On-chip spiral core inductor, its fabrication method and mass production method

Abstract

This application discloses an on-chip spiral core inductor, its fabrication method, and a mass production method. The fabrication method includes: forming a trench structure on a first substrate; forming a core composite structure; and electrically interconnecting the trench structure and the core composite structure. This invention separately fabricates the trench structure on the first substrate, then separately fabricates the core composite structure (which is incompatible with CMOS processes), and finally aligns and electrically interconnects the trench structure and core composite structure on the first substrate using a mass-producible packaging technology. This not only solves the process compatibility problem but also enables mass production of on-chip spiral core inductors, improving device performance.

Description

Technical Field

[0001] This invention relates to the field of integrated circuit manufacturing and packaging technology, and in particular to an on-chip spiral magnetic core inductor, its manufacturing method and mass production method. Background Technology

[0002] With the rapid development of communication technology, modern communication systems have an increasingly strong demand for integration, modularity, and miniaturization. A key challenge in the miniaturization of wireless radio frequency circuits is how to increase the inductance density of integrated inductors. Introducing magnetic materials is one important way to increase inductance; however, the fabrication process of magnetic materials is complex and generally requires high processing temperatures, and there are also incompatibility issues with CMOS processes. This significantly restricts the development of on-chip inductors containing magnetic materials. Compared to the planar spiral inductors commonly used in circuits today, solenoid inductors have a higher quality factor, lower losses, and a smaller area. Although solenoid-type integrated inductors with magnetic cores have better performance, the complexity of their fabrication process and incompatibility limit their large-scale mass production and commercialization. Summary of the Invention

[0003] In view of this, the present invention provides an on-chip spiral core inductor and its manufacturing method and mass production method, which not only solves the process compatibility problem, but also realizes the mass production of on-chip spiral core inductors and improves device performance.

[0004] To achieve the above objectives, the present invention provides the following technical solution:

[0005] A method for fabricating an on-chip spiral core inductor, the method comprising:

[0006] A trench structure is formed on the first substrate;

[0007] Forming a magnetic core composite structure;

[0008] The trench structure and the magnetic core composite structure are electrically interconnected.

[0009] Preferably, in the above manufacturing method, the method for forming the groove structure includes:

[0010] The first substrate is provided, the first substrate having opposing first and second surfaces;

[0011] A patterned barrier layer is formed on the first surface;

[0012] Based on the patterned barrier layer, a trench is formed in the first surface;

[0013] A first metal layer is formed at the bottom of the trench, on the sides, and on a portion of the surface of the barrier layer;

[0014] Contact points are formed on the surfaces of the first metal layer on both sides of the trench.

[0015] Preferably, in the above-described manufacturing method, the method for forming the magnetic core composite structure includes:

[0016] A second substrate is provided, the second substrate having a third surface;

[0017] A sacrificial layer is formed on the third surface;

[0018] A second metal layer is formed on the sacrificial layer away from the third surface;

[0019] A magnetic core structure is formed on the second metal layer away from the surface of the sacrificial layer;

[0020] The sacrificial layer is etched to separate the magnetic core structure and the second metal layer from the second substrate, forming a magnetic core composite structure including the magnetic core structure and the second metal layer.

[0021] Preferably, in the above manufacturing method, the magnetic core structure is a single-layer thin film of magnetic material layer, or a multi-layer composite thin film of alternating magnetic material layer and isolation layer.

[0022] Preferably, in the above manufacturing method, the magnetic material layer is any one of a soft magnetic layer, a hard magnetic alloy layer, and an amorphous metal single-layer thin film;

[0023] The isolation layer is any one of SiO2 layer, Al2O3 layer, HfO2 layer and TiO2 layer.

[0024] Preferably, in the above manufacturing method, the groove structure and the magnetic core composite structure are interconnected by thermo-press welding;

[0025] Alternatively, the trench structure and the magnetic core composite structure may be interconnected by laser welding;

[0026] Alternatively, the trench structure and the magnetic core composite structure may be interconnected by bonding with conductive adhesive.

[0027] Preferably, in the above manufacturing method, the magnetic core composite structure matches the shape of the trench structure so that the magnetic core composite structure is accommodated within the trench structure.

