IT202000028775A1 - INTEGRATED TRANSFORMER SUITABLE FOR OPERATING AT HIGH VOLTAGES AND RELATED MANUFACTURING PROCEDURE - Google Patents

Description

DESCRIPTION

of the patent for Industrial Invention entitled:

?INTEGRATED TRANSFORMER SUITABLE FOR OPERATING AT HIGH VOLTAGES AND RELATED MANUFACTURING PROCEDURE?

The present invention ? relating to an integrated transformer capable of operating at high voltages and to the relative manufacturing process.

As known, transformers are widely used in a wide range of applications; are they, for example, incorporated in appliances in which ? required galvanic isolation, signal transfer and/or power transfer.

In particular, transformers integrated in a die of semiconductor material are known, which are manufactured using manufacturing processes common in the semiconductor industry, for example typical of CMOS technology.

For example, figures 1 and 2 show a transformer 1, which ? made on a chip 5 of semiconductor material and comprises a magnetic core 15, in the shape of a bar, a primary solenoid 10 and a secondary solenoid 12.

The primary solenoid 10 and the secondary solenoid 12 wrap around the magnetic core 15 so as to be interleaved with each other.

The primary solenoid 10 and the secondary solenoid 12 are made of metallic material and extend over a first dielectric layer 18, which insulates them electrically from the plate 5.

The primary solenoid 10 includes first and second contact pads 20, 22 and ? formed by a plurality of upper portions 24, from a plurality? of lower portions 26 and a plurality? of primary routes 28.

The upper portions 24 and lower portions 26 of the primary solenoid 10 each extend successively between the first and second contact pads 20, 22 above and below the magnetic core 15, respectively.

Each upper portion 24 of the primary solenoid 10 ? in direct electrical connection with a respective previous lower portion 26 and a respective subsequent lower portion 26, via respective primary ways 28.

Similarly, the secondary solenoid 12 includes third and fourth contact pads 32, 34 and ? formed by a plurality of respective upper portions 36, from a plurality? of respective lower portions 38 and a plurality? of secondary streets 40.

The upper portions 36 and lower portions 38 of the secondary solenoid 12 each extend successively between the third and fourth contact pads 32, 34 above and below the magnetic core 15, respectively.

Each upper portion 36 of the secondary solenoid 12 ? in direct electrical connection with a respective previous lower portion 38 and a respective subsequent lower portion 38, via respective secondary ways 40.

In detail, each upper portion 24 of the primary solenoid 10 crosses above a corresponding lower portion 38 of the secondary solenoid 12, on the opposite side with respect to the magnetic core 15.

Each lower portion 26 of the primary solenoid 10 crosses below a corresponding upper portion 36 of the secondary solenoid 12, on the opposite side with respect to the magnetic core 15.

In other words, the upper portions 24 of the primary solenoid 10 are each disposed adjacent, at a close distance, for example less than 100?m, to one or more? upper portions 36 of the secondary solenoid 12 and the lower portions 26 of the primary solenoid 10 are each disposed adjacent, at a close distance, e.g., less than 100 µm, to one or more? lower portions 38 of the secondary solenoid 12.

The transformer 1 also comprises a second dielectric layer 43, which extends over the first dielectric layer 18 and laterally surrounds the lower portions 26 of the primary solenoid 10 and the lower portions 38 of the secondary solenoid 12; a third dielectric layer 45, which extends over the second dielectric layer 43 and ? arranged between the magnetic core 15, the lower portions 26 of the primary solenoid 10 and the lower portions 38 of the secondary solenoid 12; a fourth dielectric layer 49, which extends over the third dielectric layer 45 and over the magnetic core 15, laterally surrounding the primary vias 28 and the secondary vias 40, and laterally and above the magnetic core 15; and a fifth dielectric layer 52, which extends over the fourth dielectric layer 49 and laterally and superiorly surrounds the upper portions 24 of the primary solenoid 10 and the upper portions 36 of the secondary solenoid 12.

