponding to the first end 201 and the second end 202 one by one, in this embodiment, the first lower lead body 220 corresponds to the first end 201, and the second lower lead body 230 corresponds to the second end 202. The first and second downlead bodies 220 and 230 extend in parallel with the axial direction of the coil body 210 and in the same direction, thereby guiding the electrode terminals of the coil body 210 to the same side.

In this embodiment, the first bottom electrode 240 is correspondingly disposed at an end of the first lower lead 220 away from the coil body 210, and the second bottom electrode 250 is correspondingly disposed at an end of the second lower lead 230 away from the coil body 210. When the coil inductor is in operation, current flows in from the end of the first bottom electrode 240, flows through the first down conductor 220, enters the coil body 210 through the first end 201, flows out of the coil body 210 from the second end 202, and is conducted through the second down conductor 230 to the second bottom electrode 250. The end surfaces of the first bottom electrode 240 and the second bottom electrode 250 are positioned on the same plane with the end surface of the magnet 100, thereby realizing coil inductance patch mounting. It will be appreciated that the end surfaces of the bottom electrode are parallel to the cross-section of the coil body 210, so that the shaped coil inductor is a regular body, such as a cylinder or a square body.

With continued reference to fig. 2, the coil body 210 includes a plurality of conductive coils and a plurality of insulating films stacked at intervals along a first direction, each of the insulating films includes a first through hole 218, a contact is disposed in the first through hole 218, and the conductive coils located on two sides of the same first through hole 218 are electrically connected through the contact. Misalignment between adjacent first vias 218 prevents shorting to the conductive coil in the middle.

Referring to fig. 6 to 18, the present embodiment will be described using an inductor having seven layers of conductive coils as an example, that is, an insulating film 219 is provided between the first conductive coil 211 and the second conductive coil 212, between the third conductive coil 213 and the fourth conductive coil 214, between the fifth conductive coil 215 and the sixth conductive coil 216, between the sixth conductive coil 216 and the seventh conductive coil 217, a contact is provided in the first through hole 218 of each insulating film 219, and the adjacent contacts are not aligned. It will be appreciated that the inductor body may be constructed with more or less than five layers of conductive coils depending on the actual production and use.

The current path of the inductor may enter the first conductive coil 211 from the first end 201, flow through the first conductive coil 211 and the contact 218a into the second conductive coil 212. The current path then enters the third conductive coil 213 through the second conductive coil 212 and the contact 218b and so on, flows through to the seventh conductive coil 217, and then exits at the end of the seventh conductive coil, i.e., the second end 202. Conversely, the current path may flow in from the end of the seventh conductive coil and out from the start of the first conductive coil.

The conductive coil may be formed of a metal, such as copper foil. The insulating film is formed of a non-conductive material, such as a polyimide film, and has a thickness of 5 μm to 50 μm. Each conductive coil may be a toroidal coil, square coil, oval coil, T-coil, and other suitable shapes. Each of the conductive coils mentioned in this embodiment may include a conductive film or a plurality of conductive films stacked along the first direction, the conductive films may be copper films, and adjacent conductive films may be bonded by an adhesive layer or a copper bonding operation, so as to form conductive coils with different thicknesses.

With continued reference to fig. 2, the down-lead member includes a plurality of down-lead rings 222 stacked with a plurality of insulating films at intervals in a first direction, each insulating film includes a second through hole 221, and the second through holes 221 on adjacent insulating films are aligned, a contact is disposed in each second through hole 221, and the down-lead rings 222 on both sides of the same second through hole 221 are electrically contacted through the contact. The down-lead may be formed of metal, such as copper foil, with the down-lead introducing current from one end and transmitting it in a straight line to the other end. The first end 201 is in linear communication with the first bottom surface low stage 240 via the first down conductor 220, and the second end 202 is in linear communication with the second bottom surface low stage 250 via the second down conductor 230.

The embodiment also provides a manufacturing process of the coil inductor, the coil inductor is alternately paved along the first direction through the conductive layer and the insulating layer, each paved layer is formed into a required shape through photoetching and/or etching, so that a plurality of inductor bodies arranged in an array are formed, a plurality of inductor bodies arranged in an array are covered with magnetic materials to form magnets, and the magnets are uniformly cut. More specific steps are as follows.

Fig. 3-18 illustrate plan views and manufacturing process schematics of different layers of a coil inductor body 100 according to some aspects of the present disclosure.

As shown in fig. 3, the underlying conductive layer forms an arbitrary image by photolithography and/or etching, the image being bottom electrodes of the inductor bodies, each inductor body including two bottom electrodes, a first bottom electrode 240 and a second bottom electrode 250, respectively. It will be appreciated that a plurality of bottom electrode pairs arranged in an array may be lithographically formed on the same conductive layer, and the same applies to the later steps herein, each layer being formed in batches with a plurality of desired structures. The present embodiment shows only the formation process of one inductor body, and actually forms a plurality of inductor bodies arranged in an array in batch.

