Classifications

• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
  • H01S5/00—Semiconductor lasers
  • H01S5/40—Arrangement of two or more semiconductor lasers, not provided for in groups H01S5/02 - H01S5/30
  • H01S5/42—Arrays of surface emitting lasers
  • H01S5/423—Arrays of surface emitting lasers having a vertical cavity
• • G—PHYSICS
  • G02—OPTICS
  • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
  • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
  • G02B6/24—Coupling light guides
  • G02B6/42—Coupling light guides with opto-electronic elements
  • G02B6/4201—Packages, e.g. shape, construction, internal or external details
  • G02B6/4202—Packages, e.g. shape, construction, internal or external details for coupling an active element with fibres without intermediate optical elements, e.g. fibres with plane ends, fibres with shaped ends, bundles
• • G—PHYSICS
  • G02—OPTICS
  • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
  • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
  • G02B6/24—Coupling light guides
  • G02B6/42—Coupling light guides with opto-electronic elements
  • G02B6/4201—Packages, e.g. shape, construction, internal or external details
  • G02B6/4249—Packages, e.g. shape, construction, internal or external details comprising arrays of active devices and fibres
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
  • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
  • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
  • H01L21/04—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer
  • H01L21/50—Assembly of semiconductor devices using processes or apparatus not provided for in a single one of the subgroups H01L21/06 - H01L21/326, e.g. sealing of a cap to a base of a container
  • H01L21/56—Encapsulations, e.g. encapsulation layers, coatings
  • H01L21/563—Encapsulation of active face of flip-chip device, e.g. underfilling or underencapsulation of flip-chip, encapsulation preform on chip or mounting substrate
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
  • H01L23/00—Details of semiconductor or other solid state devices
  • H01L23/34—Arrangements for cooling, heating, ventilating or temperature compensation ; Temperature sensing arrangements
  • H01L23/36—Selection of materials, or shaping, to facilitate cooling or heating, e.g. heatsinks
  • H01L23/367—Cooling facilitated by shape of device
  • H01L23/3677—Wire-like or pin-like cooling fins or heat sinks
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
  • H01L23/00—Details of semiconductor or other solid state devices
  • H01L23/34—Arrangements for cooling, heating, ventilating or temperature compensation ; Temperature sensing arrangements
  • H01L23/42—Fillings or auxiliary members in containers or encapsulations selected or arranged to facilitate heating or cooling
  • H01L23/433—Auxiliary members in containers characterised by their shape, e.g. pistons
  • H01L23/4334—Auxiliary members in encapsulations
• • G—PHYSICS
  • G02—OPTICS
  • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
  • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
  • G02B6/24—Coupling light guides
  • G02B6/42—Coupling light guides with opto-electronic elements
  • G02B6/4201—Packages, e.g. shape, construction, internal or external details
  • G02B6/4219—Mechanical fixtures for holding or positioning the elements relative to each other in the couplings; Alignment methods for the elements, e.g. measuring or observing methods especially used therefor
  • G02B6/4228—Passive alignment, i.e. without a detection of the degree of coupling or the position of the elements
  • G02B6/4232—Passive alignment, i.e. without a detection of the degree of coupling or the position of the elements using the surface tension of fluid solder to align the elements, e.g. solder bump techniques
• • G—PHYSICS
  • G02—OPTICS
  • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
  • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
  • G02B6/24—Coupling light guides
  • G02B6/42—Coupling light guides with opto-electronic elements
  • G02B6/4201—Packages, e.g. shape, construction, internal or external details
  • G02B6/4246—Bidirectionally operating package structures
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
  • H01L2224/00—Indexing scheme for arrangements for connecting or disconnecting semiconductor or solid-state bodies and methods related thereto as covered by H01L24/00
  • H01L2224/01—Means for bonding being attached to, or being formed on, the surface to be connected, e.g. chip-to-package, die-attach, "first-level" interconnects; Manufacturing methods related thereto
  • H01L2224/10—Bump connectors; Manufacturing methods related thereto
  • H01L2224/15—Structure, shape, material or disposition of the bump connectors after the connecting process
  • H01L2224/16—Structure, shape, material or disposition of the bump connectors after the connecting process of an individual bump connector
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
  • H01L2224/00—Indexing scheme for arrangements for connecting or disconnecting semiconductor or solid-state bodies and methods related thereto as covered by H01L24/00
  • H01L2224/73—Means for bonding being of different types provided for in two or more of groups H01L2224/10, H01L2224/18, H01L2224/26, H01L2224/34, H01L2224/42, H01L2224/50, H01L2224/63, H01L2224/71
  • H01L2224/732—Location after the connecting process
  • H01L2224/73201—Location after the connecting process on the same surface
  • H01L2224/73203—Bump and layer connectors
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
  • H01L2224/00—Indexing scheme for arrangements for connecting or disconnecting semiconductor or solid-state bodies and methods related thereto as covered by H01L24/00