In use, electrical power is transferred from the primary solenoid 10 to the secondary solenoid 12, which are inductively coupled through the magnetic core 15. As known, a variable current fed into the primary solenoid 10, for example by applying a primary voltage between the first and second contact pad 20, 22, generates a changing magnetic field in the magnetic core 15, which then induces a secondary voltage in the secondary solenoid 12, between the third and fourth contact pads 32, 34.

In specific applications, for example in the automotive and industrial sectors, the primary voltage can assume a high value, for example of a few kilovolts, even up to 20 kV.

As described above, the upper portions 24 of the primary solenoid 10 and the upper portions 36 of the secondary solenoid 12 are arranged in close proximity to each other. Similarly, the lower portions 26 of the primary solenoid 10 and the lower portions 38 of the secondary solenoid 12 are also in close proximity.

The transformer 1 therefore has a high risk of breakage (?breakdown?) of the second, third, fourth and fifth dielectric layers 43, 46, 49, 52, which electrically insulate the primary solenoid 10 and the secondary solenoid 12. The breakage of these dielectric layers cause a short circuit between the primary solenoid 10 and the secondary solenoid 12, with consequent malfunction and/or breakdown of the transformer 1.

Purpose of the present invention? that of overcoming the drawbacks of the prior art.

According to the present invention a transformer and a relative manufacturing process are provided as defined in the attached claims.

For a better understanding of the present invention, embodiments thereof are now described, purely by way of non-limiting example, with reference to the attached drawings, in which:

- figure 1 shows a top view of a known integrated transformer;

figure 2 shows a cross section of the integrated transformer of figure 1, taken along the section line II-II of figure 1;

- figure 3 shows a top view of the present integrated transformer, according to an embodiment;

figure 4 shows a cross section of the integrated transformer of figure 3, taken along the section line IV-IV of figure 3;

- figures 5-11 show cross sections of the integrated transformer of figures 3 and 4 in successive manufacturing phases, taken along the section line IV-IV of figure 3;

- figure 12 shows a top view of the present integrated transformer, according to a different embodiment; And

- figure 13 shows a cross section of the present integrated transformer, according to a further embodiment.

Figures 3 and 4 show a transformer 100 integrated in a chip (?die?) 105 of semiconductor material, for example silicon. The transformer 100 comprises a magnetic core 110 having first and second portions 118, 123, a primary solenoid 115 wound around the first portion 118 of the magnetic core 110 and a secondary solenoid 121 wound around the second portion 123 of the magnetic core 110.

The magnetic core 110, ? formed, here, of a respective adhesion layer (?wetting?) 110A, for example of aluminum, useful in the manufacturing phase, and of a respective magnetic layer 110B, for example of a nickel-iron, cobalt, nickel alloy , neodymium, or other alloys including rare earth or ferroelectric materials.

The magnetic core 110 has for example a toroidal shape, here a rectangular ring in a plane XY of a Cartesian reference system XYZ, and surrounds a hole 125 having an extension W, taken parallel to a first axis X of the Cartesian reference system XYZ , for example between 0.5 mm and 2 mm, in particular about 1 mm. The first and second portions 118, 123 of the magnetic core 110 extend on opposite sides with respect to the hole 125, here symmetrically with respect to an axis of symmetry A parallel to a second axis Y of the Cartesian reference system XYZ.

In this embodiment, the magnetic core 110 is formed by a first structure 126A and a second structure 126B, each having a toroidal shape, in particular here of a rectangular ring in the XY plane.

The first structure 126A and the second structure 126B are concentric to each other, each have a width, for example taken along the first X axis for a side parallel to the second Y axis, ranging for example between 10 ?m and 100 ?m and thickness , parallel to a third axis Z of the Cartesian reference system XYZ, comprised for example between 1 ?m and 20 ?m.

Furthermore, here, the first and second structures 126A, 126B each form two air gaps 128, interposed between the first and second portions 118, 123 of the magnetic core 110, here symmetrical with respect to the axis of symmetry A.