[0028] The present invention also provides an on-chip spiral core inductor prepared by the manufacturing method described in any one of the above claims, the on-chip spiral core inductor comprising:

[0029] Trench structure and magnetic core composite structure for electrical interconnection;

[0030] The trench structure includes: a first substrate having opposing first and second surfaces; a patterned barrier layer disposed on the first surface; a trench formed in the first surface based on the patterned barrier layer; a first metal layer formed at the bottom, sides, and part of the surface of the barrier layer of the trench; and contact points formed on the surfaces of the first metal layer on both sides of the trench.

[0031] The magnetic core composite structure includes: a second metal layer and a magnetic core structure disposed on the surface of the second metal layer.

[0032] This invention also provides a method for mass production of on-chip spiral core inductors, the method comprising:

[0033] Multiple trench structures and multiple magnetic core composite structures were prepared using the above-described fabrication method;

[0034] Multiple magnetic core composite structures and multiple trench structures are electrically interconnected to form multiple on-chip spiral magnetic core inductors.

[0035] Preferably, in the above-described mass production method, the magnetic core composite structure and the groove structure are interconnected by thermo-press welding or by laser welding.

[0036] As described above, the on-chip spiral core inductor and its fabrication method and mass production method provided by the present invention involve separately fabricating a trench structure on a first substrate, then separately fabricating a magnetic core composite structure incompatible with CMOS processes, and finally using packaging technology to align and electrically interconnect the trench structure and magnetic core composite structure on the first substrate. This not only solves the process compatibility problem but also enables mass production of on-chip spiral core inductors, improving device performance. Attached Figure Description

[0037] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0038] Figures 1-15 A process flow diagram of a method for manufacturing an on-chip spiral core inductor provided in an embodiment of the present invention;

[0039] Figure 16 A three-dimensional structural diagram of an on-chip spiral core inductor provided in an embodiment of the present invention;

[0040] Figure 17This is a top view of an on-chip spiral core inductor provided in an embodiment of the present invention;

[0041] Figure 18 and Figure 19 This is a schematic diagram illustrating the principle of a mass production method for an on-chip spiral core inductor provided in an embodiment of the present invention. Detailed Implementation

[0042] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0043] To make the above-mentioned objectives, features and advantages of this application more apparent and understandable, the application will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0044] refer to Figures 1-15 , Figures 1-15 A process flow diagram of a method for fabricating an on-chip spiral core inductor provided in an embodiment of the present invention, the method comprising:

[0045] Step S11: As Figures 1-9 As shown, a trench structure 200 is formed on the first substrate 201;

[0046] In this embodiment of the invention, the method for forming the trench structure 200 includes:

[0047] Step S21: As Figure 1 As shown, a first substrate 201 is provided, the first substrate 201 having opposing first and second surfaces; wherein, the first substrate 201 may be a silicon substrate or other semiconductor substrate, such as Ge, GaAs, etc.

[0048] Step S22: As Figure 2 As shown, a barrier layer 202 is formed on the first surface and the second surface; the barrier layer 202 can be formed by a deposition process, and the barrier layer 202 can be SiO2 or other materials, such as alumina.

[0049] Step S23: As Figures 3-6 As shown, a patterned barrier layer 202 is formed on the first surface;

[0050] Before forming the patterned barrier layer 202, firstly, as... Figure 3 As shown, a photoresist layer 203 is spin-coated onto the barrier layer 202 away from the first surface; then, as... Figure 4 As shown, a mask photolithography pattern is applied to the photoresist layer 203 to form a patterned photoresist layer 203, exposing a portion of the barrier layer 202; then, as... Figure 5 As shown, based on the patterned photoresist layer 203, the barrier layer 202 on the first surface is etched to form the patterned barrier layer 202; finally, as... Figure 6 As shown, the photoresist layer 203 is removed.

[0051] Step S23: As Figure 7 As shown, based on the patterned barrier layer 202, a trench 204 is formed in the first surface;

[0052] The trench 204 can be formed on the first surface by photolithography. The shape of the trench 204 can be determined according to the structure of the designed inductor or transformer. From the top view, the opening shape of the trench 204 can be polygonal, circular, or elliptical, etc.

[0053] Step S24: As Figure 8 As shown, a first metal layer 205 is formed at the bottom, sides and part of the surface of the barrier layer 202 of the trench 204; the material of the first metal layer 205 may be copper, gold, aluminum, tungsten or other conductive materials.

