Magnetic inductor with multiple magnetic layer thicknesses

Information

  • Patent Grant
  • 10593449
  • Patent Number
    10,593,449
  • Date Filed
    Thursday, March 30, 2017
    7 years ago
  • Date Issued
    Tuesday, March 17, 2020
    4 years ago
Abstract
Embodiments are directed to a method of forming a laminated magnetic inductor and resulting structures having multiple magnetic layer thicknesses. A first magnetic stack having one or more magnetic layers alternating with one or more insulating layers is formed in a first inner region of the laminated magnetic inductor. A second magnetic stack is formed opposite a major surface of the first magnetic stack in an outer region of the laminated magnetic inductor. A third magnetic stack is formed opposite a major surface of the second magnetic stack in a second inner region of the laminated magnetic inductor. The magnetic layers are formed such that a thickness of a magnetic layer in each of the first and third magnetic stacks is less than a thickness of a magnetic layer in the second magnetic stack.
Description
BACKGROUND

The present invention generally relates to fabrication methods and resulting structures for semiconductor devices. More specifically, the present invention relates to a laminated magnetic inductor having multiple magnetic layer thicknesses.


Inductors, resistors, and capacitors are the main passive elements constituting an electronic circuit. Inductors are used in circuits for a variety of purposes, such as in noise reduction, inductor-capacitor (LC) resonance calculators, and power supply circuitry. Inductors can be classified as one of various types, such as a winding-type inductor or a laminated film-type inductor. Winding-type inductors are manufactured by winding a coil around, or printing a coil on, a ferrite core. Laminated film-type inductors are manufactured by stacking alternating magnetic or dielectric materials to form laminated stacks.


Among the various types of inductors the laminated film-type inductor is widely used in power supply circuits requiring miniaturization and high current due to the reduced size and improved inductance per coil turn of these inductors relative to other inductor types. A general laminated inductor includes one or more magnetic or dielectric layers laminated with conductive patterns. The conductive patterns are sequentially connected by a conductive via formed in each of the layers and overlapped in a laminated direction to form a spiral-structured coil. Typically, both ends of the coil are drawn out to an outer surface of a laminated body for connection to external terminals.


SUMMARY

Embodiments of the present invention are directed to a method for fabricating a laminated magnetic inductor. A non-limiting example of the method includes forming a first magnetic stack having one or more magnetic layers alternating with one or more insulating layers in a first inner region of the laminated magnetic inductor. A second magnetic stack is formed opposite a major surface of the first magnetic stack in an outer region of the laminated magnetic inductor. A third magnetic stack is formed opposite a major surface of the second magnetic stack in a second inner region of the laminated magnetic inductor. The magnetic layers are formed such that a thickness of a magnetic layer in each of the first and third magnetic stacks is less than a thickness of a magnetic layer in the second magnetic stack.


Embodiments of the present invention are directed to a laminated magnetic inductor. A non-limiting example of the laminated magnetic inductor includes a first inner region having one or more magnetic layers alternating with one or more insulating layers. An outer region having one or more magnetic layers alternating with one or more insulating layers is formed opposite a major surface of the first inner region. A second inner region having one or more magnetic layers alternating with one or more insulating layers is formed opposite a major surface of the outer region. The magnetic layers are formed such that a thickness of a magnetic layer in each of the first and second inner regions is less than a thickness of a magnetic layer in the outer region.


Embodiments of the present invention are directed to a laminated magnetic inductor. A non-limiting example of the laminated magnetic inductor includes a substrate and a first dielectric layer formed opposite a major surface of the substrate. A laminated stack is formed opposite a major surface of the first dielectric layer. The laminated stack includes an inner region adjacent to the first dielectric layer and an outer region formed opposite a major surface of the inner region. A second dielectric layer is formed opposite a major surface of the laminated stack. A conductive coil helically wraps through the first and second dielectric layers. The magnetic layers are formed such that a thickness of a magnetic layer in the inner region is less than a thickness of a magnetic layer in the outer region.


Additional technical features and benefits are realized through the techniques of the present invention. Embodiments and aspects of the invention are described in detail herein and are considered a part of the claimed subject matter. For a better understanding, refer to the detailed description and to the drawings.





BRIEF DESCRIPTION OF THE DRAWINGS

The specifics of the exclusive rights described herein are particularly pointed out and distinctly claimed in the claims at the conclusion of the specification.


The foregoing and other features and advantages of the embodiments of the invention are apparent from the following detailed description taken in conjunction with the accompanying drawings in which:



FIG. 1 depicts a laminated magnetic inductor after a fabrication operation according to embodiments of the invention;



FIG. 2 depicts a laminated magnetic inductor after a fabrication operation according to embodiments of the invention;



FIG. 3 depicts a laminated magnetic inductor after a fabrication operation according to embodiments of the invention;



FIG. 4 depicts a laminated magnetic inductor after a fabrication operation according to embodiments of the invention;



FIG. 5 depicts a laminated magnetic inductor after a fabrication operation according to embodiments of the invention;



FIG. 6 depicts a laminated magnetic inductor after a fabrication operation according to embodiments of the invention;



FIG. 7 depicts a laminated magnetic inductor after a fabrication operation according to embodiments of the invention; and



FIG. 8 depicts a flow diagram illustrating a method according to one or more embodiments of the invention.