The primary solenoid 115 and the secondary solenoid 121 are formed by respective lower conductive regions 130, intermediate conductive regions 133 and upper conductive regions 136, as evident in particular from Fig. 4 . The lower conductive regions 130, the intermediate conductive regions conduction 133 and the upper conduction regions 136 are formed respectively in a lower metal layer 130, in an intermediate metal layer 133 and in an upper metal layer 136, with which they share the same reference numerals, for simplicity.

In this embodiment, the lower metal layer 130, the intermediate metal layer 133 and the upper metal layer 136 are each formed by a respective adhesion layer (?wetting?) 130A, 133A, 136A, for example of aluminum, useful in manufacturing step, and by a respective conduction layer 130B, 133B, 136B, for example of copper; each conduction layer 130B, 133B, 136B ? arranged directly above the respective adhesion layer 130A, 133A, 136A and has a thickness for example between 1 ?m and 10 ?m.

Furthermore, here, the upper metal layer 136 also comprises a passivation layer 136C, for example of a nickel-gold alloy, directly overlying the conductive layer 136B.

The lower metal layer 130 and the upper metal layer 136 extend respectively at a height, along the third axis Z, which is lower and higher than the height of the magnetic core 110; the intermediate metal layer 133 ? located approximately at the same height, along the third Z axis, as the magnetic core 110.

Referring again to FIG. 3, the primary solenoid 115 has a first end? 115A and a second end? 115B and includes a plurality? of primary coils 142 which extend in succession between the first and second ends? 115A, 115B of primary solenoid 115.

Each primary coil 142 ? formed by an upper portion 145, which ? formed in the upper metal layer 136 and extends above the first portion 118 of the magnetic core 110; from a lower portion 148, which ? formed in the lower metal layer 130 and extends under the first portion 118 of the magnetic core 110; and by two primary ways 151, which are formed by the upper metal layer 136 and by the intermediate metal layer 133 and which extend along the third axis Z. In detail, one of the two primary ways 151 extends between, and in electrical connection directed with, the upper portion 145 and the lower portion 148 of the same primary coil 142; the other of the two primary paths 151 extends between, and in direct electrical connection with, the lower portion 148 of a primary coil 142 and the upper portion 145 of a subsequent primary coil 142.

The upper portions 145 and the lower portions 148 of the primary solenoid 115 extend, along the first axis X, beyond the magnetic core 110, by an amount, for example between 1 ?m and 30 ?m, much smaller than the width W of hole 125.

The lower portions 148 and the upper portions 145 of the primary coils 142 are formed here by strips each having a width ranging from, for example, 1 µm to 100 µm, which may be chosen in the design phase according to the specific application, for example in relation to a desired electrical resistance value of the primary solenoid 115.

Primary solenoid 115 here has nine primary coils 142; however, the number of primary coils 142 pu? be different, depending on the specific application.

Does the secondary solenoid 121 have a first end? 121A and a second end? 121B and includes a plurality? of secondary coils 155 which extend in succession between the first and second ends? 121A, 121B of the secondary solenoid 121.

Each secondary coil 155 ? formed by an upper portion 158, which ? formed in the upper metal layer 136 and extends over the second portion 123 of the magnetic core 110; from a lower portion 161, which ? formed in the lower metal layer 130 and extends under the second portion 123 of the magnetic core 110; and by two secondary ways 163, which are formed by the upper metal layer 136 and by the intermediate metal layer 133 and which extend along the third axis Z. In detail, one of the two secondary ways 163 extends between, and in electrical connection directed with the upper portion 158 and the lower portion 161 of the same secondary coil 155; the other of the two secondary paths 163 extends between, and in direct electrical connection with, the lower portion 161 of a secondary coil 155 and the upper portion 158 of a subsequent secondary coil 155.

The upper portions 158 and the lower portions 161 of the secondary solenoid 121 extend, along the first axis X, beyond the second portion 123 of the magnetic core 110, by a much smaller amount, for example between 1 ?m and 30 ?m compared to the width W of the hole 125.

