Photonic device comprising a laser source and means for managing heat dissipation

Description

DOMAINE DE L'INVENTION

[0001] The present invention relates to the fields of microelectronics, optics, electro-optics, and photonics. In particular, the invention relates to a photonic device comprising at least one III-V semiconductor laser source integrated into a silicon substrate and equipped with heat dissipation means whose arrangement allows for more efficient heat dissipation compared to arrangements known to those skilled in the art.

[0002] The present invention proposes a device for supplying power to one or more lasers integrated on a support, for example silicon, while improving the heat dissipation of the lasers to a heat dissipation plate. ARRIERE PLAN TECHNOLOGIQUE DE L'INVENTION

[0003] Document [1] cited at the end of the description discloses a heterogeneous laser device 1. This device 1, as illustrated in [ Fig.1 ], comprises, from a rear face 1B to a front face 1A, a support substrate 2, notably made of silicon, on a main face 3 of which rests a photonic layer 4.

[0004] Specifically, the photonic layer 4 comprises at least one layer of dielectric material in which a waveguide 5 and a photonic stack 6 formed from a plurality of III-V semiconductor material layers structured into a second waveguide are encapsulated. More particularly, the photonic stack 6 and the waveguide 5 are optically coupled to form a heterogeneous laser source.

[0005] More specifically, photonic layer 4, as represented in the [ Fig.1 ], comprises, from the main face 3, a stack of three layers, called, respectively, first layer 7, second layer 8 and third layer 9. In this respect, the waveguide 5 can be arranged in the first layer 7 and flush with the interface formed between the first layer 7 and the second layer 8, while the photon stack 6, vertically above the waveguide 5, can be arranged in the third layer 9 and flush with the interface formed between the second layer 8 and the third layer 9.

[0006] Furthermore, device 1 shown in the [ Fig.1 ] also includes interconnection means provided with contact pads 10A and 10B accessible from the front face 1A and electrically connected to the photon stack 6 by means of connection vias 10A and 10B which extend into the photon layer 4 and more particularly into the third layer 9.

[0007] Thus, as soon as a voltage is applied to each of the contact pads, the photon stack is capable of emitting laser radiation. This laser radiation is guided in the waveguide 5 and the photon stack 6, and can, depending on the configuration of device 1, be injected into an optical fiber or another photonic device via coupling means formed in device 1.

[0008] Also, in order to ensure optimal confinement of the laser radiation in the waveguide, and consequently limit optical losses, the photonic layer is generally formed of dielectric layers 7, 9 of relatively large thicknesses, for example on the order of 800 nm, or even greater.

[0009] However, during operation, the photon stack 6 undergoes heating which, if not controlled, is likely to affect the performance of device 1 and, more specifically, the laser source. The dielectric layers forming the photon layer thus constitute an obstacle to heat dissipation and, consequently, exacerbate this heating.

[0010] Document [2] cited at the end of the description also proposes a heterogeneous laser device. In particular, this laser device comprises (according to the [ Fig.9 [2]) a silicon substrate on one face of which rest, in order, a layer of silicon dioxide, a layer of silicon, and a photon stack. The photon stack, like that proposed in [1], is formed of a plurality of layers of III-V semiconductor materials structured into a waveguide, called a laser guide. The laser guide is coupled in this respect to a waveguide formed in the silicon layer. This device also includes thermal dissipation means configured to dissipate the heat that may be produced by the photon stack. More specifically, these means include polycrystalline silicon bridges formed above the photon stack and configured to dissipate the heat produced by the photon stack to the silicon substrate.

[0011] Document [3] cited at the end of the description proposes an alternative architecture for controlling heat dissipation. More specifically, and as illustrated in [ Fig.4 ](j) of document [3], the heterogeneous laser device includes thermal bridges made of metal, and thermally connecting the silicon substrate with the contact pads of the photon stack.

[0012] Finally, document [4], cited at the end of the description, also discloses a photonic device equipped with heat dissipation means configured to dissipate the heat produced by a photonic stack. Specifically, the photonic stack is formed from a plurality of layers of III-V semiconductor materials structured into a waveguide, referred to as a laser guide. The laser guide is coupled to a waveguide formed directly above it. In the proposed architecture, the heat dissipation means comprise metallic layers encapsulated in a dielectric layer resting on one face of a support substrate, enabling the heat produced by the photonic stack to be dissipated to the support substrate.

[0013] Nevertheless, the effectiveness of the solutions proposed in these documents remains limited.