As shown in fig. 4, second through holes 221 are formed in the insulating layer adjacent to the upper side of the bottom electrode, the second through holes 221 are in one-to-one correspondence with the bottom electrodes, and contacts 221x are disposed in the second through holes 221, that is, contacts 221x are disposed on the first bottom electrode 240, and contacts 221x are disposed on the second bottom electrode 250.

The adjacent conductive layer over contact 221x is lithographically and/or etched to form down-lead 222x, which down-lead 222x corresponds to contact 221x, as shown in fig. 5. In this embodiment, the first down-lead 230 is only provided with one layer of contact 221x and one layer of down-lead 222x, and the first down-lead 230 may also include two or more layers of insulation layers and down-lead rings according to practical design and production.

As shown in fig. 6, the conductive layer over contact 221x is lithographically and/or etched to form first conductive coil 211 and down leg 222a, with first conductive coil 211 being in electrical contact with down leg 222 a. The first conductive coil 211 is in contact with one of the down lead rings 222, and the down lead ring 222a is in contact with the other lead ring 222.

The insulating layer on the first conductive coil 211 is provided with a first through hole and a second through hole, the first through hole of the layer is provided with a contact 218a, the second through hole is provided with a contact 221a, the contact 218a is dislocated with the lower lead ring 222x, and the contact 221a is located above the other lower lead ring 222x, as shown in fig. 7.

A conductive layer is continued over the insulating layer containing contact 218a and contact 221a and is lithographically and/or etched to form second conductive coil 212 and down-lead 222b, second conductive coil 212 being in contact with contact 218a and down-lead 222b corresponding to contact 221a, as shown in fig. 8.

An insulating layer is laid over the second conductive coil 212 and the down-lead 222b, the insulating layer having a first via and a second via, the first via of the layer having a contact 218b disposed therein, the second via having a contact 221b disposed therein, the contact 218a being offset from the contact 218b, the contact 221b being located over the down-lead 222b and aligned with the contact 221a, as shown in fig. 9.

A conductive layer is further laid on the insulating layer including the contact 218b and the contact 221b, and the conductive layer is subjected to photolithography and/or etching to form a third conductive coil 213 and a lower lead 222c, wherein the third conductive coil 213 is in contact with the contact 218b, and the lower lead 222c corresponds to the contact 221b, as shown in fig. 10.

An insulating layer is laid over the third conductive coil 213 and the down-lead 222c, the insulating layer having a first via and a second via, the first via of the layer having a contact 218c disposed therein, the second via having a contact 221c disposed therein, the contact 218c being offset from the contact 218b, the contact 221c being located over the down-lead 222c and aligned with the contact 221b, as shown in fig. 11.

A conductive layer is further deposited over the insulating layer including contact 218c and contact 221c and is patterned and/or etched to form a fourth conductive coil 214 and a down-lead 222d, the fourth conductive coil 214 being in contact with contact 218c and the down-lead 222d corresponding to contact 221c, as shown in fig. 12.

An insulating layer is laid over the fourth conductive coil 214 and the down-lead 222d, the insulating layer having a first via and a second via, the first via of the layer having a contact 218d disposed therein, the second via having a contact 221d disposed therein, the contact 218d being offset from the contact 218c, the contact 221d being located over the down-lead 222d and aligned with the contact 221c, as shown in fig. 13.

A conductive layer is further laid on the insulating layer including the contact 218d and the contact 221d, and the conductive layer is lithographically and/or etched to form a fifth conductive coil 215 and a lower lead 222e, the fifth conductive coil 215 being in contact with the contact 218d, the lower lead 222e corresponding to the contact 221d, as shown in fig. 14.

An insulating layer is laid over the fifth conductive coil 215 and the down-lead 222e, the insulating layer having a first via and a second via, the first via of the layer having a contact 218e disposed therein, the second via having a contact 221e disposed therein, the contact 218e being offset from the contact 218d, the contact 221e being located over the down-lead 222e and aligned with the contact 221d, as shown in fig. 15.

A conductive layer is further deposited on the insulating layer including the contact 218e and the contact 221e, and the conductive layer is patterned by photolithography and/or etching to form a sixth conductive coil 216 and a lower lead 222f, wherein the sixth conductive coil 216 contacts the contact 218e, and the lower lead 222f corresponds to the contact 221e, as shown in fig. 16.

An insulating layer is laid over the sixth conductive coil 216 and the down-lead 222f, the insulating layer having a first via and a second via, the first via of the layer having a contact 218f disposed therein, the second via having a contact 221f disposed therein, the contact 218f being offset from the contact 218e, the contact 221f being located over the down-lead 222f and aligned with the contact 221e, as shown in fig. 17.

A conductive layer is continued over the insulating layer containing contact 218f and contact 221f and is lithographically and/or etched to form a seventh conductive coil 217, the seventh conductive coil 217 being in contact with contact 218f and the end of the seventh conductive coil 217 extending over contact 221f to form second end 202, as shown in fig. 18.

Thus, a plurality of inductor main bodies arranged in an array are formed.

The bottom electrode of the array of inductor bodies is placed down and horizontally into a mold, and magnetic material is introduced into the mold to cover all of the inductor bodies, forming the inductor group.

