CN111200062B - Miniaturized inductor manufacturing method based on nanoparticle filling process and inductor - Google Patents

Abstract

The invention discloses a miniaturized inductor manufacturing method and inductor based on a nanoparticle filling process, including: a precision magnetic core manufacturing process; three-dimensional interconnection channel etching and filling; a double-sided interconnection structure manufacturing process, etc. The present invention uses microelectronic technology to realize a three-dimensional inductor device with a magnetic core. While miniaturizing the inductor device, it retains a high inductance and solves the problem that the inductance value of the miniaturized inductor cannot be increased. At the same time, it also proposes A new process solution solves the metal filling problem of high aspect ratio micro-grooves and micro-hole structures.

Description

A miniaturized inductor manufacturing method and inductor based on nanoparticle filling process

Technical field

The invention relates to the fields of electronic components, microelectronics process technology and other fields, and specifically relates to a manufacturing method and inductor of a miniaturized inductor with a magnetic core. The invention utilizes microelectronics process technology to realize the production and three-dimensional interconnection of precision magnetic cores, thereby realizing high-capacity Miniaturized capacitor devices.

Background technique

As people's requirements for electronic products develop in the direction of miniaturization and multi-function, people strive to make electronic systems smaller and smaller and more integrated. However, because magnetic materials are not easily compatible with semiconductor processes, magnetic components In the process of miniaturization of electronic equipment, it lags behind the development of other components and cannot achieve a high level of miniaturization.

In order to solve this problem, researchers have developed a variety of processing methods for depositing magnetic core films, such as screen printing, sputtering and electroplating. However, the ferrite layer printed with a screen needs to be sintered at a temperature of 900 to 1000°C, which is incompatible with the standard integrated circuit manufacturing process; the thickness of the magnetic core produced by the sputtering process is limited and the cost is relatively high. High, which limits the industrial development of this technology; the Q value of the inductor of magnetic material cores formed by electroplating is generally lower than the Q value of materials formed by sputtering technology or screen printing technology. The main reason is that the magnetic Caused by the conductivity of the material, when the operating frequency of the inductor increases, the eddy current loss of the magnetic core will increase. In addition to the compatibility between magnetic materials and microelectronic processes, semiconductor processes are generally planar processes and can only realize chip inductors, which greatly limits the performance of the inductor.

Contents of the invention

The main purpose of the present invention is to overcome the problems that the inductance value of a miniaturized inductor cannot be increased and the inductance performance optimization is difficult, and a miniaturized inductor manufacturing method and inductor based on a nanoparticle filling process are proposed.

The present invention adopts the following technical solutions:

A method for manufacturing a miniaturized inductor based on a nanoparticle filling process, which is characterized by including the following steps:

1) Make a magnetic core mold cavity on the first surface of the substrate;

2) Fill the micro-nano-sized magnetic material into the magnetic core mold cavity to make the magnetic material dense to form a magnetic core;

3) Make a longitudinal interconnection structure on the periphery of the magnetic core mold cavity on the first surface of the substrate;

4) Use a thinning process to expose the conductive material on the second surface of the substrate;

5) Make lateral interconnection structures on the first surface and the second surface of the substrate respectively, and the lateral interconnection structure is electrically connected to the vertical interconnection structure to form an inductor coil.

Preferably, the material of the substrate is any one of silicon, germanium, gallium arsenide or indium phosphide, or any one of glass, ceramics or polymer materials.

Preferably, in step 1), ultrasonic drilling, sandblasting, wet etching, dry etching, laser etching or mechanical drilling are used to make a first groove on the substrate, and the first groove is Grooves form the core mold cavity, with a depth ranging from 0.1 microns to 3 millimeters.

Preferably, the cross section of the first groove is rectangular, circular, or zigzag-shaped.

Preferably, step 3) is specifically:

3.1) First use ultrasonic drilling, sandblasting, wet etching, dry etching, laser etching or mechanical drilling to make multiple second grooves on the substrate material;

3.2) Fill the second groove with conductive material;

3.3) Use pressure or ultrasonic vibration to densify the conductive material in the second groove and remove the conductive material outside the second groove.

Preferably, the conductive material is in the form of powder or particles, and is made of one or more of pure copper, copper alloy, pure tin, tin alloy, pure silver, silver alloy, pure aluminum, aluminum alloy, pure gold or gold alloy. kind.

Preferably, step 3) adds a heat treatment step: subjecting the substrate to high temperature treatment in a vacuum environment or under a protective atmosphere of inert gas or reducing gas.

Preferably, in step 5), the horizontal interconnection structure can be made of metal circuits using a screen printing process.

Preferably, the lateral interconnection structure can be made by making a seed layer, applying photoresist on the seed layer and completing photolithography patterning, depositing metal in the area where the photoresist is opened, and removing the photoresist to form a metal interconnection.