[0054] Step S25: As Figure 9 As shown, contact points 206 are formed on the surfaces of the first metal layer 205 on both sides of the trench 204, and the barrier layer 202 on the second surface is removed. The trench structure 200 can be electrically interconnected with the magnetic core composite structure 300 through the contact points 206.

[0055] Step S12: As Figures 10-14 As shown, a magnetic core composite structure 300 is formed;

[0056] In this embodiment of the invention, the method for forming the magnetic core composite structure 300 includes:

[0057] Step S31: As Figure 10 As shown, a second substrate 301 is provided, the second substrate 301 having a third surface; wherein, the second substrate 301 may be a sapphire substrate or a substrate of other materials.

[0058] Step S32: As Figure 11 As shown, a sacrificial layer 302 is formed on the third surface; the sacrificial layer 302 can be formed by a deposition process, and the sacrificial layer 302 can be, but is not limited to, polyimide, etc.

[0059] Step S33: As Figure 12As shown, a second metal layer 303 is formed on the sacrificial layer 302 away from the third surface; the second metal layer 303 can be formed using photolithography and deposition techniques.

[0060] Before forming the second metal layer 303, a photoresist layer is first spin-coated on the surface of the sacrificial layer 302, then photolithography is performed to form a patterned photoresist layer, exposing part of the sacrificial layer 302. Then, the second metal layer 303 is deposited on the exposed part of the sacrificial layer 302, and finally the photoresist layer is removed.

[0061] Step S34: As Figure 13 As shown, a magnetic core structure 306 is formed on the surface of the second metal layer 303 away from the surface of the sacrificial layer 302; the magnetic core structure 306 can be a single-layer thin film of magnetic material layer 305, or a multi-layer composite thin film of magnetic material layer 305 and isolation layer 304 alternating layers.

[0062] The magnetic material layer can be any one of a soft magnetic layer, a hard magnetic alloy layer, or an amorphous metal monolayer film; the magnetic material layer 305 includes a NiFe layer, a FeCo layer, a CoZrTa layer, a MnZn layer, a NiZn layer, and a BaM layer.

[0063] The isolation layer can be any one of the insulating layers such as SiO2 layer, Al2O3 layer, HfO2 layer and TiO2 layer.

[0064] It should be noted that if the magnetic core structure 306 is a single-layer thin film structure, the magnetic material layer 305 can be formed by pulsed laser deposition, screen printing and baking, or plasma sputtering deposition; if it is a multi-layer composite thin film structure, the magnetic material layer 305 and the isolation layer 304 can be alternately deposited by pulsed laser deposition or plasma sputtering deposition to form a multi-layer composite thin film with alternating magnetic material layer 305 and isolation layer 304.

[0065] It should be noted that the embodiments of the present invention are only described with the magnetic core structure 306 being a multilayer composite thin film structure as an example. In other embodiments, the magnetic core structure can also be described with a single-layer thin film structure as an example, which will not be elaborated here.

[0066] Step S35: As Figure 14 As shown, the sacrificial layer 302 is etched to separate the magnetic core structure 306 and the second metal layer 303 from the second substrate 301, forming a magnetic core composite structure 300 including the magnetic core structure 306 and the second metal layer 303.

[0067] Step S13: As Figure 15 As shown, the trench structure 200 and the magnetic core composite structure 300 are electrically interconnected.

[0068] The contact points 206 of the trench structure 200 on the first substrate 201 are aligned with the corresponding positions of the magnetic core composite structure 300. At the contact points 401 of the two structures, the two structures are electrically interconnected by welding technology, heating and pressurizing, so that the first metal layer 205 and the second metal layer 303 are electrically interconnected to form an on-chip spiral magnetic core inductor.

[0069] In this embodiment of the invention, the trench structure 200 and the magnetic core composite structure 300 can be interconnected by thermo-press welding, laser welding, or conductive adhesive bonding.

[0070] The magnetic core composite structure 300 and the trench structure 200 are shaped and sized to fit together so that the magnetic core composite structure 300 is accommodated within the trench structure 200.

[0071] It should be noted that when the magnetic core composite structure 300 is housed within the trench structure 200, a gap may be reserved between the magnetic core composite structure 300 and the trench structure 200, or they may be fitted together. This can be determined based on the material of the magnetic core structure 306 within the magnetic core composite structure 300. If the magnetic core structure 306 is a conductive material, a gap is reserved between the magnetic core composite structure 300 and the trench structure 200; if the magnetic core structure 306 is a non-conductive material, the magnetic core composite structure 300 and the trench structure 200 are fitted together.