  • H01L2224/73—Means for bonding being of different types provided for in two or more of groups H01L2224/10, H01L2224/18, H01L2224/26, H01L2224/34, H01L2224/42, H01L2224/50, H01L2224/63, H01L2224/71
  • H01L2224/732—Location after the connecting process
  • H01L2224/73201—Location after the connecting process on the same surface
  • H01L2224/73203—Bump and layer connectors
  • H01L2224/73204—Bump and layer connectors the bump connector being embedded into the layer connector
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
  • H01L2224/00—Indexing scheme for arrangements for connecting or disconnecting semiconductor or solid-state bodies and methods related thereto as covered by H01L24/00
  • H01L2224/73—Means for bonding being of different types provided for in two or more of groups H01L2224/10, H01L2224/18, H01L2224/26, H01L2224/34, H01L2224/42, H01L2224/50, H01L2224/63, H01L2224/71
  • H01L2224/732—Location after the connecting process
  • H01L2224/73251—Location after the connecting process on different surfaces
  • H01L2224/73253—Bump and layer connectors
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
  • H01L2924/00—Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
  • H01L2924/01—Chemical elements
  • H01L2924/01079—Gold [Au]
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
  • H01L2924/00—Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
  • H01L2924/013—Alloys
  • H01L2924/0132—Binary Alloys
  • H01L2924/01322—Eutectic Alloys, i.e. obtained by a liquid transforming into two solid phases
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
  • H01L2924/00—Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
  • H01L2924/10—Details of semiconductor or other solid state devices to be connected
  • H01L2924/11—Device type
  • H01L2924/13—Discrete devices, e.g. 3 terminal devices
  • H01L2924/1304—Transistor
  • H01L2924/1305—Bipolar Junction Transistor [BJT]
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
  • H01L2924/00—Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
  • H01L2924/15—Details of package parts other than the semiconductor or other solid state devices to be connected
  • H01L2924/151—Die mounting substrate
  • H01L2924/1515—Shape
  • H01L2924/15151—Shape the die mounting substrate comprising an aperture, e.g. for underfilling, outgassing, window type wire connections
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
  • H01L2924/00—Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
  • H01L2924/15—Details of package parts other than the semiconductor or other solid state devices to be connected
  • H01L2924/161—Cap
  • H01L2924/1615—Shape
  • H01L2924/16152—Cap comprising a cavity for hosting the device, e.g. U-shaped cap
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
  • H01S5/00—Semiconductor lasers
  • H01S5/02—Structural details or components not essential to laser action
  • H01S5/022—Mountings; Housings
  • H01S5/0225—Out-coupling of light
  • H01S5/02251—Out-coupling of light using optical fibres
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
  • H01S5/00—Semiconductor lasers
  • H01S5/02—Structural details or components not essential to laser action
  • H01S5/022—Mountings; Housings
  • H01S5/023—Mount members, e.g. sub-mount members
  • H01S5/02325—Mechanically integrated components on mount members or optical micro-benches
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
  • H01S5/00—Semiconductor lasers
  • H01S5/02—Structural details or components not essential to laser action
  • H01S5/022—Mountings; Housings
  • H01S5/0233—Mounting configuration of laser chips
  • H01S5/0234—Up-side down mountings, e.g. Flip-chip, epi-side down mountings or junction down mountings
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
  • H01S5/00—Semiconductor lasers
  • H01S5/02—Structural details or components not essential to laser action
  • H01S5/022—Mountings; Housings
  • H01S5/0235—Method for mounting laser chips
  • H01S5/02355—Fixing laser chips on mounts
  • H01S5/0237—Fixing laser chips on mounts by soldering
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
  • H01S5/00—Semiconductor lasers
  • H01S5/02—Structural details or components not essential to laser action
  • H01S5/024—Arrangements for thermal management
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
  • H01S5/00—Semiconductor lasers
  • H01S5/10—Construction or shape of the optical resonator, e.g. extended or external cavity, coupled cavities, bent-guide, varying width, thickness or composition of the active region
  • H01S5/18—Surface-emitting [SE] lasers, e.g. having both horizontal and vertical cavities
  • H01S5/183—Surface-emitting [SE] lasers, e.g. having both horizontal and vertical cavities having only vertical cavities, e.g. vertical cavity surface-emitting lasers [VCSEL]

Definitions

• the present invention relates to a method for manufacturing electronic and optoelectronic circuits. It applies, in particular, to the manufacture of optoelectronic circuits and, even more particularly, to the improvement of the thermal behavior of a semiconductor laser emitter.
• an optical emission sub-assembly integrates the control electronics necessary for supplying the currents and bias voltages of the laser component and the laser itself.
• Such an assembly can take several different forms: silicon support or other semiconductor integrating the interconnection lines between the different elements, silicon support or other structured semiconductor where the interconnections are made from wires.
• the laser operating in such a subassembly sees its temperature increase and vary according to the external temperature conditions but also according to the conditions and the level of electrical injection.
