Patent Description:
There are many different techniques which are currently being used to fabricate power supplies. Emerging solutions include power supply-in-package (PSiP) and power supply-on-chip (PwrSoC). One such technique is integrated voltage regulator (IVR) technology. IVR technology involves the integration of the power supply with the load either monolithically, in <NUM>. 5D/3D, in package or in substrate. IVRs improve the efficiency of power delivery, through elimination of parasitics and a faster transient response. Through miniaturization and integration of magnetic components, the technology removes the need for discrete and bulky magnetics, thereby dramatically reducing the form-factor and footprint of the power conversion circuitry. IVRs also provide the further advantage of a reduced requirement for decoupling capacitors. In addition, IVRs can provide power supply granularity, which can result in a significant increase in power system efficiency.

The major roadblock in realizing an ever increasing number of small integrated dc-dc switching regulators needed in microelectronics applications is due to the size (profile and footprint) of the magnetic passive components. Typically, the micro-fabricated magnetic passive components use four different types of planar structures, namely stripline, spiral, toroid and solenoid. These planar structures are typically fabricated using thin-film processing of magnetic cores and conductor windings.

<CIT> and <CIT> disclose replacement of the via conductor by a coaxial arrangement of an inner column and an outer column with intermediate isolator. <CIT> describes a magnetic layer that surrounds the entire via conductor.

It is an object of the present invention to provide an inductor structure which overcomes at least one of the above mentioned problems.

According to one aspect of the invention there is provided a transformer or a coupled inductor device, as set out in the appended claims.

The invention will be more clearly understood from the following description of an embodiment thereof, given by way of example only, with reference to the accompanying drawings, of which only <FIG>, <FIG> and <FIG> show embodiments of the present invention.

An embodiment of an inductor device that does not form part of the invention is shown in <FIG>. In this embodiment, the inductor device <NUM> comprises three columns <NUM> of conductive material embedded in a supporting structure <NUM>, with a magnetic layer in the form of a magnetic core <NUM> surrounding each column <NUM>. The columns comprise an input column <NUM>, an output column <NUM>, and an intermediate column <NUM>. An input/output pad <NUM> is connected to the input column to form the input terminal of the inductor and an input/output pad <NUM> is connected to the output column to form the output terminal of the inductor. The columns are alternately interconnected at their ends by means of conductive tracks. In the embodiment shown, a first set of tracks 9a extend along the bottom surface of the supporting structure <NUM> and a second set of tracks 9b extend along the top surface of the supporting structure <NUM>. However, in other embodiments, the tracks can be embedded inside the supporting structure.

In the embodiment of <FIG>, the magnetic core <NUM> comprises alternating layers of magnetic <NUM> and dielectric materials <NUM>, where the core itself has the quality of being either magnetically isotropic or magnetically anisotropic. As is shown in <FIG>, the inductor device has been released from an underlying support substrate.

The magnetic core <NUM> and the columns <NUM> both may be deposited by any suitable means and may also comprise any suitable materials. Some suitable deposition methods are chemical vapour deposition (CVD), physical vapour deposition (PVD) and electrodeposition. Some suitable magnetic materials are CZT, CZTB, FINEMET, CoP, NiFe and CoNiFe. Some suitable dielectric materials are AlN, SiO2, Si3N4, Si2N2O, SiC, Si, SiLK, polyimide, parylene, benzocyclobutene (BCB), polybenzoxazole (PBO), tetraethylorthosilicate (TEOS), fluorinated TEOS (FTEOS), doped glass (BPSG, PSG, BSG), organo-silicate glass (OSG), fluorinated glass (FSG), spin-on glass (SOG) and Al2O3. Some suitable conductive materials are Cu, Al, Ag and Au.