[0072] As described above, the method for fabricating an on-chip spiral core inductor provided by the present invention involves separately fabricating a trench structure 200 on a first substrate 201, then separately fabricating a magnetic core composite structure 300 that is incompatible with CMOS processes, and finally using packaging technology to align and electrically interconnect the trench structure 200 and the magnetic core composite structure 300 on the first substrate. This avoids the incompatibility issues caused by the magnetic material process in the magnetic core composite structure 200. This not only solves the current problem of incompatibility between the manufacturing of inductors containing magnetic cores and CMOS processes in integrated circuit production, but also enables mass production of on-chip spiral core inductors, improving device performance.

[0073] Based on the above embodiments, another embodiment of the present invention provides an on-chip spiral core inductor prepared by the fabrication method described in the above embodiments, such as... Figures 15-17 As shown, Figure 16 This is a three-dimensional structural diagram of an on-chip spiral core inductor provided in an embodiment of the present invention. Figure 17 This is a top view of an on-chip spiral core inductor provided in an embodiment of the present invention. The on-chip spiral core inductor includes:

[0074] The trench structure 200 for electrical interconnection and the composite structure of the magnetic core 300;

[0075] The trench structure 200 includes: a first substrate 201 having opposing first and second surfaces; a patterned barrier layer 202 disposed on the first surface; a trench 204 formed in the first surface based on the patterned barrier layer 202; a first metal layer 205 formed on the bottom, sides, and part of the surface of the barrier layer 202 of the trench 204; and contact points 206 formed on the surfaces of the first metal layer 205 on both sides of the trench 204.

[0076] The magnetic core composite structure 300 includes: a second metal layer 303 and a magnetic core structure 306 disposed on the surface of the second metal layer 303.

[0077] As described above, the on-chip spiral core inductor provided by this invention involves separately fabricating a trench structure 200 on a first substrate, then separately fabricating a magnetic core composite structure 300 that is incompatible with CMOS processes, and finally using packaging technology to align and electrically interconnect the trench structure 200 and the magnetic core composite structure 300 on the first substrate 201. This avoids the incompatibility issues caused by the magnetic material processing in the magnetic core composite structure 200. This not only solves the process compatibility problem but also enables mass production of on-chip spiral core inductors, improving device performance.

[0078] Based on the above embodiments, another embodiment of the present invention provides a method for mass production of on-chip spiral core inductors, such as... Figure 18 and Figure 19 As shown, Figure 18 and Figure 19 This is a schematic diagram illustrating the principle of a mass production method for an on-chip spiral core inductor provided in an embodiment of the present invention. The mass production method includes:

[0079] Step S41: Prepare multiple trench structures 200 and multiple magnetic core composite structures 300 using the fabrication method described in the above embodiments;

[0080] Step S42: Electrically interconnect the multiple magnetic core composite structures 300 and the multiple trench structures 200 to form multiple on-chip spiral magnetic core inductors.

[0081] First, such as Figure 18 As shown, multiple magnetic core composite structures 300 can be prepared by the above manufacturing method. The multiple magnetic core composite structures 300 are connected together with polyimide 501 at a certain interval to form a carrier tape.

[0082] Then, as Figure 19As shown, a trench structure 200 is prepared on the first substrate 201 by the above-described fabrication method, and multiple first substrates 201 with trench structures 200 are arranged on the conveyor belt 601 according to the spacing of the magnetic core composite structure 300 on the carrier belt.

[0083] Finally, as Figure 19 As shown, after the trench structure 200 on the first substrate 201 is aligned with the magnetic core composite structure 300 on the carrier tape, pressure is applied and heated using a hot press head 603 to achieve electrical interconnection between the two structures. After the electrical interconnection between the two structures is completed, they are cut, and then the conveyor belt 601 moves to perform the same process on the next pair of structures, and so on, to form multiple on-chip spiral magnetic core inductors, thereby achieving mass production.

[0084] The magnetic core composite structure 300 and the groove structure 200 can be interconnected by hot-press welding or by laser welding.