The diagrams depicted herein are illustrative. There can be many variations to the diagram or the operations described therein without departing from the spirit of the invention. For instance, the actions can be performed in a differing order or actions can be added, deleted or modified.


In the accompanying figures and following detailed description of the disclosed embodiments, the various elements illustrated in the figures are provided with two or three digit reference numbers. With minor exceptions, the leftmost digit(s) of each reference number correspond to the figure in which its element is first illustrated.


DETAILED DESCRIPTION

For the sake of brevity, conventional techniques related to semiconductor device and integrated circuit (IC) fabrication may or may not be described in detail herein. Moreover, the various tasks and process steps described herein can be incorporated into a more comprehensive procedure or process having additional steps or functionality not described in detail herein. In particular, various steps in the manufacture of laminated inductor devices are well known and so, in the interest of brevity, many conventional steps will only be mentioned briefly herein or will be omitted entirely without providing the well-known process details.


Turning now to an overview of technologies that are more specifically relevant to aspects of the invention, as previously noted herein, laminated film-type inductors offer reduced size and improved inductance per coil turn relative to other inductor types. For this reason, laminated film-type inductors are widely used in applications requiring miniaturization and high current, such as power supply circuitry. The integration of inductive power converters onto silicon is one path to reducing the cost, weight, and size of electronic devices.


Laminated film-type inductor performance can be improved by adding layers of magnetic film. There are two basic laminated film-type magnetic inductor configurations: the closed yoke type laminated inductor and the solenoid type laminated inductor. The closed yoke type laminated inductor includes a metal core (typically a copper wire) and magnetic material wrapped around the core. Conversely, the solenoid type laminated inductor includes a magnetic material core and a conductive wire (e.g., copper wire) wrapped around the magnetic material. Both the closed yoke type laminated inductor and the solenoid type laminated inductor benefit by having very thick magnetic stacks or yokes (e.g., magnetic layers having a thickness of greater than about 200 nm). Thick magnetic layers offer faster throughput and are significantly more efficient to deposit. There are challenges, however, in providing laminated film-type inductor architectures having thick magnetic layers.


One such challenge is addressing the increased loss in energy due to the powerful eddy currents associated with inductors having thick magnetic films. Eddy currents (also known as Foucault currents) are loops of electrical current induced by a changing magnetic field in a conductor. Eddy currents flow in closed loops within conductors in a plane perpendicular to the magnetic field. Eddy currents are created when the time varying magnetic fields in the magnetic layers create an electric field that drives a circular current flow. These losses can be substantial and increase with the thickness of the magnetic layers. As magnetic film thicknesses increase, the eddy currents become severe enough to degrade the quality factor (also known as “Q”) of the inductor. The quality factor of an inductor is the ratio of its inductive reactance to its resistance at a given frequency, and is a measure of its efficiency. The maximum attainable quality factor for a given inductor across all frequencies is known as peak Q (or maximum Q). Some applications can require the peak Q to be at a low frequency and other applications can require the peak Q to be at a high frequency.


The magnetic loss caused by eddy currents in a thick film inductor is largest in the region of the inductor where the coil is in close proximity to the magnetic material. Specifically, magnetic layers closer to the coil (that is, the “inner layers”) have larger losses than magnetic layers further from the coil (the “outer layers”). Moreover, magnetic flux densities in the space occupied by inner layers are generally higher than those characterizing the outer layers due to the magnetic reluctance of the insulating layers (also called spacer layers) interposed between the winding and the outer layers. Due to these relatively large magnetic flux densities in the space occupied by the inner layers, the inner layers tend to magnetically saturate at lower drive currents and have greater losses than the outer layers. Accordingly, the inner layer region is a critical region—the losses in this critical region dominate the overall losses of the inductor. Consequently, if losses can be mitigated or controlled in this critical region the overall performance (i.e., quality factor) of the inductor can be improved.


Turning now to an overview of the aspects of the invention, one or more embodiments of the invention address the above-described shortcomings by providing methods of fabricating a laminated magnetic inductor having multiple magnetic layer thicknesses. A laminated stack having a first inner region, an outer region, and a second inner region is formed opposite a major surface of a substrate. Magnetic layers in the first and second inner regions of the laminated stack are closer (more proximate to) a coil, whereas magnetic layers in the outer region are relatively distant from a coil. The laminated stack is structured such that magnetic layers in the first and second inner regions are thin (e.g., having a thickness of less than about 100 nm), while magnetic layers in the outer region are thick (e.g., having a thickness of greater than about 200 nm). In this manner, eddy current losses can be controlled in critical regions (i.e., the first and second inner regions) while providing improved throughput in noncritical regions (i.e., the outer region). Varying the thicknesses of the magnetic layers in this way advantageously provides a more uniform magnetic flux density while also improving the quality factor of the laminated magnetic inductor.


