Eight-shaped inductor

Abstract

Figure-eight inductor This description relates to a figure-eight inductor (300), comprising in a first conductive layer: - an outer loop (318) of a first part (308) of the inductor connected to a first outer partial loop (310a) of a second part (308) of the inductor and further connected to one or more inner loops (326) of the first part, the outer loop and the inner loops of the first part being concentric; and - one or more inner loops (334) of the second part connected to a second outer partial loop (310b) of the second part, the outer partial loops and the inner loops of the second part being concentric;the inductor further comprising a conductive link (330) which connects the inner loops of the first part to the inner loops of the second part, the conductive link being partially in a second conductive layer. Figure for the abbreviation: Fig. 3;

Description

Title of the invention: Figure-eight shaped inductor technical field

[0001] This description relates generally to inductors and, in particular, to figure-eight inductors, methods of using figure-eight inductors and methods of manufacturing figure-eight inductors. Previous technique

[0002] An inductor is an electronic component comprising one or more conductive loops connected in series between two conduction terminals, sometimes called the ends of the inductor. The inductance value, expressed in Henrys, represents the inductor's ability to store energy in the form of a magnetic field when an electric current flows through it. The greater the number of loops in the inductor, the higher the inductance value.

[0003] However, the magnetic field irradiated by an inductor can cause undesirable coupling with nearby electronic components. Figure-eight inductors were developed to reduce mutual parasitic inductance, i.e., magnetic coupling with other devices, while still offering high self-inductance values. The article entitled "Reduction of Inductive Crosstalk Using Quadrupole Inductors" by A. Poon et al., published in 2009 in the IEEE Journal of Solid-State Circuits, describes in detail the advantages of figure-eight inductors.

[0004] In microelectronic circuits, the loops of an induction coil are materialized by conductive traces in a stack of conductive and insulating layers on a substrate. When two conductive traces of a given loop formed in a given conductive layer of the stack need to cross, a link is formed using vias and a portion of trace in another conductive layer to form a bridge. However, a disadvantage of figure-eight inductors is that they tend to include a relatively high number of such links, leading to a low quality factor of the inductor.

[0005] There is a need for an improved figure-eight shaped inductor. Summary of the invention

[0006] According to one embodiment, a figure-eight shaped inductor is provided, comprising: in a first conductive layer of a stack of insulating and conductive layers: - an outer loop of a first part of the inductor having a first end connected to an end of a first outer partial loop of a second part of the inductor and a second end connected to a first end of one or more inner loops of the first part of the inductor, the outer loop and the one or more inner loops of the first part being concentric; and - one or more inner loops of the second part of the inductor having a first end connected to one end of a second outer partial loop of the second part of the inductor, the first and second outer partial loops and the one or more inner loops of the second part of the inductor being concentric; the inductor further comprising a conductive link which connects a second end of one or more inner loops of the first part of the inductor to a second end of one or more inner loops of the second part of the inductor, the conductive link being partially in a second conductive layer.

[0007] According to one embodiment, a current applied between a first terminal and a second terminal of the inductor flows in a first direction of rotation in the outer loop and in the one or more inner loops of the first part of the inductor and in a second direction of rotation opposite to the first direction in the first and second outer partial loops and in the one or more inner loops of the second part.

[0008] According to one embodiment, in the first part, a first width of the outer loop is greater than a second width of the one or more inner loops and in which, in the second part, a third width of the first and second outer partial loops is greater than a fourth width of the one or more inner loops.

[0009] According to one embodiment, the second conductive layer is closer to the substrate than the first conductive layer.

[0010] According to one embodiment, the first conductive layer is closer to the substrate than the second conductive layer.

[0011] According to another aspect, an integrated circuit is planned comprising at least one inductor as described above.

[0012] According to another aspect, a voltage-controlled oscillator is provided comprising at least one inductor as described above.

[0013] According to another aspect, an emitter is provided comprising at least one inductor as described above.

[0014] According to another aspect, a process is envisaged comprising: - the application of a current, via an electronic circuit, to a figure-eight shaped inductor, comprising: in a first conductive layer of a stack of insulating and conductive layers: an outer loop of a first part of the inductor having a first end connected to an end of a first outer partial loop of a second part of the inductor and a second end connected to a first end of one or more inner loops of the first part of the inductor, the outer loop and the one or more inner loops of the first part being concentric; and one or more inner loops of the second part of the inductor having a first end connected to one end of a second outer partial loop of the second part of the inductor, the first and second outer partial loops and the one or more inner loops of the second part of the inductor being concentric; the inductor further comprising a conductive link which connects a second end of one or more inner loops of the first part of the inductor to a second end of one or more inner loops of the second part of the inductor, the conductive link being partially in a second conductive layer; - the transmission of current in the inductor.

[0015] According to one embodiment, - the current is applied to a first terminal of the inductor; - current is transmitted from the first terminal to a second terminal of the inductor; and - current is supplied to the second terminal of the inductor.