[0085] As described above, the mass production method for on-chip spiral core inductors provided by this invention involves separately fabricating trench structures on a first substrate, then separately fabricating a magnetic core composite structure incompatible with CMOS processes, and finally using packaging technology to align and electrically interconnect multiple trench structures on the first substrate and multiple magnetic core composite structures to form multiple on-chip spiral core inductors. This not only solves the process compatibility problem but also enables mass production of on-chip spiral core inductors, improving device performance.

[0086] The various embodiments in this specification are described in a progressive, parallel, or combined manner. Each embodiment focuses on its differences from other embodiments, and similar or identical parts between embodiments can be referred to interchangeably. Regarding the on-chip spiral core inductor and its mass production method disclosed in the embodiments, since it corresponds to the fabrication method of the on-chip spiral core inductor disclosed in the embodiments, the description is relatively simple, and relevant parts can be referred to the section on the fabrication method of the on-chip spiral core inductor.

[0087] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that an article or apparatus comprising a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such an article or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the article or apparatus that includes the aforementioned element.

[0088] The above description of the disclosed embodiments enables those skilled in the art to make or use this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for fabricating an on-chip spiral core inductor, characterized in that, The manufacturing method includes: A trench structure is formed on the first substrate; Forming a magnetic core composite structure; The trench structure and the magnetic core composite structure are electrically interconnected; The methods for forming the trench structure include: The first substrate is provided, the first substrate having opposing first and second surfaces; A patterned barrier layer is formed on the first surface; Based on the patterned barrier layer, a trench is formed within the first surface; A first metal layer is formed at the bottom of the trench, on the sides, and on a portion of the surface of the barrier layer; Contact points are formed on the surfaces of the first metal layer on both sides of the trench; The magnetic core composite structure includes: a second metal layer and a magnetic core structure disposed on the surface of the second metal layer. The magnetic core structure is a single-layer thin film of magnetic material layer or a multi-layer composite thin film of magnetic material layer and isolation layer alternating layers. The first metal layer and the second metal layer are electrically interconnected to form the on-chip spiral magnetic core inductor.

2. The manufacturing method according to claim 1, characterized in that, Methods for forming magnetic core composite structures include: A second substrate is provided, the second substrate having a third surface; A sacrificial layer is formed on the third surface; A second metal layer is formed on the sacrificial layer away from the third surface; A magnetic core structure is formed on the second metal layer away from the surface of the sacrificial layer; The sacrificial layer is etched to separate the magnetic core structure and the second metal layer from the second substrate, forming a magnetic core composite structure including the magnetic core structure and the second metal layer.

3. The manufacturing method according to claim 1, characterized in that, The magnetic material layer is any one of a soft magnetic layer, a hard magnetic alloy layer, and an amorphous metal single-layer thin film. The isolation layer is any one of SiO2 layer, Al2O3 layer, HfO2 layer and TiO2 layer.

4. The manufacturing method according to claim 1, characterized in that, The groove structure and the magnetic core composite structure are interconnected by hot-press welding; Alternatively, the trench structure and the magnetic core composite structure may be interconnected by laser welding; Alternatively, the trench structure and the magnetic core composite structure may be interconnected by bonding with conductive adhesive.

5. The manufacturing method according to claim 1, characterized in that, The magnetic core composite structure is shaped to match the trench structure so that the magnetic core composite structure is accommodated within the trench structure.

6. An on-chip spiral core inductor prepared by the manufacturing method according to any one of claims 1-5, characterized in that, The on-chip spiral core inductor includes: Trench structure and magnetic core composite structure for electrical interconnection; The trench structure includes: a first substrate having opposing first and second surfaces; a patterned barrier layer disposed on the first surface; a trench formed in the first surface based on the patterned barrier layer; a first metal layer formed at the bottom, sides, and part of the surface of the barrier layer of the trench; and contact points formed on the surfaces of the first metal layer on both sides of the trench. The magnetic core composite structure includes: a second metal layer and a magnetic core structure disposed on the surface of the second metal layer; the first metal layer and the second metal layer are electrically interconnected to form the on-chip spiral magnetic core inductor.

7. A method for mass production of on-chip spiral core inductors, characterized in that, The mass production method includes: Multiple trench structures and multiple magnetic core composite structures are prepared by the fabrication method described in claim 1; Multiple magnetic core composite structures and multiple trench structures are electrically interconnected to form multiple on-chip spiral magnetic core inductors.

8. The mass production method according to claim 7, characterized in that, The magnetic core composite structure and the groove structure are interconnected by hot-press welding or by laser welding.

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