The lower portions 161 and the upper portions 158 of the secondary solenoid 121 are formed by strips each having a width ranging from, for example, 1 ?m to 100 ?m, which can be chosen in the design phase according to the specific application, for example in relation to a desired electrical resistance value of the secondary solenoid 121.

The secondary solenoid 121 here has three secondary turns 155; however, the number of secondary turns 155 pu? be different and the stripes forming the secondary turns 155 may have a width equal to or different from the width of the stripes forming the primary turns 142, depending on the specific application, for example based on the desired ratio between a voltage applied to the primary solenoid 115 and the corresponding voltage induced on the secondary solenoid 121.

The transformer 100 further comprises a first plurality? of contact pads, here a first and a second contact pad 166, 168, which are electrically connected to the primary solenoid 115, and a second plurality? of contact pads, here a third and a fourth contact pad 170, 172, which are electrically connected to the secondary solenoid 121.

The first and second contact pads 166, 168 allow the primary solenoid 115 to be electrically connected to a first electric circuit, not shown here; the third and fourth contact pads 170, 172 allow the secondary solenoid 121 to be connected to a second electric circuit, not shown here.

The first and second electrical circuits may be integrated into the chip 105 or integrated into one or more circuits. platelets separated from platelet 105.

In detail, here, the first, second, third and fourth contact pads 166, 168, 170, 172 are formed in a metal contact layer 175, for example copper or formed by a respective stack of metal layers, who ? arranged at a height, along the third axis Z, greater than the upper metal layer 136.

Furthermore, in detail, are the first and second contact pads 166, 168 electrically connected respectively to the first and second ends? 115A, 115B of the primary solenoid 115 through a respective contact way 177A.

Similarly, the third and fourth contact pads 170, 172 are electrically connected at the first and second ends, respectively. 121A, 121B of the secondary solenoid 121 through a respective contact way 177B.

The transformer 100 further comprises a plurality of dielectric layers, shown in transparency in figure 3 and visible in figure 4, which electrically insulate the plate 105, the primary solenoid 115, the secondary solenoid 121 and the magnetic core 110 from each other.

In detail, the transformer 100 comprises a first dielectric layer 180, with a thickness ranging for example from 5 ?m to 50 ?m, arranged between the plate 105 and the lower metal layer 130. The first dielectric layer 180 can? be formed by a single dielectric layer, for example of borophosphosilicate glass (BPSG), or by a stack of dielectric layers, the composition of which can? be chosen in the design phase, for example on the basis of the properties? electrical such as resistance as a function of the frequency of the dielectric materials that compose it.

A second dielectric layer 183, for example of tetraethyl orthosilicate (TEOS) or formed by a stack of dielectric layers, extends over the first dielectric layer 180 and laterally surrounds the lower metal layer 130. In this way it electrically insulates the lower portions 148 of the primary solenoid 115 from the lower portions 161 of the secondary solenoid 121.

A third dielectric layer 186, here of silicon nitride, is arranged between the lower metal layer 130 and the magnetic core 110 and has openings in which portions of the adhesion layer 133A and the conduction layer 133B of the intermediate metal layer 133 extend.

A fourth dielectric layer 189 extends over the third dielectric layer 186, the magnetic core 110 and the intermediate metal layer 133. Here, the fourth dielectric layer 189 is formed by a passivation portion 189A, for example of silicon nitride, directly overlying the intermediate metal layer 133, the third dielectric layer 186 and the magnetic core 110, and by a dielectric portion 189B, for example of tetraethyl orthosilicate, directly overlying the passivation portion 189A. The fourth dielectric layer 189 has openings into which portions of the adhesion layer 136A and the conduction layer 136B of the upper metal layer 136 extend.

A fifth dielectric layer 192 extends over the upper metal layer 136, in particular over the passivation layer 136C, and over the dielectric portion 189B of the fourth dielectric layer 189.