• Laser or VCSEL the same types of problems mentioned above are encountered and are often amplified, in particular in the case of lasers with vertical emission from quaternary materials on InP substrate for long emission wavelengths (1.25 ⁇ m at 1.65 ⁇ m). Indeed, the so-called Bragg mirrors consisting of periodic stacks of GalnAsP and InP materials are poor thermal conductors and do not allow temperature operation of this type of laser.
• the present invention aims to avoid or at least significantly reduce thermal problems for lasers with lateral and vertical emission.
• the present invention provides different types of micro-assembly depending on the nature of the laser (lateral or vertical emission) using the transfer by turning the laser component on a semiconductor with high thermal conductivity, microbeads serving as both electrical conductors for the laser control signals and thermal conductors for cooling the laser.
• the present invention relates to an assembly comprising an electronic component, characterized in that said electronic component is connected by microbeads to at least one heat sink, said balls being connected to electrically conductive lines on said electronic component and to electrically conductive lines on at least one heat sink, said balls conveying, on the one hand, electrical signals between the electronic component and each heat sink carrying said electrically conductive lines and, on the other hand, by heat conduction, heat from the electronic component to each heat sink.
• the assembly as succinctly described above comprises a coating which coats balls, at least a part of the electronic component and at least a part of a heat sink, said coating being a thermal conductive element but a electrical insulator.
• At least one heat sink is integrated into a housing of the electronic component. According to particular features, at least one heat sink also forms part of a housing of the electronic component. According to particular characteristics, at least one heat sink integrates a current and modulation generator and / or electronics allowing the operation and / or the control of the electronic component. According to particular characteristics, a heat sink is made from a semiconductor material and in that a second heat sink is made of a metallic or semiconductor element carried over. According to particular characteristics, at least one heat sink has a hole opposite said electronic component and in that said component is an optoelectronic component. According to particular characteristics, the assembly as succinctly described above comprises an optical fiber in said hole.
• the present invention relates to a method of assembling an electronic component, characterized in that it comprises: - a step of preparing at least one heat sink so that, on at least one said heat sink, electrically conductive lines are connected to ball supports and - a step of connection, by microbeads, of said electronic component to at least one heat sink, said balls being connected to electrically conductive lines on said electronic component and to ball supports on the heat sink, said balls conveying, on the one hand, electrical signals between the electronic component and each heat sink carrying said electrically conductive lines and, on the other hand, by heat conduction, heat from the electronic component to each heat sink.
• the process d ⁇ assembly as succinctly described above comprises a step of closing a housing comprising at least one said heat sink.
• the invention applies similarly to laser components with lateral and vertical emission.
• the present invention also relates to a method and a device for coupling optical components. It applies, in particular, to the coupling of an optical fiber to a component emitting or receiving light signals.
• the need to produce optoelectronic modules for high-speed fiber optic networks (10 GBd and more), at low cost and by seeking minimized geometric dimensions has led to the development of optical sub-assemblies based on the use of optoelectronic chips.
• VCSEL laser type (acronym for Vertical Cavity Surface Emitting Lasers for lasers with emitting surface in vertical cavity or laser emitting on surface) in the case of emitters or of photodiode type (PIN type with reverse polarization or Avalanche) in the case of receivers .
• Various methods have been used to achieve optical coupling from the laser to the optical fiber or from the optical fiber to the photodiode.
• the emitting component consists of the transfer of the emitting chip VCSEL on a silicon substrate. A hole is formed through the substrate so that a fiber previously cleaved and then inserted into the hole is guided by the latter and is positioned passively (i.e.
• the self-aligning properties of the fusible balls used by the flip-chip technology make it possible to guarantee the repeatability of positioning of the chip relative to the hole guiding the optical fiber, the latter being itself positioned relative to the chip. and fixed to the substrate by passive alignment.
• the fiber is not guided directly into the substrate but bonded into a ceramic capillary (known as a "ferrule") itself guided in a hole formed through the substrate.
• flip-chip technology allows lateral and transverse positioning (that is to say in the two axes of the plane of the substrate) of the optical fiber relative to the chip (see, for example the request US2003 / 0098511, Moon et al.), however the fiber retains a degree of freedom in the optical axis, which makes its axial position relative to the chip and therefore the optical power coupled in the fiber difficult to control. These two quantities are in fact directly linked.
• the present invention aims to remedy these drawbacks.
• the present invention aims, according to its second and third aspects, a device and a method for coupling optical components making it possible to ensure control of the position of the optical face of the fiber relative to the emissive or sensitive surface. of the optoelectronic chip used as transmitter or receiver, and a device resulting from the implementation of this method.