[0016] According to another aspect, a method for manufacturing a figure-eight shaped inductor is provided, the method comprising: in a stack of insulating and conductive layers: - the formation, in a first conductive layer of the stack, of an outer loop of a first part of the inductor having a first end connected to an end of a first outer partial loop of a second part of the inductor and a second end connected to a first end of one or more inner loops of the first part of the inductor, the outer loop and the one or more inner loops of the first part being concentric; - the formation, in the first conductive layer of the stack, of one or more inner loops of the second part of the inductor having a first end connected to an end of a second outer partial loop of the second part of the inductor, the first and second outer partial loops and the one or more inner loops of the second part of the inductor being concentric.

[0017] According to one embodiment, the process for manufacturing a figure-eight shaped inductor further comprises, after the formation of the first conductive layer: - the formation of a first via which comes into contact with a second end of one or more inner loops of the first part of the inductor; - the formation of a second via which comes into contact with a second end of one or more inner loops of the second part of the inductor; and - the formation, in a second conductive layer of the stack, of a conductive bond which connects the first via and the second via.

[0018] According to one embodiment, the manufacturing process of a figure-eight shaped inductor further comprises, before the formation in the first conductive layer: - the formation, in a second conductive layer of the stack, of a conductive bond; - the formation of a first via, which comes into contact with a first end of the conductive link and which also comes into contact with a second end of one or more internal loops of the first part of the inductor; and - the formation of a second via, which comes into contact with a second end of the conductive link and which also comes into contact with a second end of one or more inner loops of the second part of the inductor. Brief description of the drawings

[0019] These features and advantages, as well as others, will be described in detail in the following description of particular embodiments, given by way of non-limiting example, in relation to the accompanying figures, among which:

[0020] Fig. 1 represents a structure of a figure-eight shaped inductor that has been proposed, comprising two loops;

[0021] Fig. 2 represents another structure of a figure-eight shaped inductor that has been proposed, comprising four loops;

[0022] [Fig.3] represents a figure-eight shaped inductor comprising four loops according to an embodiment of the present description;

[0023] [Fig.4] represents a figure-eight shaped inductor comprising six loops according to another embodiment of the present description;

[0024] [Fig.5] is a graph illustrating an example of the inductance value of the inductors of [Fig.2] and [Fig.3] as a function of the frequency of an alternating current flowing through them;

[0025] [Fig.6] is a graph illustrating an example of the quality factor of the inductors of [Fig.2] and [Fig.3] as a function of the frequency of an alternating current flowing through them;

[0026] [Fig.7] schematically represents an emitter in which the figure-eight shaped inductor of [Fig.3] or [Fig.4] can be incorporated according to one example of an embodiment of the present description;

[0027] [Fig.8] schematically represents an emitter in which the figure-eight shaped inductor of [Fig.3] or [Fig.4] can be incorporated according to another embodiment of the present description;

[0028] Figure 9 schematically represents an integrated circuit comprising the figure-eight shaped inductor of Figure 3 or Figure 4, according to one embodiment of this description; and

[0029] [Fig. 10] represents a structure of a conductive layer of the figure-eight shaped inductor of [Fig. 3] according to an example of an embodiment of the present description. Description of the implementation methods

[0030] The same elements have been designated by the same reference numerals in the different figures. In particular, the structural and / or functional elements common to the different embodiments may have the same reference numerals and may have identical structural, dimensional and material properties.

[0031] For the sake of clarity, only the steps and elements useful for understanding the described embodiments have been shown and are detailed. In particular, the processes involved in manufacturing an inductor are known to a person skilled in the art and will not be described in detail in this description.

[0032] Unless otherwise specified, when referring to two elements connected together, this means directly connected without intermediate elements other than conductors, and when referring to two elements connected (in English "coupled") together, this means that these two elements can be connected or linked through one or more other elements.

[0033] In the following description, when reference is made to absolute position qualifiers, such as the terms "front", "back", "top", "bottom", "left", "right", etc., or relative position qualifiers, such as the terms "above", "below", "superior", "inferior", etc., or to orientation qualifiers, such as the terms "horizontal", "vertical", etc., reference is made, unless otherwise specified, to the orientation of the figures.

[0034] Unless otherwise specified, the expressions "approximately", "roughly", and "in the order of" mean within 10%, preferably within 5%.

[0035] In the following description, inductors formed in a circuit comprising a stack of insulating and conductive layers covering a substrate are considered. Other electronic components may also be integrated into the circuit and connected to the inductor via conductive tracks in the stack.

[0036] The term "conductive layer" is used here to refer to a single layer of the stack comprising a set of conductive tracks made of a conductive material, for example a metal, for example copper, surrounded by an insulating material, for example silicon oxide.

[0037] The term "loop", when referring to an inductor, is used to designate a single conductive track of the inductor that rotates by at least 270°, or one or more conductive tracks of the same or different conductive layers of the inductor, connected to each other so as to be electrically equivalent to a single conductive track that rotates by at least 270°. Loops can have any shape, for example orthogonal, hexagonal, circular, square, rectangular, etc.

[0038] Fig. 1 represents a structure of a figure-eight shaped inductor that has been proposed, comprising two loops.