It will be appreciated that any number of columns <NUM> may be embedded in the supporting structure <NUM>, depending on the requirements of the circuitry with which the inductor device is to be used. In embodiments where the inductor device comprises more than three columns, the vertical magnetic structure comprises a single input column to which the input/output pad forming the input terminal is connected at one end, a single output column to which the input/output pad forming the output terminal is connected at one end, and a plurality of intermediate columns. Where the inductor device comprises two columns, the vertical magnetic structure simply comprises an input column and an output column. The input/output pad forming the input terminal is then connected to one end of the input column and the input/output pad forming the output terminal is connected to the same end of the output column. Where the inductor device comprises only one column, the input/ output pads forming the respective input and output terminals are connected to opposite ends of the same column.

As previously mentioned, the columns of conductive material are alternately connected with interconnecting tracks of conductive material. In the embodiment where the inductor device comprises three or more columns, this is achieved by a first end of each intermediate column being conductively coupled to a first end of a first adjacent column and isolated from a first end of a second adjacent column and a second end of each intermediate column being conductively coupled to a second end of a second adjacent column and not coupled to a second end of the first adjacent column. The I/O pad for wire bonding/flip chip is then connected to the end of the input column and the end of the output column that is not connected to an intermediate column.

<FIG> shows another embodiment of the inductor device that does not form part of the present invention. This embodiment comprises the same features as <FIG>, except that it further includes a support substrate <NUM> coupled to the first set of tracks 9a of conductive material. The supporting structure <NUM> of the embodiment of <FIG> comprises a passivation layer. The passivation layer comprises a non-conductive and non-magnetic material. One example of such a material is a photoresist such as SU-<NUM>, or any light-sensitive material used in lithography. The supporting structure and the columns together may comprise a PCB, a functional substrate, a package or an interposer. The supporting structure may comprise any suitable magnetic material, such as ferrite or NiFe.

The first and second interconnecting tracks of conductive material are coated with a magnetic material. This magnetic material may comprise alternating laminations of any suitable magnetic and dielectric materials. This coating can be achieved in a number of different ways. In a first embodiment, the coating of magnetic material completely wraps the tracks, forming a closed core. In a second embodiment, the magnetic material partially coats the tracks such that it is only located beneath the tracks. In a third embodiment, the magnetic material partially coats the tracks such that it is only located over the tracks. In a fourth embodiment, the magnetic material partially coats the tracks such that it is located both beneath and over the tracks.

<FIG> shows the main steps in the fabrication process to obtain the inductor device of <FIG>. In step <NUM>, one or more columns of conductive material are deposited on a support substrate, the one or more columns comprising an input terminal and an output terminal. In step <NUM>, a magnetic layer in the form of a magnetic core is deposited around each column. In step <NUM>, a fill material is deposited around and between each column to provide a supporting structure. In step <NUM>, the columns are selectively interconnected with tracks of conductive material and I/O pads are deposited on the input terminal and the output terminal.

In the case where the inductor device comprises three or more columns comprising an input column, an output column and a plurality of intermediate columns, the selective interconnection of the columns with tracks of conductive material is such that the first end of each intermediate column is conductively coupled to the first end of a first adjacent column and isolated from the first end of a second adjacent column and the second end of each intermediate column is conductively coupled to the second end of the second adjacent column and not coupled to the second end of the first adjacent column. The I/O pad for wire bonding/flip chip is then connected to the end of the input column and the end of the output column that is not connected to an intermediate column.