[0014] Therefore, one aim of the present invention is to propose a heterogeneous laser device provided with means of thermal dissipation whose efficiency is improved compared to known solutions in the prior art. BREVE DESCRIPTION DE L'INVENTION

[0015] The invention relates to a photonic device comprising a photonic chip and a support substrate, the photonic chip comprising a support layer and a photonic layer resting by its lower face on a principal face of the support layer, said photonic layer, which comprises at least one dielectric material, encapsulates at least one laser source formed by a waveguide and a photonic stack optically coupled to each other, the photonic stack being made of III-V semiconductor materials, the photonic chip also comprising a first and a second metallic pad having, respectively, a first and a second surface, accessible by an upper face of the photonic layer opposite the lower face, and electrically connected to the photonic stack by means of connecting vias which extend into the photonic layer,The first and second pads are configured to allow the flow of an electric current in the photonic stack in order to control the emission of laser radiation by the laser source; the photonic device further comprises: of the first thermal dissipation means configured to dissipate the heat likely to be emitted by the laser source, the first means include a transfer layer and a transfer element in thermal contact with the transfer layer, the transfer layer includes an electrically insulating material which is at least partially overlapping at least one of the first and second surfaces; of the connection means configured to electrically connect the first pad and the second pad with a first terminal and a second terminal disposed on either of the support substrate and the transfer layer.

[0016] According to one implementation method, the transfer layer is in contact with the first pad and the second pad.

[0017] According to one implementation method, the transfer layer is made of a material, called the transfer material, which has a thermal conductivity greater than or equal to 20 W / m / K, the transfer layer advantageously comprising at least one of the materials chosen from: a polymer material, AlN or silicon.

[0018] Depending on one implementation method, the waveguide is made of silicon, or silicon nitride, or a hybrid form of silicon nitride and silicon.

[0019] According to one embodiment, said photonic device also includes second means configured to dissipate heat that may be emitted by the laser source towards the support; the second means include second vias extending, in the direction of the main face, from the waveguide.

[0020] According to one embodiment, the second means also include a metallic insert, generally flat in shape and interposed between the second vias and the main face; the second means further include terminal second vias extending from the metallic insert to the main face; an additional insert is advantageously interposed between the main face and the terminal second vias.

[0021] According to one embodiment, said photonic device also includes third means configured to dissipate heat that may be emitted by the laser source; the third means include third vias extending, in the direction of the main face, from, respectively, the first pad and the second pad.

[0022] According to one embodiment, the third means also include two metallic inserts called, respectively, first insert and second insert, generally planar in shape, the first insert interposed between the main face and the third via extending from the first pad, the second insert interposed between the main face and the third via extending from the second pad, the third means further include at least one terminal third via extending from the first insert to the main face, and at least one other terminal third via extending from the second insert to the main face.

[0023] According to one implementation method, the support face is assembled with a face of the support layer, called the secondary face, opposite the main face of said support layer.

[0024] According to one embodiment, the transfer layer partially covers one of the first and second surfaces, leaving a first section and a second section, respectively, of the first and second surfaces free of access, a first wire directly connects the first terminal and the first pad, while a second wire directly connects the second terminal and the second pad, the first and second terminals being arranged on the support substrate.

[0025] According to one embodiment, the transfer layer comprises two secondary metal pads, respectively called the first secondary pad and the second secondary pad, accessible by a contact face of the transfer layer opposite the top face, a first metal ball connecting the first secondary pad and the first pad, and a second metal ball connecting the second secondary pad and the second pad, the first terminal and the second terminal are arranged on the contact face, the first terminal and the first secondary pad are connected via a first redistribution line, while the second terminal and the second secondary pad are connected via a second redistribution line.

[0026] According to one embodiment, the support face is assembled to the photonic layer by the top face by means of metal balls also ensuring the electrical connection of the first and second pads with, respectively, the first terminal and the second terminal, the support substrate comprising a through opening through the support substrate from the support face to a face of the support substrate opposite to the support face, said through opening being configured to allow the positioning of the first means.

[0027] According to one embodiment, said photonic device includes coupling means configured to inject laser radiation emitted by the laser source into an optical fiber or an optical fiber network.

[0028] According to one embodiment, the coupling means are configured to allow coupling by a slice, called the coupling slice, of said device perpendicular to the main face, advantageously the coupling means include a lens associated with the coupling slice.