[0039] The inductor 100 comprises a first terminal 102 and a second terminal 104, each configured to receive and / or supply current. The figure-eight inductor 100 comprises a first portion 106 of the figure-eight connected to terminals 102 and 104, and a second portion 108 of the figure-eight. The first portion 106 comprises a first partial loop 110a. One end of the first partial loop 110a is connected to the first terminal 102.

[0040] A second end of the first partial loop 110a is connected to a first end of a first conductive link 114. A second end of the first conductive link 114 is connected to a first end of a loop 118 of the second part 108 of the inductor 100. A second end of the loop 118 is connected to a first end of a second conductive link 122. A second end of the conductive link 122 is connected to a first end of a second partial loop 110b of the first part 106. A second end of the second partial loop 110b is connected to the second terminal 104.

[0041] The partial loops 110a and 110b are located in the first part 106 of the inductor and together constitute a loop 110 of the inductor 100. The loops 118 and 110 are connected in series, for example by means of the conductive links 114 and 122 and together define the shape of a figure eight.

[0042] The first terminal 102, the second terminal 104, the loop 110, the first conductive link 114 and the loop 118 are formed in a first conductive layer of the inductor 100.

[0043] The second conductive bond 122 is formed partly in a second conductive layer of the inductor.

[0044] The second conductive link 122 includes a first via at its first end and a second via at its second end to connect the first and second conductive layers.

[0045] The inductive loops of the first part 106 and of the second part 108 are arranged so that a current flows in them with an opposite rotation, in other words the current flows clockwise in one of the loops and counterclockwise in the other loop. For example, when a current flows from terminal 102 to terminal 104 of the inductor, in a direction indicated by arrows in [Fig. 1], the current flows clockwise in loop 110 and counterclockwise in loop 118. Similarly, when a current flows in the opposite direction to the arrows, i.e. from terminal 104 to terminal 102 of the inductor, the current flows counterclockwise in loop 110 and clockwise in loop 118.As the orientation of the magnetic field in each loop changes with the clockwise or counterclockwise direction of current flow, from a certain distance, the magnetic field generated by loop 118 at least partially cancels the magnetic field generated by loop 110. Therefore, inductor 100 has a reduced impact on nearby electronic components.

[0046] Fig. 2 represents another structure of a figure-eight inductor that has been proposed comprising four loops.

[0047] The inductor 200 includes a first terminal 202 and a second terminal 204 which are configured to receive and / or supply current. The figure-eight inductor 200 includes a first portion 206 of the figure-eight connected to terminals 202 and 204, and a second portion 208 of the figure-eight. The first portion 206 includes a first outer partial loop 210a. A first end of the first outer partial loop 210a is connected to the first terminal 202, and a second end of the first outer partial loop 210a is connected to a first end of a first conductive link 214. A second end of the first conductive link 214 is connected to a first end of a first inner partial loop 218a of the second portion 208. A second end of the first inner partial loop 218a is connected to a first end of a second conductive link 220.A second end of the conductive link 220 is connected to a first end of a first outer partial loop 222a of the second part 208. A second end of the first outer partial loop 222a is connected to the first end of a third conductive link 224. A second end of the third conductive link 224 is . connected to the first end of a first inner loop 226 of the first part 206. A second end of the first inner loop 226 is connected to a first end of a fourth conductive link 228. A second end of the conductive link 228 is connected to a first end of a second outer partial loop 222b of the second part 208. A second end of the second outer partial loop 222b is connected to the first end of a fifth conductive link 232. The second end of the fifth conductive link 232 is connected to the first end of a second inner partial loop 218b of the second part 208. A second end of the second inner partial loop 218b is connected to a first end of a sixth conductive link 236.A second end of the conductive link 236 is connected to a first end of a second outer partial loop 210b of the first part 206. A second end of the second outer partial loop 210b is connected to the second terminal 204.

[0048] The outer partial loops 210a and 210b together constitute an outer loop of the first part 206 of the inductor 200. The outer partial loops 222a and 222b together constitute an outer loop 222 of the second part 208 of the inductor 200. The inner partial loops 218a and 218b together constitute an inner loop 218 of the second part 208 of the inductor 200.

[0049] The terminals 202 and 204, the inner and outer loops of the first part 206 and the second part 208 and the conductive links 214, 228 and 232 are formed in a first conductive layer of the inductor 200.

[0050] The three conductive links 220, 224 and 236 are formed partly in a second conductive layer of the inductor 200.

[0051] The inductive loops of the first part 206 and the second part 208 are arranged so that a current flows in them with opposite directions of rotation; in other words, the current flows clockwise in the loops of one part and counterclockwise in the loops of the other part. For example, when a current flows from terminal 202 to terminal 204 of the inductor, in the direction indicated by the arrows in [Fig. 2], the current flows clockwise in the outer loop 210 and in the inner loop 226 of the first part 206 and counterclockwise in the outer loop 222 and in the inner loop 218 of the second part 208.Similarly, when a current flows in the opposite direction to the arrows, i.e. from terminal 204 to terminal 202 of the inductor, the current flows counterclockwise in the outer loop 210 and in the inner loop 226 of the . The first part 206 flows clockwise in the outer loop 222 and in the inner loop 218 of the second part 208. Since the current flows in the same direction in each loop of a given part of the inductor 200, the inductances of these loops add up. However, beyond a certain distance, the magnetic field generated by the first part 206 of the inductor 200 always at least partially cancels out the magnetic field generated by the second part 208 of the inductor 200.