<FIG> shows a detailed schematic of one fabrication process to obtain the inductor device of <FIG>, where the device comprises an input column, an output column and at least one intermediate column. In the first step of the fabrication process, spaced apart columns of conductive material are deposited on a first support substrate (step <NUM>). In step <NUM>, a first magnetic layer in the form of a magnetic core comprising alternating laminations of magnetic and dielectric materials is conformally deposited on and in between each column. This involves coating all of the exposed surfaces of the columns and the first support substrate with the magnetic core such that the magnetic core is deposited vertically around each column, horizontally on the first support substrate between each column, and horizontally on a first end of each column distal to the first support substrate. In step <NUM>, a fill material is deposited around and in the gaps between each column to provide a supporting structure. In step <NUM>, the surface of the supporting structure is planarized to remove the horizontal magnetic core deposited on the first end of each column. In step <NUM>, the intermediate columns are connected with a first set of conductive tracks such that the first end of each intermediate column is conductively coupled to the first end of a first adjacent column and isolated from the first end of a second adjacent column. I/O pads for wire bonding/flip chip may also be connected at this stage. In step <NUM>, a second support substrate is mounted to the first set of tracks of conductive material and the structure is inverted. In step <NUM>, the first support substrate is removed. In step <NUM>, the surface of a second end of each column is planarized in order to remove the horizontal magnetic core between each column. In step <NUM>, the intermediate columns are connected with a second set of interconnecting conductive tracks such that the second end of each intermediate column is conductively coupled to the second end of the second adjacent column and not coupled to the second end of the first adjacent column. A second I/O pad for wire bonding/flip chip may also be connected at this stage.

<FIG> shows a detailed schematic of another fabrication process to obtain the inductor device of <FIG>, where the device comprises an input column, an output column and at least one intermediate column. In the first step of the fabrication process, a plurality of lengths of a first insulating material are deposited on a support substrate, where a first set of tracks of conductive material are then deposited on those portions of the support substrate which are not in contact with the first insulating material. I/O pads may also be deposited at this stage (step <NUM>). In step <NUM>, further first insulating material is deposited on the plurality of lengths of the first insulating material and also on selective portions of the first set of tracks of conductive material in order to form a plurality of spaced apart columns of the first insulating material. In step <NUM>, columns of conductive material are deposited between the plurality of spaced apart columns of insulating material such that a second end of each intermediate column is conductively coupled to the second end of a first adjacent column by the first set of tracks of conductive material and isolated from the second end of a second adjacent column. In step <NUM>, the first insulating material is removed. In step <NUM>, a thin film of a second insulating material is deposited on both the planar surfaces of the conductive columns and the support substrate. A first magnetic layer in the form of a magnetic core is then deposited around each column. In step <NUM>, a fill material is deposited around and in the gaps between each conductive column to form a supporting structure. In step <NUM>, the second insulating material on a first end of the conductive columns is removed. In step <NUM>, the intermediate columns are connected with a second set of interconnecting conductive tracks such that the first end of each intermediate column is conductively coupled to the first end of the second adjacent column and not coupled to the first end of the first adjacent column. I/O pads for wire bonding/flip chip may also be connected at this stage.

<FIG> shows four additional alternative embodiments of the inductor device that do not form part of the present invention. In the embodiment of <FIG>, each column is embedded in a magnetic layer formed by a magnetic core, which also acts as a supporting structure. The magnetic core comprises a solid sheet of magnetic material.

<FIG> shows a top down and a side view respectively of an alternative embodiment to <FIG>, where the magnetic core comprises a plurality of rings concentric to each column, with a vertically-oriented intervening dielectric in between the rings. <FIG> shows a side view of yet another embodiment, where the magnetic core comprises a plurality of rings concentric to each column of alternating horizontal laminations of magnetic and dielectric materials, with a vertically-oriented intervening dielectric in between the rings.

<FIG> shows an embodiment similar to <FIG>, but where the magnetic core comprises a laminated solid sheet of alternating horizontal laminations of magnetic and dielectric materials.