Turning now to a more detailed description of aspects of the present invention, FIG. 1 depicts a cross-sectional view of a structure 100 having a dielectric layer 102 formed opposite a major surface of a substrate 104 during an intermediate operation of a method of fabricating a semiconductor device according to embodiments of the invention. The dielectric layer 102 can be any suitable material, such as, for example, a low-k dielectric, silicon dioxide (SiO2), silicon oxynitride (SiON), and silicon oxycarbonitride (SiOCN). Any known manner of forming the dielectric layer 102 can be utilized. In some embodiments, the dielectric layer 102 is SiO2 conformally formed on exposed surfaces of the substrate 104 using a conformal deposition process such as PVD, CVD, plasma-enhanced CVD (PECVD), or a combination thereof. In some embodiments, the dielectric layer 102 is conformally formed to a thickness of about 50 nm to about 400 nm, although other thicknesses are within the contemplated scope of embodiments of the invention.


The substrate 104 can be a wafer and can have undergone known semiconductor front end of line processing (FEOL), middle of the line processing (MOL), and back end of the line processing (BEOL). FEOL processes can include, for example, wafer preparation, isolation, well formation, gate patterning, spacer, extension and source/drain implantation, and silicide formation. The MOL can include, for example, gate contact formation, which can be an increasingly challenging part of the whole fabrication flow, particularly for lithography patterning. In the BEOL, interconnects can be fabricated with, for example, a dual damascene process using plasma-enhanced CVD (PECVD) deposited interlayer dielectric (ILDs), PVD metal barriers, and electrochemically plated conductive wire materials. The substrate 104 can include a bulk silicon substrate or a silicon on insulator (SOI) wafer. The substrate 104 can be made of any suitable material, such as, for example, Ge, SiGe, GaAs, InP, AlGaAs, or InGaAs.


A conductive coil 106 is helically wound through the dielectric layer 102. For ease of discussion reference is made to operations performed on and to a conductive coil 106 having six turns or windings formed in the dielectric layer 102 (e.g., the conductive coil 106 wraps around the dielectric layer 102 and other portions of the structure 100 a total of six times). It is understood, however, that the dielectric layer 102 can include any number of windings. For example, the dielectric layer 102 can include a single winding, 2 windings, 5 windings, 10 windings, or 20 windings, although other winding counts are within the contemplated scope of embodiments of the invention. The conductive coil 106 can be made of any suitable conducting material, such as, for example, metal (e.g., tungsten, titanium, tantalum, ruthenium, zirconium, cobalt, copper, aluminum, lead, platinum, tin, silver, gold), conducting metallic compound material (e.g., tantalum nitride, titanium nitride, tantalum carbide, titanium carbide, titanium aluminum carbide, tungsten silicide, tungsten nitride, ruthenium oxide, cobalt silicide, nickel silicide), carbon nanotube, conductive carbon, graphene, or any suitable combination of these materials.



FIG. 2 depicts a cross-sectional view of the structure 100 after forming a first inner layer region 200 opposite a major surface of the dielectric layer 102 during an intermediate operation of a method of fabricating a semiconductor device according to embodiments of the invention. The first inner layer region 200 includes one or more inner magnetic layers (e.g., inner magnetic layer 202) alternating with one or more insulating layers (e.g., insulating layer 204). The first inner layer region 200 is formed by depositing alternating magnetic and insulating layers. For ease of discussion the first inner layer region 200 is depicted as having three inner magnetic layers alternating with three insulating layers. It is understood, however, that the first inner layer region 200 can include any number of inner magnetic layers alternating with a corresponding number of insulating layers. For example, the first inner layer region 200 can include a single inner magnetic layer, two inner magnetic layers, five inner magnetic layers, eight inner magnetic layers, or any number of inner magnetic layers, along with a corresponding number of insulating layers (i.e., as appropriate to form an inner layer region having a topmost insulating layer on a topmost inner magnetic layer and an insulating layer between each pair of adjacent inner magnetic layers).


The inner magnetic layer 202 can be made of any suitable magnetic material known in the art, such as, for example, a ferromagnetic material, soft magnetic material, iron alloy, nickel alloy, cobalt alloy, ferrites, plated materials such as permalloy, or any suitable combination of these materials. In some embodiments, the inner magnetic layer 202 includes a Co containing magnetic material, FeTaN, FeNi, FeAlO, or combinations thereof. Any known manner of forming the inner magnetic layer 202 can be utilized. The inner magnetic layer 202 can be deposited through vacuum deposition technologies (i.e., sputtering) or electrodepositing through an aqueous solution. In some embodiments, the inner magnetic layer 202 is conformally formed on exposed surfaces of the dielectric layer 102 using a conformal deposition process such as PVD, CVD, PECVD, or a combination thereof. Only thin magnetic layers (i.e., layers having a thickness of less than about 100 nm) are formed in the first inner layer region 200. In this manner, losses in the first inner layer region 200 are well-controlled. In some embodiments, the inner magnetic layer 202 is conformally formed to a thickness of about 5 nm to about 100 nm, although other thicknesses are within the contemplated scope of embodiments of the invention.