[0052] The inductor 200 has twice the number of loops of the inductor 100 of [Fig.1], so, for similar loop dimensions, its inductance can be about twice that of the inductor 100.

[0053] It will be observed that the inductor 100 of [Fig. 1] has one crossing point, which is defined as a point at which, viewed from above, conductive connections between conductive tracks in the first conductive layer cross each other, and a second conductive layer is used for one of the connections to prevent a short circuit. In contrast, the inductor 200 has three crossing points. Each additional crossing point causes an increase in the resistance and capacitance of the inductor and, consequently, a decrease in the quality factor and an increase in the inductor's energy consumption. The quality factor of an inductor is defined as the ratio of its inductive reactance to its resistance at a given frequency.When the dimensions of inductor 200 are such that its inductance matches that of inductor 100, inductor 200 is considered to have a quality factor reduced by 5 compared to the quality factor of inductor 100, the loss being attributed to the greater number of crossover points. The increase in capacitance arises from the overlap of two conductive tracks at the crossover point. Furthermore, if the second conductive layer is closer to the substrate than the first conductive layer, there is, for example, a higher capacitance between the second conductive layer and the substrate than between the first conductive layer and the substrate.

[0054] Using a structure similar to that of [Fig. 2], but choosing to have six loops instead of four, or in other words, having three loops in each part instead of two, would lead to 8 crossover points. Similarly, there would be 15 crossover points for 8 loops and 24 crossover points for 10 loops. Therefore, the number of crossover points increases non-linearly with the number of loops. This means that, although the inductance value of a figure-eight inductor increases with the increasing number of loops, the quality factor decreases significantly.

[0055] Fig. 3 represents a figure-eight inductor structure comprising four loops according to an embodiment of the present description.

[0056] The inductor 300 is formed in a circuit comprising a stack of insulating and conductive layers covering a substrate (not shown in [Fig.3]).

[0057] The inductor 300 comprises a first terminal 302 and a second terminal 304, which are configured to be connected to other electronic components (not shown in [Fig. 3]), and each is configured to receive and / or supply current. The figure-eight inductor 300 comprises a first portion 306 of the figure-eight connected to terminals 302 and 304, and a second portion 308 of the figure-eight. The first portion 306 comprises an outer partial loop 310a. One end of the outer partial loop 310a is connected to the first terminal 302, and a second end of the outer partial loop 310a is connected to a first end of a first conductive link 314. A second end of the first conductive link 314 is connected to a first end of an outer loop 318 of the second portion 308 of the inductor 300.A second end of the outer loop 318 is connected to a first end of a second conductive link 322. A second end of the second conductive link 322 is connected to a first end of an inner loop 326 of the second part 308. A second end of the inner loop 326 is connected to the first end of a third conductive link 330. A second end of the third conductive link 330 is connected to the first end of an inner loop 334 of the first part 306. A second end of the inner loop 334 is connected to a first end of a fourth conductive link 338. A second end of the conductive link 338.

[0058] The outer partial loops 310a and 310b together constitute an outer loop of the first part 306 of the inductor 300 is connected to a first end of an outer partial loop 310b of the first part 306. A second end of the outer partial loop 310b is connected to the second terminal 304.

[0059] The inductive loops of the first part 306 and the second part 308 are arranged so that a current flows in them with opposite rotations; in other words, the current flows clockwise in the loops of one part and counterclockwise in the loops of the other part. For example, when the current flows from terminal 302 to terminal 304 of the inductor 300 in the direction indicated by the arrows in [Fig. 3], the current flows clockwise in the outer loop 310 and the inner loop 334 of the first part 306, and counterclockwise in the outer loop 318 and the inner loop 326. of the second part 308. Similarly, when a current flows in the opposite direction to the arrows, i.e. from terminal 304 to terminal 302 of the inductor, the current flows counterclockwise in the outer loop 310 and the inner loop 334 of the first part 306 and clockwise in the outer loop 318 and the inner loop 326 of the second part 308.

[0060] Since the current flows in the same direction in each loop of a given portion of the inductor 300, the inductances of these loops add up. The inductor 300 has as many loops as the inductor 200 of [Fig. 2], so their inductances are similar. The inductor 300 is also figure-eight shaped, so the magnetic field generated by the first portion 306 of the inductor is at least partially canceled by the second portion 308 of the inductor, and the mutual inductance of the inductor 300 is relatively low. As a result, parasitic coupling with neighboring electronic components is also relatively low.

[0061] The terminals 302 and 304, the inner and outer loops of the first part 306 and the second part 308 of the inductor 300 and the conductive links 314, 322 and 338 are formed in a first conductive layer of the inductor 300.

[0062] The third conductive bond 330 is formed partly in a second conductive layer of the inductor 300.

[0063] In one embodiment, the second conductive layer is, for example, closer to the substrate than the first conductive layer. The capacitance between the first conductive layer and the substrate is, for example, lower than the capacitance between the second conductive layer and the substrate.