• the present invention relates to an optoelectronic device having a predetermined coupling rate, characterized in that it comprises: - a substrate on which is transferred at least one optoelectronic component, - at least one calibrated hole passing through the substrate, each calibrated hole being opposite an electronic component and intended for guiding an optical fiber in the direction of said optoelectronic component and - at least one optical fiber fixed in a fiber holder, and projecting from said fiber holder by a predetermined length, the projecting part being inserted in a said hole, opposite an optoelectronic component, in such a way that, when said fiber holder is in abutment on the surface of the substrate opposite to the mounting surface of the optoelectronic component, the gap between the active surface of the optoelectronic component and the end of the optical fiber corresponds to the predetermined coupling rate.
• the positioning of the optical fiber can be carried out passively, that is to say without supplying a laser or measuring the amount of light passing through the optical fiber or received by the photodiode, which simplifies and makes more economical the construction of the coupling device.
• the implementation of a fiber holder allows excellent repeatability of the respective placement of the fiber relative to the optoelectronic component. It is observed that the predetermined coupling rate can be voluntarily limited so as not to exceed coupled power levels in the fiber incompatible with the ocular safety levels required by the standards in force.
• at least one optoelectronic component is a laser.
• At least one laser is of the VCSEL type, that is to say Vertical Cavity Surface Emitting Laser or laser with emitting surface in vertical cavity.
• the device as succinctly explained above comprises, on said substrate, for at least one optoelectronic component, its control or pilot circuit and electrical tracks connected on the one hand to the control circuit and, on the other hand, to the optoelectronic component and allowing the propagation of a microwave signal between said pilot control circuit and said laser.
• at least one optoelectronic component is a photodiode.
• at least one photodiode is of the PIN or Avalanche type.
• the optoelectronic device as briefly described above comprises, on the same substrate: - a plurality of optoelectronic components, - a plurality of calibrated holes passing through the substrate, each calibrated hole being opposite an optoelectronic component and being intended for guiding an optical fiber in the direction of said optoelectronic component and - a plurality of optical fibers fixed in a fiber holder, each fiber projecting from said fiber holder by a predetermined length, this projecting part being inserted into a said hole in look of the associated optoelectronic component, so that, when said fiber holder abuts on the surface of the substrate opposite to the mounting surface of the optoelectronic components, the distance between the active surface of each optoelectronic component and the end of the fiber associated optic corresponds to the predetermined coupling rate.
• the predetermined length of the protruding parts is not necessarily identical for all the fibers.
• said holes are arranged on lines each comprising at least three holes.
• at least one hole has a shape whose diameter of the inscribed circle is greater than the diameter of an optical fiber and whose inscribed circle has, with said shape, three contact points forming a substantially equilateral triangle. Thanks to these arrangements, the fiber can be positioned precisely in the hole while leaving space so that by capillarity, glue can fill the space between the edges of the hole and the fiber. Indeed, the distance between the fiber and the edges of the hole is variable over the circumference of the fiber.
• at least one fiber holder takes the form of a ferrule.
• said fiber holder is made up of several parts fixed together, the part in contact with the fiber being a capillary provided with a hole whose diameter is close to the outside diameter of the fiber.
• the parts in question can be fixed in different ways, for example by fitting, gluing or welding.
• at least one fiber holder consists of at least one part carrying at least one groove in which an optical fiber can be at least partially inserted to block the optical fiber by clamping said part against another part.
• This fiber holder is conventionally called "v-groove", or block of fiber ves.
• the end of at least one optical fiber is cleaved.
• the end of at least one optical fiber is lensed or with an extended core.
• the optical coupling is optimized and repeatable.
• the cleavage has an angle relative to the plane perpendicular to the fiber.
• the end of at least one optical fiber is cleaved and covered with an anti-reflective treatment.
• parasitic reflections at the fiber / air interface are limited.
• said angle takes a value between 4 and 8 ° to prevent the reflected light flux from being re-coupled in the laser cavity, or towards the fiber network.
• the gap between the active surface of the optoelectronic component and the end of the optical fiber is filled with a transparent material whose optical index is close to that of the optical fiber.
• the present invention relates to a method of manufacturing a device as succinctly described above having a predetermined coupling rate, characterized in that it comprises: - a step of transfer, on a substrate, of '' at least one optoelectronic component, - a step of producing at least one calibrated hole passing through said substrate, each calibrated hole being opposite an optoelectronic component and being intended for guiding an optical fiber in the direction of said optoelectronic component and a step of inserting, in at least one hole, an protruding part of predetermined length (L) of an optical fiber fixed in a fiber holder and of fixing said optical fiber to said substrate opposite an optoelectronic component , when said fiber holder is in abutment on the surface of the substrate opposite to the mounting surface of the optoelectronic component, the difference between the active surface of the opto
• the positioning of the optical fiber can be carried out passively, that is to say without supplying a laser or measuring the amount of light passing through the optical fiber or received by the photodiode, which simplifies and makes more economical the construction of the coupling device.
• at least one optoelectronic component is a laser.
• at least one laser is of the VCSEL type, that is to say Vertical Cavity Surface Emitting Laser or laser with emitting surface in vertical cavity .