[0029] According to one embodiment, the coupling means include a diffraction grating disposed in the photonic layer and configured to permit optical coupling by the top face of the laser radiation emitted by the laser source and an optical fiber or an optical fiber array. Brève description des dessins

[0030] Other features and advantages of the invention will become apparent from the detailed description that follows, with reference to the accompanying figures in which: [ Fig.1 ] There [ Fig.1 ] is a schematic representation of a photonic device equipped with a source made of III-V semiconductor material known from the prior art; [ Fig.2A ] There [ Fig.2A ] is a schematic representation of a photonic device according to a first embodiment of the present invention, in which only the first means are shown; the photonic device is notably represented along a cross-sectional plane perpendicular to the main face; [ Fig.2B ] There [ Fig.2B ] is a schematic representation of a photonic device according to a first embodiment of the present invention, and in which the first, second and third means are represented, the photonic device is in particular represented according to a cutting plane perpendicular to the main face; [ Fig.3 ] There [ Fig.3 ] is a schematic representation of an example of a photonic device conforming to the embodiment shown in the [ Fig.1 ], there [ Fig.3 ] is notably simplified for reasons of clarity; in particular, in this example, the photonic layer is formed by a stacking of a first layer, a second layer, and a third layer; the photonic device is notably represented according to a cross-sectional plane perpendicular to the main face; [ Fig.4 ] There [ Fig.4 ] is a schematic representation of a photon stack that can be implemented in a photonic device according to the present invention; for clarity, the photon stack is shown isolated from said photonic device and along a cross-sectional plane perpendicular to the main face; Fig.5 ] There [ Fig.5 ] is a schematic representation of a waveguide that can be implemented in a photonic device according to the present invention; for clarity, the waveguide is shown isolated from said photonic device and in a cross-sectional plane perpendicular to the main face; Fig.6 ] There [ Fig.6 ] is a simplified representation of the device of the [ Fig.1 detailing the arrangement of the second means; Fig.7 ] There [ Fig.7 ] is a simplified representation of the device of the [ Fig.1 detailing the arrangement of the third means; Fig.8 ] There [ Fig.8 ] is a schematic and simplified representation of a photonic device equipped with coupling means; according to a second example, the photonic device is notably represented along a cross-sectional plane perpendicular to the main face; [ Fig.9 ] There [ Fig.9 ] is a schematic and simplified representation of a photonic device equipped with coupling means. According to a first example, the photonic device is notably represented along a cross-sectional plane perpendicular to the main face; [ Fig. 10 ] There [ Fig.10 ] is a front-facing view of a photonic device equipped with a plurality of laser sources and a first means common to all laser sources; [ Fig.11 ] There [ Fig.11 ] represents a photonic device according to the present invention and comprising a driver chip; [ Fig.12 ] There [ Fig.12 ] is a schematic representation of a photonic device according to a second embodiment of the present invention, the photonic device is in particular represented according to a cutting plane perpendicular to the main face; [ Fig.13 ] There [ Fig.13 ] is a schematic representation of a photonic device according to a third embodiment of the present invention, the photonic device is in particular represented according to a cutting plane perpendicular to the main face. DESCRIPTION DETAILLEE DE L'INVENTION

[0031] The present invention relates to a photonic device and more particularly to a photonic device which includes a photonic chip provided with a heterogeneous laser source and thermal dissipation means configured to dissipate the heat likely to be emitted by the laser source.

[0032] More specifically, the present invention relates to a photonic device comprising a photonic chip and a support substrate, the photonic chip comprising a support layer and a photonic layer. In particular, the photonic layer rests, on its lower face, on a principal face of the support layer. Furthermore, the photonic layer, which comprises at least one dielectric material, encapsulates a laser source formed by a waveguide and a photonic stack optically coupled to each other.

[0033] The photonic chip also includes a first pad and a second pad, each having a first and second surface, respectively, accessible from an upper face of the photonic layer opposite the lower layer. In this respect, the first and second pads are electrically connected to the photonic stack by means of connecting vias that extend into the photonic layer.

[0034] In addition, the heat dissipation means include first means configured to dissipate heat that may be emitted by the laser source.

[0035] More specifically, the first means comprise a transfer layer and a transfer element exclusively in contact with the transfer layer. The transfer layer includes, in particular, an electrically insulating material that partially covers at least one of the first and second surfaces, leaving a first and second section, respectively, of the first and second surfaces free to access.

[0036] This particular arrangement of the transfer layer thus makes it possible to electrically connect, with connecting means, the first and second sections with the metallic tracks of the support substrate at the level of a support face of said substrate.

[0037] The means of heat dissipation may also include second and third means configured to dissipate heat that may be emitted by the laser source.

[0038] The second and third means comprise, respectively, second and third vias extending, in the direction of the main face, from, respectively, the waveguide, and from one and / or the other of the first and second pad.