[0064] In other embodiments, the first conductive layer is closer to the substrate than the second conductive layer.

[0065] The third conductive link 330 includes a first via at its first end and a second via at its second end to connect the first conductive layer to the second conductive layer.

[0066] The inductor 300 has four loops, two loops in each part, and a single crossing point: only one conductive bond is located in the second conductive layer. Therefore, when the dimensions of the inductor 300 are such that its inductance corresponds to that of the inductor 200, the inductor 300 has a higher quality factor and lower energy consumption than the inductor 200.

[0067] In one embodiment, the first conductive layer is less resistive than the second layer. Reducing the number of crossover points further reduces the resistance of the inductor 300.

[0068] According to one embodiment, the outer loops 310 and 318 have a first width W1 and the inner loops 326 and 334 have a second width W2. For example, the width W1 is greater than the width W2.

[0069] According to one embodiment, a radius of curvature of the outer partial loops 310a and 310b is similar to the radius of the outer loop 318 and a radius of the inner loop 326 is similar to the radius of the inner loop 334.

[0070] According to one embodiment, the loops 310 and 334 of the first part 306 are concentric and the loops 318 and 326 of the second part 308 are concentric.

[0071] Figure 4 represents a figure-eight inductor structure 400 comprising six loops according to another embodiment of the present description.

[0072] Some elements of [Fig.4] are similar to the elements of [Fig.3]. They are referenced with the same references and will not be detailed again.

[0073] In the case where each part of the figure-eight shaped inductor 400 comprises three or more concentric loops, each of the loops except the outer loop shall be referred to herein as the "inner loop" of the inductor.

[0074] In the following description of [Fig.4], since each part 306, 308 of the inductor 400 comprises three loops, the inner loop 334 of the first part 306 of the inductor 300 is called intermediate loop 334 and the inner loop 326 of the second part 308 of the inductor is called intermediate loop 326.

[0075] Compared to the inductor 300, the first part 306 of the inductor 400 has an additional conductive link 441 and an additional inner loop 440, and the second part 308 of the inductor 400 has an additional conductive link 419 and an additional inner loop 420. The conductive link 419 has a first end connected to the second end of the intermediate loop 326 of the second part 308 of the inductor 400 and a second end connected to a first end of the inner loop 420 of the second part 308. Compared to the inductor 300, the third conductive link 330 of [Fig. 3] now has its first end connected to a second end of the inner loop 420 of the second part 308.The conductive link 441 has a first end connected to the first end of the intermediate loop 334 of the first part 306 of the inductor 400 and a second end connected to a first end of the inner loop 440 of the first part 306. Compared to the inductor 300, the third conductive link 330 of [Fig.3] now has its second end connected to a second end of the inner loop 440 of the first part 306.

[0076] As in [Fig. 3], the inductive loops of the first part 306 and the second part 308 of the inductor 400 are arranged so that a current flows in them with opposite rotations, in other words the current flows in the direction of clockwise in the loops of one part and counterclockwise in the loops of the other part. For example, when a current flows from terminal 302 to terminal 304 of the inductor 400, in a direction indicated by arrows in [Fig.4], the current flows clockwise in the outer loop 310, the intermediate loop 334 and the inner loop 340 of the first part 306 and the current flows counterclockwise in the outer loop 318, the intermediate loop 326 and the inner loop 420 of the second part 308.Similarly, when a current flows in the opposite direction to the arrows, i.e. from terminal 304 to terminal 302 of the inductor, the current flows counterclockwise in the outer loop 310, the intermediate loop 334 and the inner loop 440 of the first part 306 and clockwise in the outer loop 318, the intermediate loop 326 and the inner loop 420 of the second part 308.

[0077] By using the structure of [Fig. 3] or [Fig. 4], it is possible to increase the number of loops of the inductor 100 of [Fig. 1] by increasing the number of inner loops in each part, without increasing the number of crossing points. The inductor has a conductive link in the second conductive layer, which connects one end of the innermost loop of the first part 306 of the inductor to one end of the innermost loop of the second part 308 of the inductor.

[0078] Therefore, it is possible to increase the inductance value of inductor 100 without degrading its quality factor. Increasing the number of loops increases the inductance value without increasing the inductance area.

[0079] Although examples have been described in connection with Figures 3 and 4 in which the figure-eight shaped inductor 300, 400 comprises 4 or 6 loops, in alternative embodiments, the same structural principle of Figures 3 and 4 can be applied to inductors that have a different number of loops, for example, more than 6 loops. In some embodiments, the number of loops in the inductor is the same as the identical number of loops in each part of the inductor. The loops in each part are, for example, concentric. The width of the loops in each part decreases, for example, with each loop, as one moves from the outermost loop to the innermost loop.

[0080] Although the terminals 302, 304 of the inductor 300 of [Fig. 3] and the inductor 400 of [Fig. 4] are positioned so that the lengths of the partial outer loops 310a and 310b are similar, thus forming half-loops, in other embodiments the lengths of the partial outer loops 310a and 310b are different from each other, and the sum of the lengths of the partial outer loops 310a and 310b remains the same, for example.