<FIG> shows a detailed schematic of an embodiment of the fabrication process to obtain the inductor device of the type shown in <FIG>, where the device comprises an input column, an output column and at least one intermediate column. In the first step of the fabrication process, a plurality of spaced apart columns of a first insulating material are deposited on a first support substrate (<NUM>). In step <NUM>, columns of conductive material are then deposited between the plurality of spaced apart columns of the first insulating material. In step <NUM>, the first insulating material is removed. In step <NUM>, a second layer and a third layer of the same insulating material are deposited on the first support substrate. The second layer of insulating material makes contact with the support substrate and extends between the columns of conductive material. The third layer of insulating material is located on a portion of the surface of second layer of insulating material. In step <NUM>, a thin film of a fourth insulating material of a different type to the second and third layers of insulation is deposited on both the planar surfaces of the conductive columns and the second and third insulating layers. In step <NUM>, the second and third layers of insulating material are removed. In step <NUM>, a fifth insulation layer is deposited around the vertical sidewalls of the conductive columns. In step <NUM>, a magnetic layer is deposited in the spaces between the conductive columns so as to form a magnetic core and act as a supporting structure. The thickness of the magnetic core is equal to the thickness of the conductive columns. As previously explained, the magnetic core can be in the form of a solid sheet or take the form of rings which are concentric to each column, with a vertically-oriented dielectric in between the rings. In step <NUM>, the fourth insulating material is removed from the conductive columns. In step <NUM>, a sixth and a seventh layer of insulation is deposited on the surface of the magnetic core distal from the first support substrate. In step <NUM>, a seed layer is deposited on top of the sixth and seventh layers of insulation. In step <NUM>, the columns are connected with a first set of interconnecting conductive tracks such that a first end of each intermediate column is conductively coupled to the first end of a second adjacent column and not coupled to the first end of a first adjacent column. I/O pads for wire bonding/flip chip may also be connected at this stage. In step <NUM>, the surface of the first end of each column is planarized in order to remove the excess material. In step <NUM>, a second support substrate is mounted to the first set of tracks of conductive material and the structure is inverted. In step <NUM>, the first support substrate is removed. In step <NUM>, the columns are connected with a second set of interconnecting conductive tracks such that a second end of each intermediate column is conductively coupled to the second end of the first adjacent column and not coupled to the second end of the second adjacent column. I/O pads for wire bonding/flip chip may also be connected at this stage.

Steps 600a to 630a show an alternative technique which can be performed in place of steps <NUM> to <NUM>. In this technique, a plurality of spaced apart conductive columns are deposited on a first support substrate (600a). In step 605a, a dielectric is deposited on all of the exposed surfaces of the columns and the first support substrate such that the dielectric is deposited vertically around each column, horizontally on the first support substrate between each column, and horizontally on a first end of each column distal to the first support substrate. In step 610a, a second support substrate is mounted to the columns and the structure is inverted. In step 615a, the first support substrate is removed. In step 620a, second and third layers of insulation material are deposited on the first support substrate. In step 625a, a dielectric is deposited on the horizontal surfaces of the columns and the second and third layers of insulation material. In step 630a, the second and third layers of insulation material are removed. The process then continues at step <NUM>, as previously described.

<FIG> shows a detailed schematic of one embodiment of the fabrication process to obtain the inductor device of the type shown in <FIG>, where the device comprises an input column, an output column and at least one intermediate column. In the first step, a magnetic layer in the form of a magnetic core, which is in the form of a planar sheet comprising a plurality of alternating horizontal laminations of magnetic and dielectric materials, is deposited on a first support substrate (<NUM>). In step <NUM>, a selective etch creates discrete columnar voids in the magnetic core. In step <NUM>, a first insulation layer is deposited conformally, covering both the planar and vertical surfaces of the magnetic core. In step <NUM>, a second support substrate is mounted to the magnetic core and the structure is inverted. In step <NUM>, the first support substrate is removed. In step <NUM>, columns of conductive material are deposited into the discrete columnar voids in the magnetic core. The process then continues to step <NUM> of <FIG> until step <NUM> of <FIG>. Then, in step <NUM> the columns are connected with a second set of interconnecting conductive tracks such that a second end of each intermediate column is conductively coupled to the second end of the second adjacent column and not coupled to the second end of the first adjacent column. I/O pads for wire bonding/flip chip may also be connected at this stage.