The insulating layer 204 serves to isolate the adjacent magnetic material layers from each other in the stack and can be made of any suitable non-magnetic insulating material known in the art, such as, for example, aluminum oxides (e.g., alumina), silicon oxides (e.g., SiO2), silicon nitrides, silicon oxynitrides (SiOxNy), polymers, magnesium oxide (MgO), or any suitable combination of these materials. Any known manner of forming the insulating layer 204 can be utilized. In some embodiments, the insulating layer 204 is conformally formed on exposed surfaces of the inner magnetic layer 202 using a conformal deposition process such as PVD, CVD, PECVD, or a combination thereof. The insulating layer 204 can be about one half or greater of the thickness of the inner magnetic layer 202. In some embodiments, the insulating layer 204 is conformally formed to a thickness of about 5 nm to about 10 nm, although other thicknesses are within the contemplated scope of embodiments of the invention.



FIG. 3 depicts a cross-sectional view of the structure 100 after forming an outer layer region 300 opposite a major surface of the first inner layer region 200 during an intermediate operation of a method of fabricating a semiconductor device according to embodiments of the invention. The outer layer region 300 includes one or more outer magnetic layers (e.g., outer magnetic layer 302) alternating with one or more insulating layers (e.g., insulating layer 304). The outer layer region 300 is formed in a similar manner as the first inner layer region 200—by depositing alternating magnetic and insulating layers. For ease of discussion the outer layer region 300 is depicted as having three outer magnetic layers alternating with three insulating layers. It is understood, however, that the outer layer region 300 can include any number of outer magnetic layers alternating with a corresponding number of insulating layers. For example, the outer layer region 300 can include a single outer magnetic layer, two outer magnetic layers, five outer magnetic layers, eight outer magnetic layers, or any number of outer magnetic layers, along with a corresponding number of insulating layers (i.e., as appropriate to form an outer layer region having a topmost insulating layer on a topmost outer magnetic layer and an insulating layer between each pair of adjacent outer magnetic layers). It is further understood that the outer layer region 300 can include a different number of magnetic layers than the first inner layer region 200.


The outer magnetic layer 302 can be made of any suitable magnetic material known in the art, such as, for example, a ferromagnetic material, soft magnetic material, iron alloy, nickel alloy, cobalt alloy, ferrites, plated materials such as permalloy, or any suitable combination of these materials. Any known manner of forming the outer magnetic layer 302 can be utilized. In some embodiments, the outer magnetic layer 302 is conformally formed on exposed surfaces of the first inner layer region 200 using a conformal deposition process such as PVD, CVD, PECVD, or a combination thereof.


As discussed previously herein, the outer layer region 300 is less critical to the overall quality factor of the inductor and thick magnetic layers (i.e., layers having a thickness of more than about 200 nm) can be formed in the outer layer region 300 with only minimal efficiency losses. Consequently, the outer magnetic layer 302 can be conformally formed to a thickness much greater than the inner magnetic layer 202. In some embodiments, the outer magnetic layer 302 is conformally formed to a thickness of about 200 nm to about 800 nm, although other thicknesses are within the contemplated scope of embodiments of the invention. In this manner, throughput of the structure 100 can be improved.


The insulating layer 304 can be made of any suitable non-magnetic insulating material known in the art, such as, for example, aluminum oxides (for example, alumina), silicon oxides, silicon nitrides, polymers, or any suitable combination of these materials. Any known manner of forming the insulating layer 304 can be utilized. In some embodiments, the insulating layer 304 is conformally formed on exposed surfaces of the outer magnetic layer 302 using a conformal deposition process such as PVD, CVD, PECVD, or a combination thereof. In some embodiments, the insulating layer 304 is conformally formed to a thickness of about 5 nm to about 10 nm, although other thicknesses are within the contemplated scope of embodiments of the invention. The insulating layer 304 can have a same thickness, a larger thickness, or a smaller thickness as the insulating layer 204 in the first inner layer region 200.



FIG. 4 depicts a cross-sectional view of the structure 100 after forming a second inner layer region 400 opposite a major surface of the outer layer region 300 during an intermediate operation of a method of fabricating a semiconductor device according to embodiments of the invention. The second inner layer region 400 includes one or more inner magnetic layers (e.g., inner magnetic layer 402) alternating with one or more insulating layers (e.g., insulating layer 404). The second inner layer region 400 is formed in a similar manner as the first inner layer region 200. For ease of discussion the second inner layer region 400 is depicted as having three inner magnetic layers alternating with three insulating layers. It is understood, however, that the second inner layer region 400 can include any number of inner magnetic layers alternating with a corresponding number of insulating layers. For example, the second inner layer region 400 can include a single inner magnetic layer, two inner magnetic layers, five inner magnetic layers, eight inner magnetic layers, or any number of inner magnetic layers, along with a corresponding number of insulating layers (i.e., as appropriate to form an inner layer region having a topmost insulating layer on a topmost inner magnetic layer and an insulating layer between each pair of adjacent inner magnetic layers).