• the step of transferring at least one optoelectronic component there is also transferred, on said substrate, for at least one optoelectronic component, a driver control circuit, and electrical tracks connected to on the one hand to the pilot control circuit and, on the other hand, to the optoelectronic component and allowing the propagation of a microwave signal between said pilot control circuit and said laser.
• at least one optoelectronic component is a photodiode.
• at least one photodiode is of the PIN or Avalanche type.
• said holes are arranged on lines each having at least three holes.
• at least one hole has a shape whose diameter of the inscribed circle is greater than the diameter of an optical fiber and whose inscribed circle has, with said shape, three contact points forming a substantially equilateral triangle.
• at least one fiber holder takes the form of a ferrule.
• the end of at least one optical fiber is cleaved.
• the cleavage of said fiber has an angle relative to the plane perpendicular to the fiber.
• the method as succinctly explained above comprises a step of filling the gap between the active surface of the optoelectronic component and the end of the optical fiber with a transparent material whose optical index is close to that of optical fiber.
• a "flip-chip” method is used during the transfer step.
• the step of transfer by a “flip-chip” method comprises a step of transfer of metallized studs onto said substrate, a step of depositing a fusible material on said metallized studs and, a step of re- melting of said fusible material during which the fusible material takes the form of a ball of controlled diameter.
• the transfer step by a "flip-chip” method comprises a transfer step, on the optoelectronic component, of metal studs corresponding with the position of the balls of the substrate.
• the present invention also relates to an optoelectronic device and a method of manufacturing said device. It applies, in particular, to the control and regulation of the power of emission of a laser with emission by the surface known as VCSELs (acronym of Vertical Cavity Surface Emitting Laser).
• VCSELs lasers also have a certain number of advantages compared to wafer emission lasers, in particular their collective testability on wafer, the greater ease of coupling in standard optical fibers, etc.
• the use of these components is done after placing in a box, traditionally in so-called TO (Transistor Outline) or TOSA (Transmitter Optical Sub Assembly) boxes, respectively provided with a window allowing the light beam to pass through or with a device allowing the connection of a connector to optical fiber.
• TO Transistor Outline
• TOSA Transmitter Optical Sub Assembly
• this problem is conventionally resolved by taking advantage of the parasitic reflections encountered by the beam at the level of the exit window of the housing: this fraction of the beam, reflected, can be detected by a photodiode: - placed in the vicinity of the VCSEL laser, as proposed document US 5,905,750 (Lebby et al.), - on which the VCSEL laser is placed, as proposed by document GB 2,351,180 (Oskarsson et al.), or - positioned behind the VCSEL laser, as proposed by document US 5,737,348 (Smith et al.).
• the window on which part of the light emitted by the VCSEL laser is reflected can also be tilted relative to the axis of emission of the laser beam in order to redirect part of it to the control photodiode, placed alongside the VCSEL as proposed in document WO 99/34487 (Smith et al.).
• Other methods have also been proposed: - the monolithic integration of the detector and of the VCSEL laser chip, as proposed in document US 5,943,357 (Lebby et al.), - lateral detection by the VCSEL laser of its spontaneous emission by a detector produced in the vicinity, as proposed in document US Pat. No.
• the present invention relates to a device making it possible to control the power of the VCSEL laser by detecting the light power emitted on the side of the substrate on which the VCSEL laser, generally epitaxial, has been produced.
• the present invention relates to an optoelectronic device, characterized in that it comprises: - a laser with vertical emission the emission of which is done on the one hand on a face called “useful" opposite an optical system using the rays emitted by said useful face of said laser and, on the other hand, on a face opposite to said useful face and - an optoelectronic sensor adapted to capture all or part of the light emitted by the laser by the opposite side to the useful side.
• the light emitted by the laser on the face opposite the useful face which is used to detect a malfunction of the laser or to control and regulate the light power emitted by the laser, which avoids having to provide a optical device on the side of the useful face of the laser.
• the production and installation of a sensor on this face opposite the useful face are easy since no other optical component is there.
• Other advantages of the present invention are a higher monitored power, increasing the signal / noise ratio and a repeatability of the increased power level compared to the state of the art.
• the sensor can thus be used to detect a possible malfunction of the VCSEL or to regulate its average power.
• a receiving substrate carrying the laser by the face opposite to the useful face is drilled by a hole between the laser and the optoelectronic sensor. Thanks to these provisions, even if the material of the receiving substrate absorbs the light rays emitted by the laser, the optoelectronic sensor can capture part of the light emitted by the laser, through the bore of the receiving substrate.
• the optoelectronic device as briefly described above comprises, on said receiving substrate, for at least one laser, a driver control circuit and electrical tracks connected on the one hand to the control circuit of pilot and, on the other hand, laser and allowing the propagation of a microwave signal between said pilot control circuit and said laser. Thanks to these arrangements, the laser can emit optical microwave signals.