Accordingly, the primary vias 151 and secondary vias 163 extend through the fourth dielectric layer 189 and the contact vias 177A, 177B (not visible in Figure 4 ) extend through the fifth dielectric layer 192.

In use, a primary current ? supplied in the primary solenoid 115, for example by applying a primary voltage between the first and second contact pads 166, 168. The primary voltage (and therefore also the primary current) can? be variable over time, for example pu? have an operating frequency, for example in the order of megahertz.

The primary current generates a changing magnetic field in the first portion 118 of the magnetic core 110, and thus a changing magnetic flux extending into the magnetic core 110. The changing magnetic flux portion at the second portion 123 of the magnetic core 110 induces, according to the Faraday-Neumann-Lenz law, a secondary voltage in the secondary solenoid 121, between the third and fourth contact pads 170, 172.

The transformer 100 ? able to function correctly even if the primary voltage assumes a high value, for example up to 20 kV. In fact, the primary solenoid 115 and the secondary solenoid 121 are arranged at a large distance from each other and electrically separated from each other by the first, second, third, fourth and fifth dielectric layers 180, 183, 186, 189, 192, as described above. Consequently, the risk of failure of the first, second, third, fourth and fifth dielectric layers 180, 183, 186, 189, 192 ? reduced, even at high voltages.

The transformer 100 also has a high inductive coupling between the primary solenoid 115 and the secondary solenoid 121. Indeed, the loss (?leakage?) of flux due to the eddy currents (?eddy currents?, or Foucault currents) induced in the magnetic core 110 from the variable magnetic flux, ? reduced thanks to the presence of the first and second structures 126A, 126B.

In fact, the first and second structures 126A, 126B of the magnetic core 110 each have a smaller cross section, in a plane XZ of the Cartesian reference system XYZ, and therefore a higher electrical resistance, than in the case in which the magnetic core ? full (?solid?).

Furthermore, the air gaps 128 allow to avoid unwanted short circuits between the primary solenoid 115 and the secondary solenoid 121 and to reduce the loss of flux due to the divergence of the magnetic flux lines.

In fact, as verified by simulations performed by the Applicant, the air gaps 128, here each having a width of 1 µm, do not cause magnetic flux losses. However, even wider air gaps, for example up to 100 µm, do not involve losses in the inductive coupling efficiency between the primary solenoid 115 and the secondary solenoid 121. In fact, the difference between the permeability? magnet of the magnetic core 110, which ? much greater than 1, and the permeability? magnetic field of the first, second, third, fourth and fifth dielectric layer 180, 183, 186, 189, 192, which ? close to 1, ? elevated. Consequently, the loss of magnetic flux in the first, second, third, fourth and fifth dielectric layers 180, 183, 186, 189, 192 due to the air gaps 128 ? negligible.

The manufacturing steps of the transformer 100 are described below.

Figure 5 shows a working body 300 comprising a wafer 305 of semiconductor material, which has a front side delimited by a surface 305A. On the surface 305A ? already Was the first dielectric layer 180 formed, for example by deposition of one or more? dielectric layers, as described above.

In Fig. 6 , the bottom metal layer 130 is formed, over the first dielectric layer 180. In detail, here, the bottom metal layer 130 is formed. formed by deposition and definition of the respective adhesion layer 130A and subsequent formation, for example by electrochemical deposition, of the respective conduction layer 130B. Furthermore, the second dielectric layer 183 ? deposited on the front side of the body of work 300 and ? defined, for example through known planarization procedures, so as to laterally surround the lower metal layer 130.

Next, figure 7 , the third dielectric layer 186 is deposited over the second dielectric layer 183 and over the lower metal layer 130 and shaped so as to form a first plurality of of openings 315, above portions of the lower metal layer 130 where it is intended to form the primary ways 151 and the secondary ways 163.