[0081] In some embodiments, the inductor 300, 400 has symmetry, except with regard to the presence of terminals 302, 304 in a part, by rotating 180° around the center of symmetry C of the inductor 300, 400. The center of symmetry C of the inductor 300, 400 corresponds for example to the position of the crossing point between the connecting links 314 and 330.

[0082] Fig. 5 is a graph illustrating an example of the inductance value L, in nanohenrys (“L [nH]”) of inductor 200 of Fig. 2, 520, and of inductor 200 of Fig. 3, 530, as a function of the frequency of an alternating current F in gigahertz (“F [GHz]”) flowing through them.

[0083] For an alternating current frequency of 4.88 GHz, the inductances of inductors 200 and 300 are similar: 1.22 nH for inductor 200 and 1.20 nH for inductor 300.

[0084] The self-resonance frequency (SRF) is the upper limit of the operating frequency of an inductor. The SRF is higher for inductor 300 than for inductor 200, so that inductor 300 has a wider operating frequency range and therefore a wider range of inductance values.

[0085] Fig. 6 is a graph illustrating an example of the quality factor Q of inductor 200 of Fig. 2, 620, and of inductor 300 of Fig. 3, 630, as a function of the frequency of an alternating current F in gigahertz (“F [GHz]”) flowing through them.

[0086] The quality factor of inductor 300 is superior to the quality factor of inductor 200 over the entire dynamic range.

[0087] At 4.88 GHz, the quality factor of inductor 200 is 17.74 and the quality factor of inductor 300 is 21.34. At this frequency of 4.88 GHz, [Fig. 5] shows that the inductance values ​​of inductors 200 and 300 are similar, and [Fig. 6] shows that the quality factor of inductor 300 is 20% higher than the quality factor of inductor 200. This corresponds to a 20% reduction in energy consumption.

[0088] Fig. 7 schematically represents an emitter 700 in which the figure-eight inductor 300 of Fig. 3 or the figure-eight inductor 400 of Fig. 4 can be incorporated according to one example of an embodiment of the present description.

[0089] The transmitter 700 includes, for example, an intermediate frequency amplifier ("IF AMP") 710 receiving a first signal INI and configured to generate an amplified signal INI' by amplifying a frequency range of the first signal IN10. A mixer 720 is connected to the output of the intermediate frequency amplifier 710 and receives the signal INI' at a first input and receives a second signal IN2 at a second input. The second signal IN2 is, for example generated by a voltage-controlled oscillator (VCO) 730, which is configured to receive a control voltage (not shown) and to generate the second signal IN2 at a frequency controlled by the control voltage. The VCO 730 includes an inductor, for example, inductor 300 of [Fig. 3] or inductor 400 of [Fig. 4]. The mixer 720 is configured to generate an output signal OUT, which is a combination of the first signal INI' and the second signal IN2. A power amplifier (PPA) 740 is, for example, connected to the output of the mixer 720 and is configured to amplify the output signal OUT. The power amplifier 740 includes, for example, a balun 750.

[0090] A magnetic field generated by the inductor of the VCO 730 can induce unwanted coupling with the symmetrizer 750. Using the figure-eight shaped inductor 300 or 400 to implement the inductor of the VCO 730 leads to relatively low induced inductive coupling while maintaining a relatively high quality factor.

[0091] Fig. 8 schematically represents another emitter 800 in which the figure-eight shaped inductor 300, 400 of Fig. 3 or Fig. 4 can be incorporated according to another embodiment of the present description.

[0092] The transmitter 800 includes, for example, a phase-locked loop (PLL) 805. The PLL includes, for example, a mixer 810, a phase-frequency divider (PFD) 820, a loop filter (FILTER) 830, a voltage-controlled oscillator (VCO) 840, a buffer 850, and a divider (DIV) 860. The operation of a PLL is known to a person skilled in the art and will not be described in detail. The PLL is, for example, connected to an input of a power amplifier (PA) 870. The power amplifier is, for example, configured to amplify an output signal from the PLL and to transmit the amplified signal to an antenna 880.

[0093] The PLL's VCO 840 includes an inductor. A magnetic field generated by this VCO inductor can induce unwanted coupling with the 880 antenna. Using the figure-eight shaped inductor 300, 400 to implement this inductor leads to relatively low induced inductive coupling while maintaining a relatively high quality factor.

[0094] Fig.9 schematically represents an integrated circuit 900 comprising the figure-eight inductor 300 of Fig.3 or the figure-eight inductor 400 of Fig.4 according to one example of an embodiment of the present description.

[0095] The integrated circuit 900 includes an electronic circuit 910 which is connected, by means of a first terminal 915 of the circuit 910, to the first terminal 302, 402 of the inductor 300, 400 and is configured to apply a current to the first terminal 302, 402. The inductor 300, 400 is configured to supply the current at the second terminal 304, 404 which is connected to a second terminal 920 of the electronic circuit 910.

[0096] Fig. 10 represents a structure of the first conductive layer of the figure-eight inductor of Fig. 300 according to an example of an embodiment of the present description.

[0097] Some elements of [Fig. 10] are similar to elements of [Fig. 3]. They are referenced with the same references and will not be detailed again.