The inner magnetic layer 402 can be made of any suitable magnetic material and can be formed using any suitable process in a similar manner as the inner magnetic layer 202. In some embodiments, the inner magnetic layer 402 is conformally formed to a thickness of about 5 nm to about 100 nm, although other thicknesses are within the contemplated scope of embodiments of the invention. The inner magnetic layer 402 can have a same thickness, a larger thickness, or a smaller thickness as the inner magnetic layer 202 in the first inner layer region 200. Only thin magnetic layers (i.e., layers having a thickness of less than about 100 nm) are formed in the second inner layer region 400. In this manner, losses in the second inner layer region 400 are well-controlled.


The insulating layer 404 can be made of any suitable non-magnetic insulating material and can be formed using any suitable process in a similar manner as the insulating layer 204. In some embodiments, the insulating layer 404 is conformally formed to a thickness of about 5 nm to about 10 nm, although other thicknesses are within the contemplated scope of embodiments of the invention. The insulating layer 404 can have a same thickness, a larger thickness, or a smaller thickness as the insulating layer 204 in the first inner layer region 200.



FIG. 5 depicts a cross-sectional view of the structure 100 after patterning the first inner layer region 200, the outer layer region 300, and the second inner layer region 400 to form laminated stacks 500, 502, and 504 during an intermediate operation of a method of fabricating a semiconductor device according to embodiments of the invention. Any known method for patterning laminated stacks can be used, such as, for example, a wet etch, a dry etch, or a combination of sequential wet and/or dry etches. In some embodiments, the laminated stacks 500, 502, and 504 are formed by removing portions of the first inner layer region 200, the outer layer region 300, and the second inner layer region 400 selective to the dielectric layer 102. For ease of discussion the structure 100 is depicted as having three laminated stacks (e.g., the laminated stacks 500, 502, and 504). It is understood, however, that the structure 100 can include any number of laminated stacks. For example, the structure 100 can include a single laminated stack, two laminated stacks, five laminated stacks, eight laminated stacks, or any number of laminated stacks.



FIG. 6 depicts a cross-sectional view of the structure 100 after forming a dielectric layer 600 opposite a major surface of the dielectric layer 102 during an intermediate operation of a method of fabricating a semiconductor device according to embodiments of the invention. The dielectric layer 600 can be any suitable insulating material, such as, for example, a low-k dielectric, SiO2, SiON, and SiOCN. Any known manner of forming the dielectric layer 600 can be utilized. In some embodiments, the dielectric layer 600 is SiO2 conformally formed opposite a major surface of the dielectric layer 102 using a conformal deposition process such as PVD, CVD, PECVD, or a combination thereof. In some embodiments, the dielectric layer 600 is conformally formed to a thickness sufficient to cover a major surface of the laminated stacks 500, 502, and 504. In some embodiments, a CMP selective to the laminated stacks 500, 502, and 504 planarizes the dielectric layer 600 to a major surface of the laminated stacks 500, 502, and 504.


A dielectric layer 602 is formed opposite a major surface of the dielectric layer 600. The dielectric layer 602 can be any suitable material, such as, for example, a low-k dielectric, SiO2, SiON, and SiOCN. Any known manner of forming the dielectric layer 602 can be utilized. In some embodiments, the dielectric layer 602 is SiO2 conformally formed opposite a major surface of the dielectric layer 600 using a conformal deposition process such as PVD, CVD, PECVD, or a combination thereof. In some embodiments, the dielectric layer 602 is conformally formed to a thickness of about 50 nm to about 400 nm, although other thicknesses are within the contemplated scope of embodiments of the invention.


One or more coils 604 are formed in the dielectric layer 602, in a similar manner as the coils 106 formed in the dielectric layer 102. For ease of discussion reference is made to operations performed on and to a structure 100 having six coils (e.g., the coils 604) formed in the dielectric layer 602. It is understood, however, that the dielectric layer 602 can include any number of coils. For example, the dielectric layer 602 can include a single coil, 2 coils, 5 coils, 10 coils, or 20 coils, although other coil counts are within the contemplated scope of embodiments of the invention. The coils 602 can be made of any suitable conducting material, such as, for example, metal (e.g., tungsten, titanium, tantalum, ruthenium, zirconium, cobalt, copper, aluminum, lead, platinum, tin, silver, gold), conducting metallic compound material (e.g., tantalum nitride, titanium nitride, tantalum carbide, titanium carbide, titanium aluminum carbide, tungsten silicide, tungsten nitride, ruthenium oxide, cobalt silicide, nickel silicide), carbon nanotube, conductive carbon, graphene, or any suitable combination of these materials. The dielectric layer 602 can include the same, more, or less coils than the dielectric layer 102.



FIG. 7 depicts a cross-sectional view of a structure 700 having a first inner layer region 200 and an outer layer region 300 formed during an intermediate operation of a method of fabricating a semiconductor device according to embodiments of the invention. The structure 700 is formed in a similar manner as the structure 100, except that the structure 700 omits the second inner layer region 400 (as depicted in FIG. 6). In some embodiments, the dielectric layer 602 is formed opposite a major surface of a topmost outer magnetic layer 702 of the outer layer region 300.



FIG. 8 depicts a flow diagram illustrating a method according to one or more embodiments of the invention. As shown at block 802, a first magnetic layer is formed in a first inner region of a laminated stack. The first magnetic layer can be formed in a similar manner as the inner magnetic layer 202 (as depicted in FIG. 2) according to one or more embodiments.