[0039] To the [ Fig.2A [ ], a photonic device 100 can be seen according to a first embodiment of the present invention. The photonic device 100 comprises a photonic chip 101 which includes, from a rear face 100B to a front face 100A, a support layer 200 and a photonic layer 300. The photonic device 100 also includes a support substrate 210 having two parallel faces, respectively called the support face 210A and the free face 210B. More particularly, the support substrate 210 includes, on its support face 210A, a first terminal 211 and a second terminal 212. More particularly, the first terminal 211 and the second terminal 212 are configured to allow the control and / or interfacing of the photonic device 100 with control means.In this respect, the first terminal 211 and the second terminal 212, accessible from the support face, extend along the thickness of the support substrate 210 by means of, respectively, a first via 211A and a second via 212A. The first via 211A and the second via 212B are arranged to allow an electrical connection via the free face 210B. For example, a pad 211B and a pad 212B can be arranged on the free face 210B, extending, respectively, from the first via 211B and the second via 212B.

[0040] The support layer 200 comprises two faces, parallel to each other, called, respectively, the main face 200A and the secondary face 200B, while the photonic layer 300 also comprises two faces parallel to the main face 200A and called, respectively, the lower face 300A and the upper face 300B. In this regard, and as illustrated in the [ Fig.2A ], the photonic layer 300 rests on the main face 200A by its lower face 300A, while the support layer rests on the support face 210A by its secondary face 200B.

[0041] The support layer 200 may comprise a semiconductor material, and more particularly a single-crystal semiconductor material. In this regard, the support layer 200 may advantageously comprise single-crystal silicon. This latter material is known to be compatible with microelectronic and / or photonic component manufacturing lines and exhibits a high thermal dissipation coefficient, the advantage of which will be discussed later in the description of the present invention.

[0042] The photonic layer 300 comprises at least one layer of dielectric material in which a waveguide 400 and a photonic stack 500 are encapsulated. More specifically, the photonic stack 500 comprises a plurality of layers of III-V semiconductor materials and is optically coupled to the waveguide 400 to form a heterogeneous laser source. More specifically, the photonic stack 500 may comprise a plurality of layers of III-V semiconductor materials structured into a second waveguide that is optically coupled to the waveguide 400.

[0043] In other words, laser radiation that can be emitted by the photon stack 500 will be coupled to the waveguide 400 and guided by the latter.

[0044] Thus, and by way of example and as illustrated in the [ Fig.4 ] (there [ Fig.4 (representing the photon stack isolated from the rest of the photonic device), the photon stack 500 may comprise, from the front face 100A to the back face 100B, a top layer 501, one or more quantum well layers 502, and a bottom layer 503. Notably, the top layer 501 may comprise a P-doped III-V semiconductor material, while the bottom layer 503 may comprise an N-doped III-V semiconductor material. More specifically, the top layer 501 and the bottom layer 503 may comprise P-doped and N-doped InP, respectively. The quantum well layer(s) 502 may comprise one or more III-V semiconductor materials, for example, InP-based materials.

[0045] Furthermore, the 500 photon stack is advantageously positioned directly above the 400 waveguide. As for the 400 waveguide, as illustrated in the [ Fig.5 ] (there [ Fig.5 representing the waveguide isolated from the rest of the photonic device), it may comprise a central rib 401 and a base 402 resting on said central rib 401 so as to present a "T"-shaped profile along a cutting plane perpendicular to the first face. This latter aspect is not intended to limit the scope of the present invention to this single geometry, and those skilled in the art may design a waveguide with a different profile. For example, it may be possible to consider a waveguide with a square or even rectangular cross-section.

[0046] It is also understood that the material forming the waveguide 400 has a higher refractive index than the dielectric material forming the photonic layer 300.

[0047] The photonic chip 101 also includes two contact pads, referred to as the first pad 601 and the second pad 602. More specifically, the first pad 601 and the second pad 602 have, respectively, a first surface 601A and a second surface 602A, accessible from the upper face 300B of the photonic layer 300. In particular, the first pad 601 and the second pad 602 are electrically connected to the photonic stack 500 by means of connecting vias 603, 604 which extend into the photonic layer 300.

[0048] As an example, the contact pads may include aluminum and have a thickness of around 3 µm.

[0049] By "accessible from the top face," we mean a contact pad that presents a surface (the first surface and the second surface) flush or projecting with the top face. It is further understood, without needing to be explicitly stated, that the first and second surfaces are parallel, or at least essentially parallel, to the main face 200A. It follows from this last point that the first and second surfaces are parallel to each other.