A miniaturized three-dimensional inductor based on nanoparticle filling technology, characterized by including a substrate, a magnetic core and an inductor coil; the substrate is provided with a first groove and a number of through holes, the number of through holes are located in the first groove Perimeter; the magnetic core is formed by filling the first groove with micro-nano-sized magnetic material; the through hole is filled with conductive material to form a vertical interconnection structure; the first surface and the second surface of the substrate are respectively provided with lateral interconnections structure, the horizontal interconnection structure and the vertical interconnection structure are electrically connected to form an inductor coil.

From the above description of the present invention, it can be seen that compared with the prior art, the present invention has the following beneficial effects:

1. The method of the present invention uses microelectronics technology to realize a three-dimensional inductor device with a magnetic core. While miniaturizing the inductor device, it retains a high inductance and solves the problem that the inductance value of the miniaturized inductor cannot be increased. ; At the same time, a new process solution was also proposed to solve the metal filling problem of high aspect ratio micro-grooves and micro-hole structures.

2. The method of the present invention uses ultrasonic vibration to improve the gap-filling effect of nanoparticles and improve the filling effect of micropores when making longitudinal interconnected structures. Utilize high-temperature treatment under an inert or reducing gas protective atmosphere to improve the microstructure after filling with nanoparticles, suppress the quantum size effect and surface effect of nanoconductive particles, and suppress the small size effect and macroscopic quantum tunneling effect of nanomagnetic materials; improve nanometer Particle filling effect.

3. The method of the present invention uses microelectronics technology to make a first groove to form a magnetic core mold for making a magnetic core; and makes a second groove to form a mold on the substrate to make a vertical interconnection structure and a lateral interconnection structure. , forming an embedded three-dimensional interconnection wire to achieve a highly integrated, large-load micro-capacitor structure.

Description of drawings

Figure 1(a) is a cross-sectional view of the substrate;

Figure 1(b) is a top view of the circular substrate;

Figure 1(c) is a top view of a square substrate;

Figure 2 is a schematic diagram of making the first groove on the substrate;

Figure 3 is a schematic diagram of filling the first groove with magnetic material;

Figure 4 is a schematic diagram of removing the magnetic material outside the first groove;

Figure 5 is a schematic diagram of making a second groove on the substrate;

Figure 6 is a schematic diagram of filling the second groove with conductive material;

Figure 7 is a schematic diagram of removing the conductive material outside the second groove;

Figure 8 is a schematic diagram of making a first surface lateral interconnection structure;

Figure 9 is a schematic diagram of thinning;

Figure 10 is a schematic diagram of the lateral interconnection structure of the second surface of the device;

Figure 11 is a top view of the inductor of the present invention (Embodiment 1);

Figure 12 is a top view of the inductor of the present invention (Embodiment 2);

Figure 13 is a top view of the inductor of the present invention (Embodiment 3);

Among them: 10. Substrate, 11. First groove, 12. Second groove, 20. Magnetic core, 21. Magnetic material, 30. Vertical interconnection structure, 31. Conductive material, 40. Horizontal interconnection structure.

Detailed ways

The present invention will be further described below through specific embodiments.

Embodiment 1

A method for manufacturing a miniaturized inductor based on nanoparticle filling technology, including the following steps:

1) Prepare a material for the substrate 10 , which may be any single crystal semiconductor or compound semiconductor material such as silicon, germanium, gallium arsenide, or indium phosphide, or any insulating material such as glass or ceramic. Referring to FIGS. 1(a) to 1(c) , the substrate 10 can be a circular or square sheet, and a magnetic core mold cavity is made on the first surface of the substrate 10 .

Referring to Figure 2, ultrasonic drilling, sandblasting, wet etching, dry etching, laser etching, mechanical drilling and other processes are used to make a first groove 11 of a specific shape on the substrate 10 as a magnetic core mold. Cavity, depending on the size and model of the inductor device, the size and shape of the first groove may be different. The depth of the first groove 11 may be 0.1 micron to 3 mm, and its cross-section may be rectangular or circular.

2) Fill the magnetic core mold cavity with micro-nano sized magnetic material. The magnetic material can be magnetic powder, particles, magnetic powder and other magnetic materials. The micro-nano size refers to between 10nm and 20um. Select guide nozzles, conduits, etc. to transfer the magnetic material to the substrate surface, see Figure 3 and Figure 4. The magnetic material in the first groove 11 is made dense by pressure, ultrasonic vibration, etc., and then the magnetic material outside the first groove 11 is removed to form the magnetic core 20 .