As shown at block 804, a second magnetic layer is formed in an outer region of the laminated stack opposite a major surface of the first inner region. The second magnetic layer can be formed in a similar manner as the outer magnetic layer 302 (as depicted in FIG. 3) according to one or more embodiments.


As shown at block 806 a third magnetic layer is formed in a second inner region of the laminated stack opposite a major surface of the outer region. The third magnetic layer can be formed in a similar manner as the inner magnetic layer 402 (as depicted in FIG. 4) according to one or more embodiments.


As discussed previously herein, the laminated stack can be structured such that a thickness of the first and third magnetic layers is less than a thickness of the second magnetic layer. In this manner, eddy current losses can be controlled in critical regions (i.e., the first and second inner regions) while providing improved throughput in noncritical regions (i.e., the outer region).


Various embodiments of the present invention are described herein with reference to the related drawings. Alternative embodiments can be devised without departing from the scope of this invention. Although various connections and positional relationships (e.g., over, below, adjacent, etc.) are set forth between elements in the following description and in the drawings, persons skilled in the art will recognize that many of the positional relationships described herein are orientation-independent when the described functionality is maintained even though the orientation is changed. These connections and/or positional relationships, unless specified otherwise, can be direct or indirect, and the present invention is not intended to be limiting in this respect. Similarly, the term “coupled” and variations thereof describes having a communications path between two elements and does not imply a direct connection between the elements with no intervening elements/connections between them. All of these variations are considered a part of the specification. Accordingly, a coupling of entities can refer to either a direct or an indirect coupling, and a positional relationship between entities can be a direct or indirect positional relationship. As an example of an indirect positional relationship, references in the present description to forming layer “A” over layer “B” include situations in which one or more intermediate layers (e.g., layer “C”) is between layer “A” and layer “B” as long as the relevant characteristics and functionalities of layer “A” and layer “B” are not substantially changed by the intermediate layer(s).


The following definitions and abbreviations are to be used for the interpretation of the claims and the specification. As used herein, the terms “comprises,” “comprising,” “includes,” “including,” “has,” “having,” “contains” or “containing,” or any other variation thereof, are intended to cover a non-exclusive inclusion. For example, a composition, a mixture, process, method, article, or apparatus that comprises a list of elements is not necessarily limited to only those elements but can include other elements not expressly listed or inherent to such composition, mixture, process, method, article, or apparatus.


Additionally, the term “exemplary” is used herein to mean “serving as an example, instance or illustration.” Any embodiment or design described herein as “exemplary” is not necessarily to be construed as preferred or advantageous over other embodiments or designs. The terms “at least one” and “one or more” are understood to include any integer number greater than or equal to one, i.e. one, two, three, four, etc. The terms “a plurality” are understood to include any integer number greater than or equal to two, i.e. two, three, four, five, etc. The term “connection” can include an indirect “connection” and a direct “connection.”


References in the specification to “one embodiment,” “an embodiment,” “an example embodiment,” etc., indicate that the embodiment described can include a particular feature, structure, or characteristic, but every embodiment may or may not include the particular feature, structure, or characteristic. Moreover, such phrases are not necessarily referring to the same embodiment. Further, when a particular feature, structure, or characteristic is described in connection with an embodiment, it is submitted that it is within the knowledge of one skilled in the art to affect such feature, structure, or characteristic in connection with other embodiments whether or not explicitly described.


For purposes of the description hereinafter, the terms “upper,” “lower,” “right,” “left,” “vertical,” “horizontal,” “top,” “bottom,” and derivatives thereof shall relate to the described structures and methods, as oriented in the drawing figures. The terms “overlying,” “atop,” “on top,” “positioned on” or “positioned atop” mean that a first element, such as a first structure, is present on a second element, such as a second structure, wherein intervening elements such as an interface structure can be present between the first element and the second element. The term “direct contact” means that a first element, such as a first structure, and a second element, such as a second structure, are connected without any intermediary conducting, insulating or semiconductor layers at the interface of the two elements.


The terms “about,” “substantially,” “approximately,” and variations thereof, are intended to include the degree of error associated with measurement of the particular quantity based upon the equipment available at the time of filing the application. For example, “about” can include a range of ±8% or 5%, or 2% of a given value.


The phrase “selective to,” such as, for example, “a first element selective to a second element,” means that the first element can be etched and the second element can act as an etch stop.


The term “conformal” (e.g., a conformal layer) means that the thickness of the layer is substantially the same on all surfaces, or that the thickness variation is less than 15% of the nominal thickness of the layer.


The flowchart and block diagrams in the Figures illustrate possible implementations of fabrication and/or operation methods according to various embodiments of the present invention. Various functions/operations of the method are represented in the flow diagram by blocks. In some alternative implementations, the functions noted in the blocks can occur out of the order noted in the Figures. For example, two blocks shown in succession can, in fact, be executed substantially concurrently, or the blocks can sometimes be executed in the reverse order, depending upon the functionality involved.