In figure 8 , the intermediate metal layer 133 is formed on the second dielectric layer 186. In detail, the intermediate metal layer 133 is formed by deposition and definition of the respective adhesion layer 133A and subsequent formation, for example by electrochemical deposition, of the respective conduction layer 133B. In particular, the intermediate metal layer 133 comprises regions extending through the first plurality of of openings 315 and are here in direct electrical contact with the lower metal layer 130. Furthermore, the magnetic core 110 is formed on the second dielectric layer 186, for example by deposition and definition of the respective adhesion layer 110A and subsequent formation, for example by electrochemical deposition, of the respective magnetic layer 110B. For example, the adhesion layer 110A of the magnetic core 110 could be made simultaneously with the adhesion layer 133A of the intermediate metal layer 133.

In figure 9 the fourth dielectric layer 189 is formed, here by deposition of the passivation portion 189A on top of the third dielectric layer 186, the intermediate metal layer 133 and the magnetic core 110, and deposition and planarization of the dielectric portion 189B, directly overlying the of passivation 189A.

Subsequently, figure 10, a second plurality? of openings 320 ? formed across the fourth dielectric layer 189, over the intermediate conduction regions 133, which are then exposed.

In Figure 11 , the top metal layer 136 is formed on the fourth dielectric layer 189. In detail, the upper metal layer 136 is formed through deposition and definition of the respective adhesion layer 136A and subsequent formation, for example by electrochemical deposition, of the respective conduction layer 136B and of the respective passivation layer 136C, so that the upper conduction regions 136 are in direct electrical contact with the intermediate conduction regions 133, through the second plurality? of openings 320. In this way, the upper portions 145 of the primary coils 142, the upper portions 158 of the secondary coils 155, and, together with the steps illustrated in figures 7-10, the primary vias 151 and the secondary vias 163 are formed.

In a not shown but known way, the fifth dielectric layer 192 is then formed and subsequently the first, second, third and fourth contact pads 166, 168, 170, 172 are formed.

Known processing steps follow, such as for example cutting (?dicing?) of the working body 300 and encapsulation of the corresponding plate, so as to form the transformer 100.

Figure 12 shows a different embodiment of the present transformer. In particular, Figure 12 shows a transformer 400 having a general structure similar to that of the transformer 100 shown in Figure 3; as a result, elements in common have the same reference numerals.

In detail, here too the 400 transformer? formed in the chip 105 and includes a magnetic core 410, the primary solenoid 115, which is wound around a first portion 415 of the magnetic core 410, the secondary solenoid 121, which is wrapped around a second portion 418 of the magnetic core 410, and a plurality of dielectric layers similar to the first, second, third, fourth and fifth dielectric layers 180, 183, 186, 189, 192 shown in figure 4 in relation to the transformer 100 and not shown here.

Again, the plurality? of dielectric layers electrically insulates the plate 105, the primary solenoid 115, the secondary solenoid 121 and the magnetic core 410 from each other.

Again, the primary solenoid 115 comprises the plurality of primary turns 142, and the secondary solenoid 121 comprises the plurality of secondary turns 155. The primary turns 142 are formed by the respective upper portions 145, lower portions 148 and primary vias 151; and the secondary coils 155 are formed by the respective upper portions 158, lower portions 161 and secondary vias 163.

The magnetic core 410 has a toroidal shape, also here of a rectangular ring in the XY plane, and is? formed by a first structure 420A and a second structure 420B, concentric with each other.

In this embodiment, the first and second structures 420A, 420B each form a plurality of structures. of air gaps, here three air gaps 423A-423C on each side, arranged in succession in threes. Each air gap 423A-423C has a width, parallel to the second axis Y, ranging for example from 1 ?m to 100 ?m.

The air gaps 423A-423C allow the first portion 415 to be further spaced from the second portion 418 of the magnetic core 410 (and therefore the primary solenoid 115 from the secondary solenoid 121) using a reduced amount of magnetic material, compared to the 100 transformer.

Consequently, the probability breaking, in use, of the plurality? of dielectric layers? further reduced.

Additionally, the air gaps 423 also help to further reduce the eddy currents in the magnetic core 410.