3) Make a longitudinal interconnection structure 30 on the periphery of the magnetic core mold cavity on the first surface of the substrate 10 , and the longitudinal interconnection structure 30 is not parallel to the first surface and the second surface of the substrate 10 . This step specifically includes the following:

3.1) First use ultrasonic drilling, sandblasting, wet etching, dry etching, laser etching or mechanical drilling to make two sets of second grooves 12 on the first surface of the substrate 10, respectively located in the first groove. Each group is provided with the same number of second grooves 12 on two opposite sides of the groove 11, for example, located on two opposite sides of the rectangular first groove 11, see Figure 5.

3.2) Fill the two sets of second grooves 12 with conductive material 31 . The conductive material 31 can be conductive powder, particles or slurry. The conductive material 31 includes: pure copper, copper alloy, pure tin, tin alloy, pure silver, silver alloy, pure aluminum, aluminum alloy, pure gold or gold alloy, etc. Use pressure, etc. to fill in, see Figure 6.

3.3) Use pressure or ultrasonic vibration to densify the conductive material in the second groove 12, and remove the conductive material 31 outside the second groove 12, see Figure 7.

When the product has high requirements for powder or particle filling, a heat treatment step can be added: in a vacuum environment, you can also choose to perform high-temperature treatment on the substrate 10 under an inert or reducing gas protective atmosphere to make the magnetic materials and conductive materials dense. According to the different requirements of sintering effect, the process temperature range is 150-1200 degrees.

4) A thinning process is used to expose the conductive material 31 on the second surface of the substrate 10. This process can be achieved by back grinding and polishing processes, see Figure 9.

5) Referring to Figures 8 and 10, a horizontal interconnection structure 40 is formed on the first surface and the second surface of the substrate 10 respectively. The horizontal interconnection structure 40 is electrically connected to the vertical interconnection structure 30 to form an inductor coil. The plurality of second grooves 12 in the two groups correspond one to one, and the lateral interconnection structure 40 includes a plurality of metal lines, and each metal line is connected between the corresponding second grooves 12 in the two groups, see FIG. 11 .

The horizontal interconnection structure 40 can be implemented using a variety of methods as follows:

aThe horizontal interconnection structure 40 can be made of metal circuits using a screen printing process.

b Use evaporation or physical vapor deposition process to make a seed layer, apply photoresist on the seed layer and complete photolithography patterning, deposit metal using electroless plating or electroplating process in the area where the photoresist is opened, and finally remove the glue to complete the seed layer The layers are etched to form metal interconnects.

c Use evaporation or physical vapor deposition process to make a seed layer, then use electroless plating or electroplating process to deposit metal, apply photoresist on the metal layer and complete photolithography patterning, remove the metal in the photoresist open area, and finally remove the glue Form metal interconnections.

In step b or c, the material of the seed layer is one or a combination of metals such as titanium, titanium nitride, tantalum, tantalum nitride, copper, and silver. The metal is copper, titanium, nickel, tin, silver, gold. One or a combination of several other metals.

The order of the method steps in the method of the present invention is not limited to this and can be adjusted as needed. The order of the manufacturing and filling steps of the magnetic core mold cavity and the longitudinal interconnection structure 30 can be exchanged. The steps of manufacturing the first groove 11 and the second groove 12 can be changed. Steps can be combined or reversed. The substrate thinning step can be performed after the conductive material 31 is filled, or after the lateral interconnection structure 40 on the first surface of the substrate 10 is formed.

The invention uses microelectronic technology to make a magnetic core mold and uses the magnetic core mold to make an embedded magnetic core; and makes a three-dimensional interconnection structure on a substrate, and uses the three-dimensional interconnection structure as a mold to make embedded three-dimensional interconnection wires, achieving high integration. Micro capacitor structure for large loads. The invention breaks through the bottleneck of microelectronics technology being unable to produce magnetic cores of larger size and thickness, greatly improves the inductor capacity and performance optimization space, and at the same time proposes a process method for realizing a low-cost three-dimensional interconnection structure, which can obtain more The high inductor quality factor and inductance value solve the problem that micro inductors cannot obtain large inductance value, large current load and high quality factor at the same time.

A miniaturized three-dimensional inductor based on nanoparticle filling technology produced by the method of the present invention includes a substrate 10, a magnetic core 20 and an inductor coil. The substrate 10 is provided with a first groove 11 and a plurality of through holes. The first groove 11 is located on the first surface. The plurality of through holes are through holes formed by two groups of second grooves 12 after substrate thinning, and are located on the outer periphery of the first groove 11 .

The magnetic core 20 is formed by filling the first groove 11 with micro-nano-sized magnetic material, and using pressure and ultrasonic vibration to make it dense. The through hole is filled with conductive material 31 to form a vertical interconnection structure 30 . The first surface and the second surface of the substrate 10 are respectively provided with lateral interconnection structures 40, and the lateral interconnection structures 40 are electrically connected to the vertical interconnection structures 30 to form an inductor coil.