[0050] The first pad 601 can be connected to the upper layer 501 of the photon stack 500 by means of a connection via called first contact via 603, while the second pad 602 can be connected to the lower layer 503 of the photon stack 500 by means of another connection via called second contact via 604.

[0051] It is understood that the contact pads 601, 602 and the connecting vias 603, 604 comprise an electrically conductive material, more particularly a metal, for example aluminium and / or copper.

[0052] The contact pads 601 and 602, as well as the connecting vias 603 and 604, as previously described, allow the flow of current within the photon stack 500, and consequently, the emission of laser radiation from the latter. The emitted laser radiation is then coupled and guided by the waveguide 400.

[0053] It is known that the laser source formed by the 400 waveguide and the 500 photon stack is susceptible to heating during operation. This heating can impair the operation of the laser source and ultimately degrade its performance.

[0054] Thus, the present invention also implements first 700 means of heat dissipation configured to dissipate heat that may be emitted by the laser source ([ Fig.2A ]).

[0055] Advantageously, the present invention can also implement second means 720 and third means 740 of heat dissipation configured to dissipate heat that may be emitted by the laser source ([ Fig.2B ]).

[0056] In this regard, the first means 700 include a thermal transfer layer 701 and a thermal transfer element 702.

[0057] According to this first embodiment, the transfer layer 701 comprises an electrically insulating material which is partially overlapping at least one of the first surface 601A and the second surface 602A, leaving a first section 601B and a second section 602B, respectively, of the first surface 601A and the second surface 602A free access.

[0058] It is therefore understood that when the transfer layer 701 is in contact with a contact pad, it is in overlap of the first and / or second surface of the pad in question, and this overlap is only partial so as to allow a re-establishment of contact at the level of the first section 601B and the second section 602B, for example by means of a welded wire.

[0059] In particular, the photonic device 100 also includes connecting wires called, respectively, first wire 605 and second wire 606. More specifically, the first wire 605 directly connects the first section 601B with the first terminal 211, while the second wire 606 directly connects the second section 602B with the second terminal 212.

[0060] Advantageously, the transfer layer is made of a material, called the transfer material, which has a thermal conductivity greater than or equal to 20 W / m / K, for example a transfer layer with a thickness of 150 µm with a thermal conductivity of 130 W / m / K may be considered.

[0061] In particular, the transfer material may include a dielectric material sold by the company T-global ™< sold under the reference Thermal Tape.

[0062] The choice of transfer material is accessible to a person skilled in the art.

[0063] The transfer material also exhibits an electrical resistivity greater than 10< 12< Ohm.cm.

[0064] For example, the thickness of the transfer layer can be 0.15 µm. However, a person skilled in the art can adjust the thickness of the transfer layer according to the resistivity of the material in question.

[0065] The heat transfer element 702 is advantageously exclusively in contact with the heat transfer layer 701. In other words, the heat transfer element 702 is electrically isolated from both the first pad 601 and the second pad 602.

[0066] The heat transfer element may include at least one of the following elements: a metal plate, a thermoelectric cooling plate, an air-cooled radiator, a plate with cooling channels (for example, channels allowing the circulation of a fluid, in particular water).

[0067] The invention is not limited to these elements alone, and a person skilled in the art may implement any other type of cooling element that might be suitable.

[0068] Advantageously, the 702 transfer element can be configured to be thermalizable.

[0069] By "thermalisable", we mean a heat transfer element capable of having a given temperature imposed upon it.

[0070] According to an example illustrated in the [ Fig.3 ], the photonic layer 300 comprises, from the main face 200A, a first layer 301, a second layer 302 and a third layer 303. More particularly, and still according to this example, the waveguide 400 is arranged in the first layer and flush with the interface, called first interface 301A, formed between the first layer 301 and the second layer 302, while the photonic stack 500 is arranged in the third layer 303 and flush with the interface, called second interface 303A, formed between the second layer 302 and the third layer 303.

[0071] It is also worth noting that the second layer 302 is optional.

[0072] Thus, as soon as the laser source is in operation, the heat emitted by the latter is drained through the connection vias 603, 604 and the contact pads to the first means 700 of thermal dissipation and in particular to the dissipation plate 702. The consideration of a thermal transfer layer made of an electrically insulating material allows us to consider a dissipation of heat by cooperation with both of the first pad and the second pad.

[0073] Thus, the first means, as considered in the present invention, make it possible to limit the heating of the laser source when it is in operation. More specifically, when only the first means are implemented, the inventors were able to observe a temperature difference between the laser source and the heat dissipation plate of less than 10°C, whereas without the implementation of the first means, a temperature difference between the support substrate 200 and the laser source of between 20°C and 30°C would be observed. Limiting and / or controlling the heating of the laser source according to the principles of the present invention makes it possible to improve the stability of said laser source.