As a result, the 400 transformer has high inductive coupling and high reliability.

The 400 transformer can? be made starting from the working body 300 of figure 5, in a similar way to what is described with reference to figures 5-11 for the transformer 100.

Figure 13 shows a different embodiment of the present transformer. In particular, Figure 13 shows a transformer 500 having a general structure similar to that of the transformer 100 shown in Figures 3 and 4; as a result, elements in common have the same reference numerals.

In detail, the transformer 500 ? formed in a plate 505 of insulating material, for example of glass, and comprises the magnetic core 110, the primary solenoid 115 (here shown only in part) and the secondary solenoid (here not shown).

The primary solenoid 115 and the secondary solenoid are also formed here by the lower metal layer 130, the intermediate metal layer 133 and the upper metal layer 136.

The transformer 500 also comprises the second, third, fourth and fifth dielectric layers 183, 186, 189, 192, which electrically insulate the primary solenoid 115, the secondary solenoid and the magnetic core 110 from each other.

In this embodiment, the bottom metal layer 130 is in direct contact with plate 505.

In other words, the transformer 500 does not include the first dielectric layer 180 shown in Fig. 4 ; the plate 505 ? in fact, of insulating material and not ? it is therefore necessary to use an additional insulating layer to electrically insulate the primary solenoid 115, the secondary solenoid 121 and the plate 505 from each other.

Consequently, the 500 transformer guarantees reliability of operation and has a lower manufacturing cost.

The 500 transformer can? be made starting from a working body of insulating material, for example glass, on which the manufacturing steps described with reference to figures 6-11 in relation to the transformer 100 can be performed.

Finally, it is clear that modifications and variations can be made to the transformer 100, 400, 500 and to the relative manufacturing process described and illustrated herein without thereby departing from the protective scope of the present invention, as defined in the attached claims.

For example, the different embodiments described can be combined to provide further solutions.

Also, the magnetic core 110, 410 can? be formed by a different number of structures, for example by a single structure, or by a number of structures greater than two.

For example, the magnetic core 110, 410 can? have the shape of a continuous torus, i.e. without air gaps.

The magnetic core 110, 410 pu? also have a different toroidal shape than shown in figures 3 and 12; for example can? have in the XY plane the shape of a square, round, regular or irregular polygonal ring, or any other shape delimiting the hole 125.

Finally, a greater number of contact pads can be used, for example, additional contact pads can be arranged at portions between the first and second ends? of the secondary solenoid, in order to obtain induced secondary voltages of different values.

Claims (15)