[0098] According to an example of an embodiment shown in [Fig. 10], the inductor 300 has loops of octagonal shape. In other embodiments, the loops have other shapes, for example circular, square, hexagonal, etc.

[0099] The second conductive layer, comprising the conductive link 330 of the inductor 300 of [Fig. 3], is not shown in [Fig. 10]. A first via 1010 connected to the second end of the inner loop 326 of the second part 308 is configured to connect the first and second conductive layers. The via 1010 is also connected to the first end of the conductive link 330, not shown in [Fig. 10]. A second via 1020 connected to the first end of the inner loop 334 is configured to connect the first and second conductive layers. The via 1020 is also connected to the second end of the conductive link 330, not shown in [Fig. 10].

[0100] An example of a process for manufacturing the figure-eight inductor 300 in a stack of insulating and conductive layers comprises the following steps. A similar manufacturing process could be used to form the figure-eight inductor 400 of [Fig. 4].

[0101] According to one embodiment, the method comprises forming, in the first conductive layer of the stack: terminals 302, 304; loops 310a, 318, 326, 334, 310b; conductive links 338, 322 that connect two loops of the first part 306 or two loops of the second part 308; and the conductive link that connects the outer loop 318 of the second part 308 to the partial outer loop 310a of the first part 306. The method then comprises, for example, forming: the first via 1010 that is in contact with the second end of the inner loop 326 of the second part 308; and the second via 1020 which is in contact with the first end of the inner loop 334. The process then includes, for example, the formation in the second conductive layer of the stack of the third conductive bond which connects the first via 1010 and the second via 1020.

[0102] According to another embodiment, the process includes the formation, in the second conductive layer of the stack, of the third conductive bond 330. The process then includes, for example, the formation of: the first via 1010 which contacts the first end of the third conductive bond 330; and the second via 1020 which contacts the second end of the third conductive bond 330. The process then includes, for example, the formation in the first conductive layer of the stack of: the inner loop 326 of the second part 308 which has its second end which contacts the first via 1010; the inner loop 334 of the second part 308 which has its first end which contacts the second via 1020; terminals 302, 304; loops 310a, 318, 310b; conductive links 338, 322 which connect two loops of the first part 306 or two loops of the second part 308; and the conductive link which connects the outer loop 318 of the second part 308 with the partial outer loop 310a of the first part 306.

[0103] The advantages of the embodiments described include a reduced number of crossover points while maintaining a figure-eight shaped inductor: inductor 300 of [Fig. 3] and inductor 400 of [Fig. 4] have only one crossover point. Maintaining a low number of crossover points results in relatively low resistance and capacitance and a relatively high quality factor of the inductor. The inductor's energy consumption is also relatively low.

[0104] Thanks to the small number of crossing points, a relatively high number of loops can be designed and used for figure-eight inductors while maintaining a good quality factor. This makes it possible to obtain a relatively high inductance value and a relatively low surface area value.

[0105] The self-resonance frequency is also improved, which expands the dynamic range of the inductor.

[0106] The inductor as described herein has, for example, numerous applications in different industries. For example, the inductor 300, 400 is incorporated into a device with one or more other components.

[0107] The device is intended, for example, for the automotive industry. The electrification of motor vehicles generates a high and increasing level of electronic content in vehicles. The device includes, for example, thyristors, rectifiers, high-voltage transient suppression diodes, modules, etc., for incorporation into said vehicles. Automated driving also generates a high and increasing level of electronic content in vehicles. The device includes, for example, high-voltage transient suppression diodes, protection against electromagnetic discharge, and common-mode filters for protection against electrical hazards in the latest complex electronic circuits.

[0108] The device can, for example, be used in the industrial sector. More specifically, the device is intended, for example, to be used for developing green energy or for the electrification of infrastructure, for example for charging stations or for incorporating solar energy. The device can also be used in the Internet of Things and smart homes. For example, the device is intended for use in power supply and energy circuits for equipment components, including 800 V or 1200 V thyristors, 1200 V silicon carbide and ultrafast diodes, transient voltage suppression diodes, and electromagnetic discharge protection. The device can also be used in the implementation of cloud computing, 5G networks, data centers, and servers. The device incorporates, for example, wide bandgap materials.

[0109] The device is intended, for example, for use in personal electronic circuits, for example, to increase radio frequency content, in a 5G connection device, or more generally in connected devices. The device is, for example, a smartphone or part of an Internet of Things network. The device is, for example, connected via 5G, Wi-Fi, or ultra-wideband. The device includes, for example, high-speed interfaces, for example, with advanced filtering and protection against electromagnetic discharge.

[0110] The device is intended, for example, for use in communication equipment or in computers or peripherals. For example, the device can be used in 5G infrastructures and dedicated data centers. The device includes, for example, silicon carbide diodes, power Schottky transistors, electromagnetic discharge protection, and transient voltage suppression diodes. The device can also be used in satellites, including, for example, passive integrated devices for radio frequency applications.

[0111] Various embodiments and variations have been described. Those skilled in the art will understand that certain features of these various embodiments and variations could be combined, and other variations will become apparent to them. In particular, the embodiments can be extended to inductors having a different number of loops and / or a different shape for the loops, for example, circular, square, etc.