Embodiment 2

A method for manufacturing a miniaturized inductor and an inductor based on a nanoparticle filling process. Its main features are the same as those of Embodiment 1. The difference is that the first groove 11 is in the shape of a zigzag, see Figure 12, and a set of second grooves 12 are located in the first embodiment. A groove 11 is located on the inner circumference, and a set of second grooves 12 is located on the outer circumference of the second groove 12 .

Embodiment 3

A miniaturized inductor manufacturing method and inductor based on a nanoparticle filling process, the main features of which are the same as those of Embodiment 1, except that the first groove 11 is annular, see Figure 13, and a set of second grooves 12 are located The first grooves 11 are on the inner circumference and are distributed in a circumferential manner, and a set of second grooves 12 are located on the outer circumference of the second grooves 12 and are also distributed in a circumferential manner.

The above are only specific embodiments of the present invention, but the design concept of the present invention is not limited thereto. Any non-substantive changes to the present invention using this concept shall constitute an infringement of the protection scope of the present invention.

Claims (9)

1. The miniaturized inductor manufacturing method based on the nanoparticle filling process is characterized by comprising the following steps of:

1) Manufacturing a magnetic core die cavity on the first surface of the substrate;

2) Filling a magnetic material with micro-nano size into a magnetic core die cavity, and compacting the magnetic material by using pressure or ultrasonic vibration to form a magnetic core, wherein the micro-nano size of the magnetic material is between 10nm and 20 um;

3) Manufacturing a longitudinal interconnection structure on the periphery of a magnetic core die cavity on the first surface of a substrate, wherein the longitudinal interconnection structure specifically comprises the following steps:

3.1 Firstly, adopting ultrasonic drilling, sand blasting, wet etching, dry etching, laser etching or mechanical drilling to manufacture two groups of second grooves on the substrate material, wherein the two groups of second grooves correspond to each other one by one;

3.2 Filling the second groove with a conductive material;

3.3 The conductive material in the second groove is densified by using pressure or ultrasonic vibration, and the conductive material outside the second groove is removed;

4) A thinning process is adopted to enable the second surface of the substrate to expose the conductive material of the longitudinal interconnection structure;

5) And manufacturing a transverse interconnection structure on the first surface and the second surface of the substrate respectively, wherein the transverse interconnection structure comprises a plurality of metal circuits, each metal circuit is connected between the corresponding second grooves in the two groups, and the transverse interconnection structure is electrically connected with the conductive material of the longitudinal interconnection structure so as to form an inductance coil around the magnetic core.

2. The method of claim 1, wherein the substrate is made of any one of silicon, germanium, gallium arsenide, or indium phosphide, or any one of glass, ceramic, or polymer material.

3. The method of claim 1, wherein in step 1), a first recess is formed in the substrate by ultrasonic drilling, sand blasting, wet etching, dry etching, laser etching, or mechanical drilling, the first recess forming the core cavity and having a depth of 0.1 μm to 3 mm.

4. A miniaturized inductor fabrication method based on nanoparticle filling process as claimed in claim 3, wherein the cross section of the first groove is rectangular or circular or zigzag.

5. The method of claim 1, wherein the conductive material is in the form of powder or particles, and the conductive material is one or more of pure copper, copper alloy, pure tin, tin alloy, pure silver, silver alloy, pure aluminum, aluminum alloy, pure gold, or gold alloy.

6. The miniaturized inductor fabrication method based on nanoparticle filling process of claim 1, wherein said step 3) adds a heat treatment step of: and (3) carrying out high-temperature treatment on the substrate in a vacuum environment or an inert gas or reducing gas protective atmosphere, wherein the process temperature is 150-1200 ℃.

7. The method of claim 1, wherein in step 5), the lateral interconnect structure is formed as a metal line by a screen printing process.

8. The method for fabricating a miniaturized inductor based on a nanoparticle filling process according to claim 1, wherein the lateral interconnection structure is formed by forming a seed layer, coating photoresist on the seed layer and performing photolithographic patterning, depositing metal in an area where the photoresist is opened, and removing the photoresist to form a plurality of metal lines.

9. A miniaturized three-dimensional inductor based on a nanoparticle filling process, which is characterized by being manufactured by adopting the miniaturized inductor manufacturing method based on the nanoparticle filling process, and comprising a substrate, a magnetic core and an inductor coil; the substrate is provided with a first groove and a plurality of through holes, and the through holes are positioned at the periphery of the first groove; the magnetic core is formed by filling a first groove with a magnetic material with a micro-nano size; the through holes are filled with conductive materials to form a longitudinal interconnection structure; the first surface and the second surface of the substrate are respectively provided with a transverse interconnection structure, and the transverse interconnection structure is electrically connected with the longitudinal interconnection structure to form an inductance coil.