• the optoelectronic sensor and the laser are each attached, by fusible balls, to a main substrate carrying at least one optical fiber. Thanks to these provisions, the so-called “flip-chip” or “IBM C4" assembly technique can be implemented, which ensures very good precision and very high repeatability in the manufacture of the optical sub-assembly, thus avoiding to have to turn on the laser to perform the positioning or calibration of the sensor.
• the optoelectronic sensor comprises a photodiode.
• said photodiode is of PIN type and / or of avalanche type.
• the optoelectronic sensor comprises an anti-reflection layer facing said laser. This avoids loss of light by reflection or scattering.
• the optoelectronic device as succinctly explained above comprises an optical fiber facing the useful face of the laser. Thanks to these provisions, the device can be used to transmit optical signals remotely, for example to convey telecommunication signals.
• the optoelectronic device as succinctly described above comprises: - a plurality of vertical emission lasers, the emission of which is carried out on the one hand on a face called “useful" opposite an optical system putting using the rays emitted by said useful face of said laser and, on the other hand, on a face opposite to said useful face, said plurality of lasers being transferred onto at least one receiving substrate and - for each laser, an optoelectronic sensor adapted to capture all or part of the light emitted by the laser from the face opposite the useful face.
• each VCSEL laser is then provided with a control photodiode individually measuring its power through its host substrate. Indeed, in this case, the use of reflection on a part of the housing would not allow the respective powers of the VCSELs lasers to be discriminated.
• the present invention relates to a method for manufacturing an optoelectronic device, characterized in that it comprises: - a step of transferring, onto a receiving substrate, a laser with vertical emission, the emission of which is done on the one hand on a face called “useful" opposite an optical system using the rays emitted by said useful face of said laser and, on the other hand, on a face opposite to said useful face and - a step positioning an optoelectronic sensor adapted to capture all or part of the light emitted by the laser from the face opposite the useful face.
• the method as succinctly set out above comprises a step of drilling the receiving substrate carrying the laser by its face opposite to its useful surface, preceding the step of positioning the optoelectronic sensor.
• the advantages, aims and characteristics of the method being similar to those of the device as succinctly set out above, they are not repeated here.
• the present invention also relates to a device making it possible to control the power of the VCSEL laser by detecting, directly, without reflection, the light power emitted on the side of the useful surface of the VCSEL laser, on a main substrate which carries an optical fiber.
• the present invention relates to an optoelectronic device, characterized in that it comprises a main substrate carrying: - an optical fiber, - a receiving substrate carrying a laser with vertical emission, the emission of which takes place on a face called “useful" opposite said optical fiber and - an optoelectronic sensor placed opposite the useful side lb laser, near the entry face of the optical fiber and adapted to capture part of the light emitted by the laser in the direction of the main substrate.
• the light emitted by the laser on the side of the optical fiber without reflection on a surface, which is used to detect a malfunction of the laser or to control and regulate the light power emitted by the laser, this which avoids providing a complex optical device and undergoing fouling effects from a reflection surface.
• the production and installation of a sensor on the main substrate are easy.
• the optoelectronic device can be used to transmit optical signals remotely, for example to convey telecommunication signals.
• Other advantages of the present invention are a higher monitored power, increasing the signal / noise ratio and a repeatability of the increased power level compared to the state of the art.
• the sensor can thus be used to detect a possible malfunction of the VCSEL or to regulate its average power.
• the optoelectronic device as briefly described above comprises, on said receiving substrate, for at least one laser, a driver control circuit and electrical tracks connected on the one hand to the control circuit of pilot and, on the other hand, laser and allowing the propagation of a microwave signal between said pilot control circuit and said laser. Thanks to these arrangements, the laser can emit optical microwave signals. According to particular characteristics, the laser receiving substrate is attached, by fusible balls, to the main substrate. Thanks to these arrangements, the so-called “flip-chip” or "IBM C4" assembly technique can be implemented, which ensures very good precision and very high repeatability in the manufacture of the device, thus avoiding having to turn on the laser to perform positioning or calibration of the sensor.
• the optoelectronic sensor comprises a photodiode.
• said photodiode is of the metal-semiconductor-metal type. Thanks to these provisions, the manufacturing cost of said sensor is very low.
• the laser receiving substrate carries a mirror on the face of this substrate opposite the useful face of said laser. Thanks to these arrangements, the power of the laser is increased.
• the optoelectronic sensor comprises an antireflection layer facing said laser. This avoids loss of light by reflection or scattering.
• the optoelectronic device as succinctly described above comprises a main substrate carrying: - a plurality of optical fibers, - at least one receiving substrate carrying a plurality of lasers with vertical emission whose remission takes place on a face called “useful" opposite an optical fiber of said plurality of optical fibers and -
• an optoelectronic sensor placed near the input face of the corresponding optical fiber and adapted to capture part of the light emitted by said laser towards the main substrate.