In the embodiment shown in <FIG>, the magnetic core is in the form or a solid sheet. However, as previously explained in relation to <FIG>, in another embodiment, the magnetic core can take the form of rings which are concentric to each columnar void, with a vertically-oriented dielectric in between the rings.

Figure <NUM> shows a 3D view of the inductor device of <FIG> along with a <NUM>° cross-sectional view of a column of conductive material from that same structure (the supporting structure is not shown for clarity purposes). The column of conductive material is surrounded by a first magnetic layer in the form of a magnetic core, where the magnetic core may comprise laminations of alternating magnetic and dielectric materials.

<FIG> shows a 3D view of an embodiment of the inductor device of the present invention where the structure comprises a coaxial or concentric structure (the supporting structure is not shown for clarity purposes). This concentric structure provides a coupling of <NUM>, as well as a perfect dc flux cancelation in the core. If the Re-Distribution Layer (RDL) top and bottom traces are placed on top of each other, a transformer with ultra-low leakage inductance and excellent coupling is achieved. A <NUM>° cross-sectional view of a concentric column of conductive material from that same structure is also shown in <FIG>, where each concentric column comprises two individual columns of conductive material that are electrically insulated from one another, where each individual column of conductive material is further surrounded by a magnetic layer in the form of a magnetic core. According to the invention, the magnetic core comprises alternating vertical laminations of magnetic and dielectric materials.

<FIG> shows a detailed schematic of the fabrication process of the inductor device shown in <FIG>, where the device comprises an input column, an output column and at least one intermediate column. In the first step of the fabrication process, a first set of conductive columns is deposited on a first support substrate (<NUM>). In step <NUM>, a first magnetic layer in the form of a magnetic core is conformally deposited on both the planar and vertical surfaces of the conductive columns and on the surface of the first support substrate between the columns. In step <NUM>, a layer of conductive material is conformally deposited on top of the first magnetic core, to form a second set of conductive columns concentric to the first set of conductive columns. In step <NUM>, a second magnetic layer in the form of a magnetic core is conformally deposited on top of the second set of conductive columns. In step <NUM>, a fill material is deposited around and in the gaps between the columns to provide a supporting structure. In step <NUM>, the surface of a first end of each column distal to the first support substrate is planarized in order to remove excess material on top of and between each column. In step <NUM>, a first set of interconnecting tracks of conductive material are deposited such that the first end of each intermediate column of the first set of columns is conductively coupled to the first end of a first adjacent column of the first set of columns and isolated from the first end of a second adjacent column of the first set of columns and the first end of each intermediate column of the second set of columns is conductively coupled to the first end of a first adjacent column of the second set of columns and isolated from the first end of a second adjacent column of the second set of columns, where the first set of interconnecting tracks of conductive material for the second set of conductive columns are electrically insulated from the first set of interconnecting tracks of conductive material for the first set of conductive columns. I/O pads for wire bonding/flip chip may also be connected at this stage. In step <NUM>, a second support substrate is mounted to the first set of tracks of conductive material and the structure is inverted. In step <NUM>, the first support substrate is removed. In step <NUM>, the surface of a second end of each column is planarized in order to remove the horizontally-oriented material between each column. In step <NUM>, the columns are connected with a second set of interconnecting conductive tracks such that a second end of each intermediate column of the first set of columns is conductively coupled to the second end of the second adjacent column of the first set of columns and not coupled to the second end of the first adjacent column of the first set of columns and a second end of each intermediate column of the second set of columns is conductively coupled to the second end of the second adjacent column of the second set of columns and not coupled to the second end of the first adjacent column of the second set of columns, where the second set of interconnecting tracks of conductive material for the second set of conductive columns are electrically insulated from the second set of interconnecting tracks of conductive material for the first set of conductive columns. I/O pads for wire bonding/flip chip may also be connected at this stage.