[0074] As illustrated in the [ Fig.2B ], the photonic device 100 may also include second means 720 configured to dissipate heat that may be emitted by the laser source towards the support layer 200.

[0075] The second means 720 include second vias 721 that extend from the waveguide 400 to the main face 200A. More specifically, the second vias 721 extend into the first layer 301 if it is considered ([ Fig.6 ]).

[0076] Additionally, the second means 721 may also include a metallic insert 722, generally flat in shape, interposed between the second vias 721 and the main face 200A. The second means 720 may also include terminal second vias 723 extending from the metallic insert 722 to the main face 200A.

[0077] It is understood that all the elements forming the secondary heat dissipation means may include an electrically conductive material, and in particular a metal, for example copper. It is understood, without needing to be explicitly stated, that the secondary vias, the metallic insert, and the secondary via terminals are interconnected.

[0078] Thus, when heat is emitted by the laser source, it is dissipated by means of the first means 700 and the second means 720. In this respect, the second means 720 dissipates the heat into the support layer 200. The implementation of the first and second means results in a temperature difference between the laser source and the heat dissipation plate of less than 8°C. The implementation of the second means alone would result in a temperature difference between the substrate 200 and the laser source of 13°C to 17°C.

[0079] As illustrated in the [ Fig.2B ], the photonic device 100 also includes third means 740 configured to dissipate heat that may be emitted by the laser source to the support layer 200. The third means 740 include third vias 741, 742 which extend from, respectively, the first pad 601 and the second pad 602 to the main face 200A ([ Fig.7 ]).

[0080] The third means 740 also include two metallic inserts, referred to respectively as the first insert 743 and the second insert 744, which are generally flat in shape. The first insert 743 is in contact with the third via 741, which extends from the first pad 601, and is interposed between the main face 200A and said third via 741. The second insert 744 is in contact with the third via 742, which extends from the second pad 602 and is interposed between the main face 200A and said third via 742.

[0081] Advantageously, the metal insert 722, the first insert 743, and the second insert 744 are formed from a single metal layer. In other words, the distance separating an insert from the main face is the same for each of the inserts.

[0082] The third means 740 may further include one or more third terminal vias 745 extending from the first insert 743 to the main face 200A, and one or more other third terminal vias 746 extending from the second insert 744 to the main face 200A.

[0083] It is understood that all the elements forming the third means 740 may include an electrically conductive material, and in particular a metal, for example copper.

[0084] These third means 740 taken in combination with the first means and the second means make it possible to observe a temperature difference between the laser source and the heat dissipation plate of less than 7°C.

[0085] The photonic device 100 may also include coupling means configured to inject laser radiation emitted by the laser source into an optical fiber or an optical fiber array.

[0086] According to a first example, the coupling means are configured to allow coupling by a slice, called coupling slice 200C, of ​​said device perpendicular to the main face 200A. This aspect is illustrated in the [ Fig.8 Advantageously, the coupling means comprise a waveguide 804, a lens 800 associated with the coupling slice 200C. These coupling means thus make it possible to couple the light radiation emitted by the laser source to an external device, for example, to an optical fiber array 801.

[0087] According to a second example, the coupling means include an 803 diffraction grating disposed in the photonic layer and configured to allow optical coupling via the front face of the laser radiation emitted by the laser source and an optical fiber or an optical fiber array. This aspect is illustrated in the [ Fig.9 ].

[0088] The invention is obviously not limited to a single laser source. In this respect, a person skilled in the art, as illustrated in [ Fig.10 [ ] can consider a photonic device 100 equipped with a plurality of photonic chips 101, and a thermal transfer layer in contact with the first and second pads 601 and 602. According to this configuration, the coupling edges of each of the photonic chips 101 can be coplanar. Furthermore, the first terminals 211 and the second terminals 212, arranged on the support face 210A, are opposite a face of the photonic chips facing the coupling edge 200C.

[0089] As illustrated in the [ Fig.11 The photonic device 100 may also include a driver chip 420 and a modulator 450 (the latter notably including a waveguide encapsulated in the photonic layer). The driver chip 420 rests on two connector pads 421 and 422 accessible from the front panel 100A. Metal balls 423 and 424 may be placed between the connector pads and the front panel. The photonic device 100 may include an auxiliary heat dissipation layer 703 thermally coupling the driver chip to the heat dissipation plate 702. The auxiliary heat dissipation layer 703 is made of the same material as the heat dissipation layer 701.