• the present invention is thus particularly well suited to the case where it is necessary to simultaneously control several VCSELs lasers placed in the same housing: each VCSEL laser is then provided with a photodiode for monitoring individually measuring its power.
• the present invention relates to a method for manufacturing an optoelectronic device, characterized in that it comprises: - a step of transferring, onto a main substrate, a receiving substrate carrying a laser with vertical emission, the emission takes place on a so-called "useful" face and an optoelectronic sensor placed opposite the useful face of the laser, close to the input face of the optical fiber and adapted to capture part of the light emitted by the laser towards the main substrate and - a step of positioning an optical fiber near said optoelectronic sensor and facing said useful surface of said laser.
• the present invention also relates to a method and a device for encapsulating an electronic component.
• Encapsulation and / or packaging technologies are becoming more and more critical both in terms of performance, hermeticity, resistance to shocks and vibrations and resistance to variations and thermal cycles, as well as in terms of cost.
• the final presentation or “packaging” of a component or subsystem tends to be most often specific and must satisfy both the integrity constraints of the component or subsystem at the same time as 'to the constraints of a user-friendly interface in terms of its integration into any system.
• the added difficulty then is in maintaining the efficiency of the optical coupling after soldering and on the embrittlement of the optical fiber after soldering due to constraints induced by the parameters of the soldering process in particular. temperature.
• the final cost for example of a laser in an airtight housing, is often prohibitive because of the techniques used and the low manufacturing yields.
• Numerous researches are devoted to the production of packages on silicon wafer aiming at directly integrating the package with its circuit or with its multicircuit assembly.
• the Anglo-Saxon terminology used for these concepts is "wafer level packaging" or the case at the level of the substrate.
• the object of certain aspects of the present invention is to use the housing techniques at the level of the wafer by resolving the points mentioned above, namely: - achieving hermeticity at one point from an electrical point of view than from an optical point of view by techniques other than glass-to-metal welds and - obtaining substantial savings in terms of cost.
• the invention also aims to achieve, collectively and by conventional microelectronics technologies, a series of boxes on edge with characteristics which allow the assembly to be carried out collectively.
• the invention proposes a solution for producing the hermeticity seal of the housing at low temperature.
• the invention also relates to the production of sealed electrical and / or optical bushings making it possible to interface the active electrical and / or optical elements incorporated inside the sealed housing with the external environment.
• the present invention aims to avoid the “ground plane” effect, which disturbs the transmitted signals, generated by the metal case when the latter is too close to a microwave line.
• the present invention relates to a method of encapsulation of at least one electronic component, which comprises: - a step of preparing a substrate comprising making a first layer of dielectric material on a first face of said substrate, - a step of producing a conductive line on said first layer of dielectric material, - a step of drilling a hole from a second face of the substrate opposite said first face to the conductive line and - a step of filling said hole with a conductive material.
• the method as succinctly described above comprises a step of producing a second layer of dielectric material on the first layer of dielectric material and on the conductive line. Thanks to these provisions, the risks of the hole damaging the conductive line are reduced. According to a ninth aspect, to avoid the problems of positioning, provision is made, on the edges of the housing bearing on the substrate, for a reduction in the section of the housing, compared to the average thickness of the housing. A “knife” is thus formed which sinks into the substrate, or into an intermediate layer integral with the substrate and serving as a seal between the substrate and the housing.
• the present invention relates to a method of encapsulation of at least one electronic component which comprises: - a step of preparing a housing having, on its edges intended to be supported on the substrate carrying each said electronic component, a thickness at least twice as thin as the average thickness of said housing and - a step of positioning said housing on said substrate, said knife then being supported on said substrate.
• the ninth aspect of the present invention relates to an encapsulation method which comprises: - a step of preparing a substrate carrying each said electronic component so that it has, opposite the edges of a housing intended to be in support on said substrate, a knife having a thickness at least twice as thin as the average thickness of said housing and - a step of positioning said housing on said substrate, said edges then being supported on said knife.
• said edges have an essentially triangular section. Thanks to these provisions, the support of the housing on the substrate is very concentrated and prevents subsequent sliding movements of the housing on the substrate.
• the method as succinctly described above comprises a step of producing a joint of ductile material on which said knife comes to bear during the positioning step.
• the knife can sink into said seal and ensure a better seal, in particular when the interior volume of the housing is placed under vacuum.
• said ductile material comprises Indium.
• the encapsulation method as succinctly set out above comprises a step of evacuating, at least partially, the volume constituted by said case and said substrate. Thanks to these arrangements, the position of the housing on the substrate is maintained by the vacuum created inside the housing.
• the vacuum considered is preferably such that the residual pressure is less than 10 "4 torr.
• metal is melted, in a pumping pipe, initially placed at the outlet of said pipe. Thanks to these provisions, the obturation of the pumping pipe is easy and final.
• the metal to be melted initially has the shape of a ball.