The descriptions of the various embodiments of the present invention have been presented for purposes of illustration, but are not intended to be exhaustive or limited to the embodiments disclosed. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the described embodiments. The terminology used herein was chosen to best explain the principles of the embodiments, the practical application or technical improvement over technologies found in the marketplace, or to enable others of ordinary skill in the art to understand the embodiments described herein.

Claims
  • 1. A laminated magnetic inductor comprising: a substrate;a first dielectric layer formed opposite a major surface of the substrate;a laminated stack formed opposite a major surface of the first dielectric layer, the laminated stack comprising an inner region adjacent to the first dielectric layer and an outer region formed opposite a major surface of the inner region;a second dielectric layer formed opposite a major surface of the laminated stack; anda conductive coil helically wrapping through the first and second dielectric layers;wherein a thickness of a magnetic layer in the inner region is less than a thickness of a magnetic layer in the outer region.
  • 2. The laminated magnetic inductor of claim 1, wherein a thickness of a magnetic layer in the inner region is about 5 nm to about 100 nm.
  • 3. The laminated magnetic inductor of claim 1, wherein a thickness of a magnetic layer in the outer region is about 200 nm to about 800 nm.
US Referenced Citations (103)
Number Name Date Kind
5194806 Obama Mar 1993 A
5576099 Canaperi et al. Nov 1996 A
5756201 Kadono et al. May 1998 A
5774025 Adam et al. Jun 1998 A
6184143 Ohashi et al. Feb 2001 B1
6346336 Nago Feb 2002 B1
6377157 Liu et al. Apr 2002 B1
6504466 Katsurada Jan 2003 B1
6593838 Yue Jul 2003 B2
6613459 Saito et al. Sep 2003 B1
6630255 Litvinov et al. Oct 2003 B1
6731460 Sasaki May 2004 B2
6759297 Dvorsky et al. Jul 2004 B1
6943658 Gardner Sep 2005 B2
6982196 Belyansky et al. Jan 2006 B2
7016170 Nishioka Mar 2006 B2
7202516 Belyansky et al. Apr 2007 B2
7238990 Burnett et al. Jul 2007 B2
7380328 Ahn et al. Jun 2008 B2
7488659 Dyer Feb 2009 B2
7737052 Bhatia et al. Jun 2010 B2
7755124 Fajardo et al. Jul 2010 B2
7791837 Fujiwara Sep 2010 B2
7847668 Lai et al. Dec 2010 B2
7906383 Richter et al. Mar 2011 B2
7936246 Hopper et al. May 2011 B2
7982286 Rossi et al. Jul 2011 B2
8044755 Smeys et al. Oct 2011 B2
8049993 Shirotori et al. Nov 2011 B2
8093981 Chung Jan 2012 B2
8278164 Li et al. Oct 2012 B2
8299615 Fayaz et al. Oct 2012 B2
8308964 Xu et al. Nov 2012 B2
8314676 Smeys et al. Nov 2012 B1
8323728 Iorio et al. Dec 2012 B2
8354694 Bedell et al. Jan 2013 B2
8466537 Papou et al. Jun 2013 B1
8587400 Nakajima et al. Nov 2013 B2
8691696 Cai et al. Apr 2014 B2
8698328 Nair et al. Apr 2014 B2
8704627 Kuroda Apr 2014 B2
8717136 Fontana, Jr. et al. May 2014 B2
8736413 Yokoyama et al. May 2014 B2
8749338 Takahashi Jun 2014 B2
8823482 Singh et al. Sep 2014 B2
9047890 Herget Jun 2015 B1
9129817 Elsherbini et al. Sep 2015 B2
9153547 Crawford et al. Oct 2015 B2
9231072 Alptekin Jan 2016 B2
9324495 Fontana, Jr. et al. Apr 2016 B2
9356121 Jagannathan May 2016 B2
9412866 Kuoh et al. Aug 2016 B2
9437668 Deligianni et al. Sep 2016 B1
9697948 Osada et al. Jul 2017 B2
9799519 Joseph Oct 2017 B1
10236209 Sharan et al. Mar 2019 B2
20010050607 Gardner Dec 2001 A1
20030077871 Cheng et al. Apr 2003 A1
20040046631 Sakakura et al. Mar 2004 A1
20040219328 Tasaki et al. Nov 2004 A1
20060222821 Masai Oct 2006 A1
20070030659 Suzuki et al. Feb 2007 A1
20070285835 Sun et al. Dec 2007 A1
20080036536 Khorramabadi Feb 2008 A1
20080284552 Lim et al. Nov 2008 A1
20110050607 Park Mar 2011 A1
20110133880 Pitts et al. Jun 2011 A1
20110172111 Cantor et al. Jul 2011 A1
20120233849 Smeys et al. Sep 2012 A1
20120236528 Le et al. Sep 2012 A1
20120267733 Hu et al. Oct 2012 A1
20120319236 Chen et al. Dec 2012 A1
20130056847 Chen Mar 2013 A1
20130106552 Fontana, Jr. et al. May 2013 A1
20130224887 Lee et al. Aug 2013 A1