[0090] The photonic device 100 also includes other heat dissipation means 430 and 440 which essentially reproduce the characteristics of the second and third dissipation means in order to dissipate the heat that may be generated at the level of the driver chip 420 and the modulator 450.

[0091] To the [ Fig.12 ], we can see the photonic device 100 according to a second embodiment of the present invention which essentially reproduces the elements relating to the first embodiment.

[0092] According to this second embodiment, the support face is assembled to the photonic layer by the upper face by means of metal balls 607, 608 also ensuring the electrical connection of the first 601 and second 602 pads with the first terminal 211 and the second terminal 212. The support substrate 210 comprises, according to this second embodiment, a through opening 213 passing through the support substrate from the support face to the free face, said through opening being configured to allow the positioning of the first means 700.

[0093] The photonic device 100 according to this second embodiment can also include an additional substrate 220 on one face of which is assembled the secondary face 200B of the support layer 200 as well as the lens 800 and the optical fiber network 801.

[0094] To the [ Fig.13 ], we can see the photonic device 100 according to a third embodiment of the present invention which essentially reproduces the elements relating to the first embodiment.

[0095] According to this third embodiment, the transfer layer 701 comprises two secondary metal studs, respectively called first secondary stud 703 and second secondary stud 704 accessible by a contact face 701A of the transfer layer 701 opposite the upper face 300B.

[0096] A first metal ball 705, for example made of AuSn, connects the first secondary pin 703 and the first pin 601, and a second metal ball 706 connects the second secondary pin 704 and the second pin 602.

[0097] The first terminal 211 and the second terminal 212 (not shown on the [ Fig.13 ] for clarity) are electrically connected, respectively, to the first secondary block 703 and the second secondary block 704 via redistribution lines.

[0098] According to this third embodiment, the transfer layer 701 advantageously comprises silicon or AlN. These two materials are particularly suitable for forming connection means and redistribution lines.

[0099] The present invention therefore proposes an effective solution for dissipating the heat that may be emitted by an operating laser and thus ensuring its stability. In particular, the present invention proposes implementing initial means for dissipating the heat that may be produced by the laser source, which cooperate with means for connecting said laser source.

[0100] A manufacturing process for the photonic device may involve manufacturing steps that are well known in the field of microelectronics.

[0101] Of course, the invention is not limited to the embodiments described and alternative embodiments can be made without departing from the scope of the invention as defined by the claims. références

[0102] [1] S. Menezo et al., "Back-Side-On-BOX heterogeneous laser integration forfully integrated photonic circuits on silicon" 45th European Conference on Optical Communication (ECOC 2019), 2019, pp. 1-3 ; [2] M. N. Sysak et al., "Hybrid Silicon Laser Technology: A Thermal Perspective" in IEEE Journal of Selected Topics in Quantum Electronics, vol. 17, no. 6, pp. 1490-1498, Nov.-Dec. 2011 ; [3] C. Zhang et al., "Thermal Management of Hybrid Silicon Ring Lasers for High Temperature Operation" in IEEE Journal of Selected Topics in Quantum Electronics, vol. 21, no. 6, pp. 385-391, Nov.-Dec. 2015 ; [4] US 2014 / 0376857 A1.

Claims

1. Photonic device (100) comprising a photonic chip (101) and a support substrate (210), the support substrate (210) being provided with a support face (210A), the photonic chip (101) comprising a support layer (200) and a photonic layer (300) resting by its face, referred to as the lower face (300A), on a main face (200A) of the support layer (200), said photonic layer (300), which comprises at least one dielectric material, encapsulates at least one laser source formed by a waveguide (400) and a photonic stack (500) optically coupled together, the photonic stack being made of III-V semi-conductor materials, the photonic chip also comprises a first (601) and a second (602) metal pad having, respectively, a first (601A) and a second (602A) surface, accessible by an upper face (300B) of the photonic layer (300) opposite the lower face (300A), and electrically connected to the photonic stack (500) by means of connection vias (603, 604) that extend in the photonic layer (300), the first pad (601) and the second pad (602) are configured to allow the circulation of an electric current in the photonic stack (500) in order to control the emission of laser radiation by the laser source, the photonic device further comprises: - first heat dissipation means (700) which are configured to dissipate the heat capable of being emitted by the laser source, the first means (700) comprising a transfer layer (701) and a transfer element (702) in thermal contact with the transfer layer (701), characterized in that the transfer layer (701) comprises an electrically insulating material which at least partially covers at least one of the first and the second surface (601A, 602A); - connection means which are configured to electrically connect the first pad (601) and the second pad (602) with a first terminal (211) and a second terminal (212) arranged on either the support substrate (210) or the transfer layer (701).