In the embodiments shown in Figures <NUM> and <FIG>, the conductive columns are located on square vertices. However, any other suitable arrangement of columns could equally well be used. For example, to pack columns more densely, the columns could be arranged in a honeycomb structure or connected in double helix form where the I/O pads are on adjacent columns to ease routing in the electrical circuit. A double helix form corresponds to two interleaved inductor devices that wind around each other like individual strands of deoxyribonucleic acid (DNA). The double-helical strands will ideally have a spiral topology, winding from a common centre outwards. The double-helical topology would have a reduced cross-sectional area, as opposed to a conventional toroidal structure, and the cross-section itself would consist of either an air core or a magnetic core, which would be in addition to the magnetic core which may or may not surround each of the individual columns. This double-helical form would result in the highest inductance with regards to topology. Additionally, a space-filling arrangement of the columns, such as for example, a curve, could also be used in order to ease routing.

The inductor device discussed above provides a number of advantages over conventional planar structures. Firstly, and if considered as an inductor, the inductor device achieves high performance because of excellent coupling (that is, extremely low leakage inductance) and high efficiency. The structure has been found to offer <NUM>% higher inductance for the same coil length when compared to existing V-groove inductors. For example, the inductor structure of Figure <NUM> with one Ni<NUM>Fe<NUM> lamination with a <NUM> thick RDL layer achieves L=<NUM>. 9nH, L/DCR=<NUM>. 39nH/mΩ and L/Footprint=<NUM>. 9nH/mm<NUM> at the frequency of <NUM>, with a Q-factor of <NUM>. The saturation current of this structure is <NUM>. 8A, which gives a current density of <NUM>. 3A/mm<NUM>. In this regard, it should be noted that increasing the diameter of the conductive columns reduces the copper resistance and inductance of the columns, both, thus increasing the saturation current. In the embodiment where the top and bottom conductive tracks are coated with magnetic thin film, a <NUM>% inductance boost is also achieved.

Furthermore, if the inductor is implemented using copper columns embedded in magnetic material laminate, the inductance is increased by more than an order of magnitude (approximately <NUM> times).

Where a laminated magnetic core is used, there is no dielectric material on the flux path, which reduces core losses. Furthermore, copper losses are significantly reduced with vertical current flow, which leads to higher inductor efficiency. In addition, there is no flux crowding, due to the smooth core shape.

In addition, as the first generation of integrated power converter products are based on <NUM>. 5D and 3D stack integration technologies, the present invention facilitates achieving efficient, high density in-package IVRs.

When the inductor structure is integrated into an integrated voltage regulator circuit, the interconnections between different components on the circuit are being used to act as passive devices in the form of inductors. This results in a fully integrated VR solution where the active circuitry is either monolithically built or packaged with the passive devices, that is the inductors and capacitors. Further, the inductor structure uses its magnetic core to improve the power density and efficiency of the IVR circuit.

<FIG> shows another embodiment of the inductor device that does not form part of the present invention. In this embodiment, the supporting structure comprises a passivation layer, as was the case for <FIG>. However, in <FIG> the width of the passivation layer was much smaller than the width of the magnetic layer, whereas in the embodiment of <FIG>, the passivation layer is far greater than the width of the magnetic layer.

<FIG> shows another embodiment of the inductor device that does not form part of the present invention, where the supporting structure comprises a combination of the interconnecting tracks of conductive material and a passivation layer. It should be noted that the interconnect can support the device due to the short distance (small volume) between the conductive columns.

<FIG> shows another embodiment of the inductor device that does not form part of the present invention, where the supporting structure comprises the interconnecting tracks of conductive material and the conductive columns. In this embodiment, air is used as a dielectric. However, it should be noted that this device is not an air core inductor. This embodiment is discrete and self-supporting, as the small length of the interconnecting tracks results in tiny voids between the columns of conductive material, which overall closely approximates a solid structure with a continuous cross-section.