1. Integrated transformer (100; 400; 500) including: a first insulating region (180; 505); a second insulating region (183, 186, 189, 192) extending over the first insulating region; a magnetic core (110; 410) extending inside the second insulating region at a first height and comprising a first core portion (118; 415) and a second core portion (123; 418), distinct from each other; a first winding (115) extending into the second insulating region (183, 186, 189, 192) and wound around the first core portion (118; 415); And a second winding (121) extending inside the second insulating region (183, 186, 189, 192) and wound around the second core portion (123; 418). 2. Integrated transformer according to the preceding claim, wherein the first winding (115) comprises a first plurality of turns (142) and the second winding (121) comprises a second plurality? of coils (155), in which each coil (142) of the first plurality? of coils? formed by a first primary portion (148), by a second primary portion (145) and by a primary connection way (151), the first primary portion extending into the second insulating region (183, 186, 189, 192) to a second height less than the first height, the second primary portion extending into the second insulating region to a third height greater than the first height, the primary connection path (151) extending through the second insulating region between and in direct electrical connection with the first primary portion and the second primary portion; and in which each coil (155) of the second plurality? of coils? formed by a first secondary portion (161), by a second secondary portion (158) and by a secondary connection way (163), the first secondary portion extending into the second insulating region at the second height, the second secondary portion extending into the second region insulating at the third height, the secondary connection via extending through the second insulating region between and in direct electrical connection to the first and second secondary portions. 3. Integrated transformer (100; 400; 500) according to any one of the preceding claims, wherein the magnetic core (110; 410) is formed by a plurality of toroidal structures (126A, 126B; 420A, 420B), each toroidal structure being concentric with and electrically isolated from an adjacent toroidal structure. 4. Integrated transformer (100; 400; 500) according to any one of the preceding claims, wherein the magnetic core (110; 410) comprises at least one air gap (128; 423A-423C), the at least one air gap being formed by a? end? of the first core portion (118; 415) and a? extremity? of the second portion of the nucleus (123; 418), the? Extremity? of the first portion of the core and the? extremity? of the second core portion facing each other. 5. Integrated transformer according to the preceding claim, wherein the at least one air gap has a minimum width along a first direction (X) comprised between 1 ?m and 100 ?m. 6. Integrated transformer (400) according to claim 4 or 5, wherein the at least one air gap ? a first air gap (423A), the integrated transformer comprising a second air gap (423B), the second air gap being disposed between the end? of the first portion of the core and the? extremity? of the second core portion. 7. Integrated transformer according to any one of the preceding claims, wherein the second insulating region comprises a plurality of of insulating layers (183, 186, 189, 192) arranged superimposed on each other. The integrated transformer (500) according to any one of the preceding claims, wherein the first insulating region comprises a glass body (505). The integrated transformer (100; 400) according to any one of claims 1-7, wherein the first insulating region (180) extends over a semiconductor substrate (105). 10. Manufacturing process of an integrated transformer (100; 400; 500) comprising: forming, on a first insulating region (180; 505), a second insulating region (183, 186, 189, 192); forming a magnetic core (110; 410) in the second insulating region, at a first height, the magnetic core comprising a first core portion (118; 415) and a second core portion (123; 418), distinct from each other; forming a first winding (115) in the second insulating region (183, 186, 189, 192), the first winding being wound around the first core portion (118; 415); And forming a second winding (121) in the second insulating region (183, 186, 189, 192), the second winding being wound around the second core portion (123; 418). The method according to claim 10, wherein forming the first winding (115) comprises forming a first plurality of coils (115). of turns (142) and forming the second winding comprises forming a second plurality? of coils, each coil (142) of the first plurality? of coils being formed by a first primary portion (148), by a second primary portion (145) and by a primary connection path (151), each coil (155) of the second plurality? of coils being formed by a first secondary portion (161), by a second secondary portion (158) and by a secondary connection path (163), in which to form the first and second plurality? of coils includes: forming, on the first insulating region (180; 505), at a second height lower than the first height, the first primary portions (148) and the first secondary portions (161), starting from a first metal layer (130); forming, on the first metal layer, at the first height, the primary connection ways (151) and the secondary connection ways (163), starting from a second metal layer (133); forming, on the second metal layer, at a third height greater than the first height, the second primary portions (145) and the second secondary portions (158), starting from a third metal layer (136). 12. A method according to the preceding claim, wherein forming a second insulating region comprises forming a plurality of insulating regions. of insulating layers comprising a first insulating layer (183, 186), a second insulating layer (189) and a third insulating layer (192), the first insulating layer, the second insulating layer and the third insulating layer being arranged in succession one above the other is wherein forming a magnetic core (110; 410) comprises forming a layer of magnetic material (110B); wherein the first insulating layer surrounds the first primary portions (148) and the first secondary portions (161), the second insulating layer surrounds the primary vias (151), the secondary vias (163) and the magnetic core ( 110; 410), and the third insulating layer surrounds the second primary portions (145) and the second secondary portions (158). 13. A method according to any one of claims 10-12, wherein forming a magnetic core comprises forming a plurality of magnetic cores. of toroidal structures (126A, 126B; 420A, 420B), each toroidal structure being concentric with and electrically isolated from an adjacent toroidal structure. The method according to any one of claims 10-13, wherein the first insulating region comprises a glass body. The method according to any one of claims 10-13, wherein the first insulating region (180) extends over a semiconductor substrate (305).