2. Photonic device (100) according to claim 1, wherein the transfer layer (701) is in contact with the first pad (601) and the second pad (602).

3. Photonic device (100) according to claim 1 or 2, wherein the transfer layer (701) is made of a material, referred to as transfer material, which has a thermal conductivity greater than or equal to 20 W / m / K, the transfer layer (701) advantageously comprising at least one of the materials selected from: a polymer material, AIN or silicon.

4. Photonic device (100) according to one of claims 1 to 3, wherein the waveguide (400) is made of silicon, or of silicon nitride or of a hybrid form of silicon nitride and of silicon.

5. Photonic device (100) according to one of claims 1 to 4, wherein said photonic device also comprises second means (720) which are configured to dissipate the heat capable of being emitted by the laser source toward the support layer (200), the second means (720) comprise second vias (721) that extend, in the direction of the main face (200A), from the waveguide (400).

6. Photonic device (100) according to claim 5, wherein the second means (720) also comprise a metal insert (722) which is generally planar in shape and positioned between the second vias (721) and the main face (200A), the second means further comprise second terminal vias (723) that extend from the metal insert (722) toward the main face (200A), an additional insert is advantageously inserted between the main face and the second terminal vias.

7. Photonic device (100) according to one of claims 1 to 6, wherein said photonic device also comprises third means (740) which are configured to dissipate the heat capable of being emitted by the laser source, the third means (740) comprise third vias (741, 742) that extend in the direction of the main face (200A) from the first pad (601) and the second pad (602), respectively.

8. Photonic device (100) according to claim 7, wherein the third means (740) also comprise two metal inserts, referred to as first insert (743) and second insert (744), respectively, which are generally planar in shape, the first insert (743) being positioned between the main face (200A) and the third via (741) that extends from the first pad (601), the second insert (744) being positioned between the main face (200A) and the third via (742) that extends from the second pad (602), the third means (740) further comprising at least one third terminal via (745) that extends from the first insert (743) toward the main face (200A), and at least one other third terminal via (746) that extends from the second insert (744) toward the main face (200A).

9. Photonic device (100) according to one of claims 1 to 8, wherein the support face (210A) is assembled with a face of the support layer (200), referred to as the secondary face (200B), opposite the main face (200A) of said support layer.

10. Photonic device (100) according to claim 9, wherein the covering of one of the first and the second surface (601A, 602A) by the transfer layer (701) is partial, and leaves access free to a first section (601B) and a second section (602B), respectively, of the first surface (601A) and the second surface (602A), a first wire (605) directly connects the first terminal (211) and the first pad (601), while a second wire (606) directly connects the second terminal (212) and the second pad (602), the first terminal (211) and the second terminal (212) being arranged on the support substrate (210).

11. Photonic device (100) according to claim 9, wherein the transfer layer (701) comprises two secondary metal pads, referred to as first secondary pad (703) and second secondary pad (704), respectively, which are accessible by a contact face (701A) of the transfer layer (701) opposite the upper face (300B), a first metal ball (705) connecting the first secondary pad (703) and the first pad (601), and a second metal ball (706) connecting the second secondary pad (704) and the second pad (602), the first terminal (211) and the second terminal (212) are arranged on the contact face (701A), the first terminal (211) and the first secondary pad (703) are connected via a first redistribution line, while the second terminal (212) and the second secondary pad (704) are connected via a second redistribution line.

12. Photonic device (100) according to one of claims 1 to 8, wherein the support face is assembled to the photonic layer by the upper face by means of metal balls (607, 608) also ensuring the electrical connection of the first and second pads with, respectively, the first terminal and the second terminal, the support substrate comprising a through-opening (213) passing through the support substrate of the support face toward a face of the support substrate opposite the support face, said through-opening being configured to allow the positioning of the first means.

13. Photonic device (100) according to one of claims 1 to 12, wherein said photonic device (100) comprises coupling means which are configured to inject laser radiation emitted by the laser source into an optical fiber or a network of optical fibers.

14. Photonic device (100) according to claim 13, wherein the coupling means are configured to allow coupling by an edge, referred to as the coupling edge (200C), of said device perpendicular to the main face (200A), advantageously the coupling means comprise a lens (800) associated with the coupling edge.

15. Photonic device (100) according to claim 13, wherein the coupling means comprise a diffraction grating (803) arranged in the photonic layer (300) and configured to allow optical coupling by the upper face of the laser radiation emitted by the laser source and an optical fiber or a network of optical fibers.