20140027880 Duevel et al. Jan 2014 A1
20140062646 Morrissey Mar 2014 A1
20140068932 Sturcken Mar 2014 A1
20140216939 Fontana, Jr. et al. Aug 2014 A1
20140349414 Zhong et al. Nov 2014 A1
20150109088 Kim et al. Apr 2015 A1
20150115404 Hsueh et al. Apr 2015 A1
20150137931 Mano et al. May 2015 A1
20150171157 Sturcken et al. Jun 2015 A1
20150187772 Choi et al. Jul 2015 A1
20150338474 Mohan et al. Nov 2015 A1
20150340149 Lee et al. Nov 2015 A1
20160086960 Wen et al. Mar 2016 A1
20160260708 Herget et al. Sep 2016 A1
20180197670 Deligianni et al. Jan 2017 A1
20170179154 Furihata Jun 2017 A1
20170250134 Sturcken et al. Aug 2017 A1
20180005741 Doris et al. Jan 2018 A1
20180286581 Deligianni et al. Oct 2018 A1
20180286582 Deligianni et al. Oct 2018 A1
20180294094 Deligianni et al. Oct 2018 A1
20180308612 Park et al. Oct 2018 A1
20180308920 Deligianni et al. Oct 2018 A1
20180308921 Deligianni et al. Oct 2018 A1
20180323158 Deligianni et al. Nov 2018 A1
20180336991 Deligianni et al. Nov 2018 A1
20190006083 Deligianni et al. Jan 2019 A1
20190157000 Deligianni et al. May 2019 A1
Foreign Referenced Citations (1)
Number Date Country
102529211 Jul 2012 CN
Non-Patent Literature Citations (22)
Entry
Deligianni et al., “Stress Management for Thick Magnetic Film Inductors,” U.S. Appl. No. 15/599,754, filed May 19, 2017.
Deligianni et al., “Stress Management for Thick Magnetic Film Inductors,” U.S. Appl. No. 16/107,102, filed Aug. 21, 2018.
Deligianni et al., “Magnetic Inductor Stacks,” U.S. Appl. No. 15/403,292, filed Jan. 11, 2017.
Deligianni et al., “Magnetic Inductor Stacks,” U.S. Appl. No. 15/800,702, filed Nov. 1, 2017.
List of IBM Patents or Patent Applications Treated as Related; (Appendix P), Date Filed Oct. 10, 2018; 2 pages.
Deligianni et al.; “Laminated Magnetic Inductor Stack With High Frequency Peak Quality Factor”; U.S. Appl. No. 15/479,615, filed Apr. 5, 2017.
Deligianni et al.; “Magnetic Inductor Stack Including Insulating Material Having Multiple Thicknesses”; U.S. Appl. No. 15/584,766, filed May 2, 2017.
Deligianni et al.; “Magnetic Inductor Stack Including Magnetic Materials Having Multiple Permeabilities”; U.S. Appl. No. 15/494,871, filed Apr. 24, 2017.
Deligianni et al.; “Magnetic Inductor With Shape Anisotrophy”; U.S. Appl. No. 15/476,147, filed Mar. 31, 2017.
List of IBM Patents or Patent Applications Treated as Related; Date Filed: Jan. 15, 2018, 2 pages.
Deligianni et al.; “Magnetic Inductor Stack Including Magnetic Materials Having Multiple Permeabilities”; U.S. Appl. No. 15/966,202, filed Apr. 30, 2018.
List of IBM Patents or Patent Applications Treated as Related; Date Filed: Apr. 30, 2018, 2 pages.
E. Quandt et al., “Magnetostrictive LC circuit sensors,” Materials Transactions, vol. 45, No. 2, 2004, pp. 244-248.
Gao, “Significantly Enhanced Inductance and Quality Factor of GHz Integrated Magnetic Solenoid Inductors With FeGaB/A12O3 Multilayer Films”, IEEE Transactions on Electron Devices, vol. 61, No. 5, May 2014, pp. 1470-1476, IEEE.
Iakubov et al., “Control over magnetic spectrum of multilayer magnetic film metamaterial,” AIP Advances, vol. 5, No. 7, 2015, 077116, 7 pages.
Deligianni et al., “Magnetic Inductor With Multiple Magnetic Layer Thicknesses”, U.S. Appl. No. 16/236,795, filed Dec. 31, 2018.
List of IBM Patents or Patent Applications Treated as Related; (Appendix P), Date Filed Jan. 23, 2019; 2 pages.
Deligianni et al., “Laminated Magnetic Inductor Stack With High Frequency Peak Quality Factor,” U.S. Appl. No. 16/591,964, filed Oct. 3, 2019.
Deligianni et al., “Magnetic Inductor With Shape Anisotrophy,” U.S. Appl. No. 16/591,954, filed Oct. 3, 2019.
List of IBM Patents or Patent Applications Treated As Related; (Appendix P), Date filed Oct. 4, 2019; 2 pages.
Deligianni et al., “Stress Management for Thick Magnetic Film Inductors,” U.S. Appl. No. 16/391,383, filed Apr. 23, 2019.
List of IBM Patents or Patent Applications Treated As Related; (Appendix P), Date filed Sep. 13, 2019; 2 pages.
Related Publications (1)
Number Date Country
20180286581 A1 Oct 2018 US