Placing the electrode tip down and horizontally in the mold is understood to mean that the electrode tip is in abutting contact with the bottom of the mold. After the magnetic material is introduced into the die, the magnetic material wraps the inductor body, and the electrode end part attached to the bottom of the die is not covered by the magnetic material, so that all electrode ends of the finally formed inductor group are exposed out of the magnet to form a bottom electrode. It will be appreciated that the magnetic material is infiltrated between the individual electrode tips and the bottom of the mold, and that the electrode tips are also very close to the surface of the magnet, which can be revealed by shallow grinding.

The magnetic material includes a magnetic alloy powder and a binder, and in some embodiments, the magnetic alloy powder includes, but is not limited to, various types of soft magnetic metal alloys such as ferrosilicon, ferrosilicon chromium, ferronickel, ferrosilicon, and the like.

The compression operation may also be performed on the magnetic alloy mixture by a soft medium to compress the magnetic alloy mixture into a magnet. While the soft media may include a magnetic alloy mixture, compressing the magnetic alloy mixture to the magnet; alternatively, the soft medium may be a liquid medium, such as water.

It is also possible to perform a planarization operation on the surface of the magnet to improve the roughness of the surface roughened magnet surface after the soft medium compression.

After the planarization operation, a polishing process, for example, polishing the side of the magnet near the electrode end, so that the end of the electrode is completely exposed to the magnet, i.e., the polished end, may be further included.

Thus, an inductor group in which the end face of each bottom electrode is flush with the end face of the magnetic material is obtained.

The inductor groups are cut to form a plurality of coil inductors, each coil inductor including one of the coil bodies and a magnet surrounding the coil body. Therefore, a plurality of coil inductors are obtained at one time, and the production efficiency of the bottom electrode inductor is effectively improved.

While the foregoing description illustrates and describes the preferred embodiments of the present invention, it is to be understood that the invention is not limited to the forms disclosed herein, but is not to be construed as limited to other embodiments, but is capable of use in various other combinations, modifications and environments and is capable of changes or modifications within the scope of the inventive concept, either as described above or as a matter of skill or knowledge in the relevant art. And that modifications and variations which do not depart from the spirit and scope of the invention are intended to be within the scope of the appended claims.

Claims

1. A coil inductor comprising an inductor body and a magnet wrapped around the inductor body, the inductor body comprising:

2. A coil inductor according to claim 1, wherein said coil body comprises:

a plurality of conductive coils;

3. A coil inductor according to claim 1, wherein said down-conductor comprises:

a plurality of lower guide rings;

4. A coil inductor according to claim 2 or 3, wherein the insulating film has a thickness of 5 μm to 50 μm.

5. A coil inductor according to claim 1, wherein the conductive coil comprises one or more layers of conductive film stacked in a first direction.

6. A method of manufacturing a coil inductor, comprising the steps of:

7. The method of manufacturing a coil inductor according to claim 6, wherein the method of forming the electrode terminal comprises: the underlying conductive layer is patterned by photolithography and/or etching to form an arbitrary image, which is the bottom electrode of the inductor body.

8. The method of manufacturing a coil inductor according to claim 6, wherein said method of forming said down-lead comprises:

second through holes are formed in the adjacent insulating layers above the bottom surface electrodes, and the second through holes correspond to the electrode terminals one by one;

the conducting layer positioned on the second through hole forms a first down-lead ring through photoetching and/or etching, the first down-lead ring corresponds to the second through hole, and the first down-lead ring and the electrode terminal are in electric contact through a contact arranged in the second through hole;

the insulating layer above the first lower lead ring is also provided with a second through hole and internally provided with a contact, and the conducting layer above the second through hole forms a second lower lead ring;

and by analogy, two lower guide pieces with different lengths are formed, a lower guide ring positioned above the same bottom electrode and an insulating layer with a second through hole form the lower guide piece, and the second through holes in the same lower guide piece are aligned.

9. The method of manufacturing a coil inductor according to claim 8, wherein the forming method of the coil body includes:

forming a first conductive coil by photoetching and/or etching the conductive layer;

the insulating layer above the first conductive coil comprises a first through hole, and a contact is arranged in the first through hole;

the conductive layer above the first through hole forms a second conductive coil;

the insulating layer above the second conductive coil is also provided with a first through hole and is internally provided with a contact;

the coil body is formed by alternately stacking the conductive coils and the insulating layers by using the conductive coils to the top layer, the adjacent conductive coils are in electric contact through the contacts, and the adjacent first through holes are distributed in a staggered manner;

wherein the first conductive coil is electrically contacted with the upper end of the short down-lead, and the top conductive coil is electrically contacted with the upper end of the long down-lead.

10. A method of manufacturing a coil inductor according to claim 9, characterized in that the electrical coil and the down conductor in the same plane are obtained by lithography and/or etching of the same conductive layer, and that the first and second via layers in the same plane are provided in the same insulating layer.

11. A method of manufacturing a coil inductor according to claim 9 wherein each of said conductive coils is circular, spiral, rectangular, spiral rectangular.