[0112] Finally, the practical implementation of the embodiments and variants described is within the reach of a person skilled in the art, based on the functional indications given above.

Claims

Demands

1. Figure-eight shaped inductor (300, 400), comprising: in a first conducting layer of a stack of insulating and conducting layers: - an outer loop (318) of a first part (308) of the inductor having a first end connected to an end of a first outer partial loop (310a) of a second part (308) of the inductor and a second end connected to a first end of one or more inner loops (326, 420) of the first part of the inductor, the outer loop and the one or more inner loops of the first part being concentric;and - one or more inner loops (334, 440) of the second part of the inductor having a first end connected to one end of a second outer partial loop (310b) of the second part of the inductor, the first and second outer partial loops and the one or more inner loops of the second part of the inductor being concentric; the inductor further comprising a conductive link (330) which connects a second end of the one or more inner loops of the first part of the inductor to a second end of the one or more inner loops of the second part of the inductor, the conductive link being partially in a second conductive layer.

2. Inductor according to claim 1, wherein a current applied between a first terminal (302) and a second terminal (304) of the inductor flows in a first direction of rotation in the outer loop (318) and in one or more inner loops (326, 420) of the first part (308) and in a second direction of rotation opposite to the first direction in the first and second outer partial loops (310a, 310b) and in one or more inner loops (334, 440) of the second part (306).

3. An inductor according to any one of claims 1 or 2, wherein, in the first part (308), a first width (W1) of the outer loop is greater than a second width (W2) of one or more inner loops, and wherein, in the second part (306), a third width (W1) of the first

4.

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9. and the second outer partial loop is larger than a fourth width (W2) of one or more inner loops. Inductor according to any one of claims 1 to 3, wherein the second conductive layer is closer to the substrate than the first conductive layer. Inductor according to any one of claims 1 to 3, wherein the first conductive layer is closer to the substrate than the second conductive layer. Integrated circuit (900) comprising at least one inductor (300, 400) according to any one of claims 1 to 5. Voltage-controlled oscillator comprising at least one inductor according to any one of claims 1 to 5. Transmitter (700, 800) comprising at least one inductor (300, 400) according to any one of claims 1 to 5. A method comprising: - the application of a current, by an electronic circuit (910), to an inductor (300, 400) in the shape of a figure eight, comprising: in a first conductive layer of a stack of insulating and conductive layers: an outer loop (318) of a first part (308) of the inductor having a first end connected to one end of a first outer partial loop (310a) of a second part (308) of the inductor and a second end connected to a first end of one or more inner loops (326, 420) of the first part of the inductor, the outer loop and the one or more inner loops of the first part being concentric; and one or more inner loops (334, 440) of the second part of the inductor having a first end connected to one end of a second outer partial loop (310b) of the second part of the inductor, the first and second outer partial loops and the one or more inner loops of the second part being concentric; the inductor further comprising a conductive link (330) which connects a second end of one or more inner loops (326, 420) of the first part of the inductor to a second end of one or more inner loops (334, 440) of the second part of the inductor, the conductive bond being partially in a second conductive layer; - the transmission of current in the inductor.

10. A method according to claim 9, wherein: - current is applied to a first terminal (302) of the inductor (300, 400); - current is transmitted from the first terminal (302) to a second terminal (304) of the inductor; and - current is supplied to the second terminal (304) of the inductor.

11. Method of manufacturing a figure-eight shaped inductor (300, 400), the method comprising: in a stack of insulating and conductive layers: - the formation, in a first conductive layer of the stack, of an outer loop (318) of a first part (308) of the inductor having a first end connected to an end of a first outer partial loop (310a) of a second part (306) of the inductor and a second end connected to a first end of one or more inner loops (326, 420) of the first part of the inductor, the outer loop and the one or more inner loops of the first part being concentric;- the formation, in the first conductive layer of the stack, of one or more inner loops (334, 440) of the second part of the inductor having a first end connected to one end of a second outer partial loop (310b) of the second part of the inductor, the first and second outer partial loops and the one or more inner loops of the second part of the inductor being concentric.;

12. A method for manufacturing a figure-eight shaped inductor (300, 400) according to claim 11, the method further comprising, after formation in the first conductive layer: - the formation of a first via (1010) which contacts a second end of one or more inner loops (326, 420) of the first part (308) of the inductor; - the formation of a second via (1020) which contacts a second end of one or more inner loops (334, 440) of the second part (306) of the inductor; and - the formation, in a second conductive layer of the stack, of a conductive bond (330) which connects the first via (1010) and the second via (1020).

13. A method for manufacturing a figure-eight shaped inductor (300, 400) according to claim 11, the method further comprising, before the formation of the first conductive layer: - the formation, in a second conductive layer of the stack, of a conductive bond (330); - the formation of a first via (1010), which comes into contact with a first end of the conductive bond (330) and which also comes into contact with a second end of one or more inner loops (326, 420) of the first part (308) of the inductor; and - the formation of a second via (1020), which comes into contact with a second end of the conductive bond (330) and which also comes into contact with a second end of one or more inner loops (334, 440) of the second part (306) of the inductor.

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