<FIG> shows a top down view of the inductor array of Figure <NUM>. It can be seen that in this embodiment, the columns of conductive material embedded in the supporting structure (not shown) are separated by an interstitial medium. In this regard it should be understood that the supporting structure comprises the material which provides the mechanical strength of the device. A mechanically strong device is synonymously described as being either discrete or self-supporting, or both. A discrete and/or self-supporting device is thus able to "stand on its own" without being supported by any external forces or bodies, such as for example a semiconducting substrate or a printed circuit board.

The interstitial medium comprises the material that fills the vertically-oriented space between the columns of conductive material. It should be noted that the supporting structure and the interstitial medium may or may not be the same material, depending on the embodiment. Thus, <FIG> and <FIG> also comprise columns of conductive material embedded in a supporting structure and separated by an interstitial medium. The interstitial medium may be a gas, a magnetic material or a non-conductive and non-magnetic material. For example, the interstitial medium comprises a gas in the embodiment of <FIG>, while the supporting structure comprises the interconnecting tracks of conductive material and the columns of conductive material. However, in the embodiment of <FIG>, the supporting structure and the interstitial medium both comprise the same material, which is a non-conductive and non-magnetic material.

<FIG> comprises a variation of the embodiment of <FIG>. In this embodiment, the rings of magnetic material comprise magnetic particles suspended in a polymer matrix.

It will be appreciated from the embodiments of <FIG> that the supporting structure of these embodiments is not a conventional substrate.

Therefore, the supporting structure is not a semiconductor, glass or a PCB material.

The coupling factor between two inductors can be tuned by varying the width of the adjoining dielectric. For example, the width of the dielectric material shown in <FIG> can be adjusted to tune the coupling between the inductors to a desired value.

In the device of the present invention, the magnetic anisotropy direction is partially a function of the aspect ratio (AR) of the conductive columns, i.e. the ratio of the height of a conductive column to the diameter of a conductive column. This difference in magnetic anisotropy is illustrated for a conductive column having a first aspect ratio in <FIG> and for a conductive column having a second higher aspect ratio in <FIG>.

The three different orientations of magnetic anisotropy are shown in the Figure: circumferential easy-axis (curling counter-clockwise arrow), radial, and axial (vertical), with probable orientations being shown in green while improbable orientations are shown in red. Thus, it can be seen that for a high aspect ratio, the axial direction becomes much more likely, as shown in <FIG>. It has been found that at AR=<NUM> and beyond, the magnetic anisotropy orientation shown in <FIG> becomes increasingly probable.

In the specification the terms "comprise, comprises, comprised and comprising" or any variation thereof and the terms "include, includes, included and including" or any variation thereof are considered to be totally interchangeable and they should all be afforded the widest possible interpretation and vice versa.

Claim 1:
A transformer or a coupled inductor device comprising:
two interconnected vertical columns of conductive material extending from a substrate and embedded in a supporting structure, the two interconnected vertical columns comprising a first column and a second column spaced apart from the first column, each column comprising an inner column portion and an outer column portion concentric with the inner column portion,
the outer column portion and the inner column portion each having a first end and a second end, wherein the first end of the first inner column portion and the first outer column portion each comprise an input terminal or an output terminal and the first end of the second inner column portion and the second outer column portion each comprise an input terminal or an output terminal, and
wherein the second end of the first inner column portion is conductively coupled to the second end of the second inner column portion by an inner interconnecting track of conductive material, and wherein the second end of the first outer column portion is conductively coupled to the second end of the second outer column portion by an outer interconnecting track of conductive material; characterised in that
the device further comprises a first magnetic layer surrounding each outer column portion and a second magnetic layer surrounding each inner column portion, wherein
the first and second magnetic layers comprise a plurality of vertical laminations comprising alternating magnetic and dielectric layers, wherein the second magnetic layer is provided between each inner column portion and outer column portion.