• the metal to be melted comprises Indium. Thanks to each of these arrangements, a micro-valve is produced at the outlet of the pumping pipe and, with heating of the ball to a temperature of approximately 170 ° C., said pipe is closed. According to particular characteristics, during the melting of said metal, a slight overpressure is applied to the outside of the housing, relative to the vacuum, at least partial, inside the housing. Thanks to these provisions, the molten metal is sucked inside the pipe to be closed.
• the method as succinctly set out above comprises the encapsulation of several components on the same substrate with several housings then the cutting of the substrate to separate the encapsulated components with their housings. Thanks to these provisions, the cost of encapsulating electronic components is reduced. According to a tenth aspect, the present invention aims to reduce the complexity of producing an optical link between an optoelectronic component, for example a laser or a photodiode, and an optical fiber extending outside of a housing comprising said component. optoelectronics.
• an optoelectronic component for example a laser or a photodiode
• the present invention relates to a method of encapsulation of an optoelectronic component using light in a predetermined spectral band, which comprises: - a step of preparing a housing to constitute a window therein of material at least partially transparent in said spectral band, - a step of positioning said housing opposite said optoelectronic component so that said window is facing said component and - a step of positioning an optical fiber on said housing such that an end face of said optical fiber is located opposite said window.
• said housing is made of at least partially transparent material in said spectral band.
• the tenth aspect of the present invention relates to a method of encapsulation of an optoelectronic component using a spectral band of light, which comprises: - a step of preparing the substrate to constitute therein a window of at least partially transparent material in said spectral band, - a step of positioning said optoelectronic component on said substrate, so that said window is facing said component and - a step of positioning an optical fiber on said housing so that one side end of said optical fiber is located opposite said window.
• said window has a thickness of less than 100 ⁇ m.
• said material at least partially transparent in said spectral band is quartz.
• quartz is transparent for the wavelength of 5 850nm and silicon between 1310nm and 1550nm, these wavelengths being commonly used in optoelectronics.
• said optoelectronic component is transferred to said housing by a technology implementing balls of fusible material. This technology is known as the "flip-chip".
• the positioning of the optoelectronic component relative to the window is thus very precise, in each dimension.
• An eleventh aspect of the present invention aims to increase the positioning accuracy of a housing relative to an electronic component carried on a substrate.
• the present invention relates to an encapsulation process, characterized in that it comprises: - a step of constituting, on the substrate and on at least part of the edges of the housing, supports of ball or cylinder of a fusible material, - a step of depositing fusible material on at least a portion of said ball or cylinder supports, 0 - a step of melting said fusible material, to form said balls or cylinder with precisely determined dimensions and - a step of positioning ball or cylinder supports not yet carrying said balls or cylinder on said balls or cylinders. Thanks to these provisions, the positioning of the housing on the substrate is very precise and is controlled by the presence of the balls.
• the present invention relates to a device for encapsulating at least one electronic component, characterized in that it comprises: - a substrate, - a first layer of dielectric material on a first face of said substrate, - a line conductive on said first layer of dielectric material, a hole extending from a second face of the substrate opposite said first face to the conductive line.
• the present invention relates to a device for encapsulating at least one electronic component which comprises: - a substrate carrying each said electronic component and 0 - a housing having, on its edges intended to be supported on said substrate, a knife with a thickness at least twice as thin as the average thickness of said housing.
• the present invention relates to a device for encapsulating at least one electronic component, which comprises: - a housing and - a substrate carrying each said electronic component which has, opposite the edges of a housing intended to be supported on said substrate, a knife having a thickness at least twice as thin as the average thickness of said housing.
• the present invention relates to a device for encapsulating an optoelectronic component implementing a spectral light band, which comprises: - a housing having a window of material at least partially transparent in said spectral band opposite said spectrum component and - an optical fiber positioned on said housing such that an end face of said optical fiber is located opposite said window.
• the present invention relates to a device for encapsulating an electronic component which comprises: - on at least part of the edges of a housing, ball or cylinder supports of a fusible material, - a substrate carrying said component and, opposite the edges of the housing, ball or cylinder supports of a fusible material, - balls or a cylinder connecting said ball or cylinder supports.
• FIG. 1a shows, schematically, a section of a conventional wafer emission laser having a contact on the front face and a contact on the rear face
• - Figure 1b shows, schematically, a laser with conventional wafer emission having the two contacts on the front face
• - Figures 2a and 2b show a block diagram of the invention and an example of laser assembly and heat sink as proposed in the invention
• - Figures 3a to 3k show, schematically, a manufacturing method of the invention in the case of a laser with lateral emission or the two contacts are located on the same face
• - Figure 4 shows, schematically, an application of the invention to the particular case of a vertical emission laser
• - Figure 5 shows, schematically, in perspective, a first particular embodiment of a device object of the present invention, after assembly
• - Figure 6 shows, schematically and in front view, the first embodiment illustrated in
• FIGS. 1 to 4 relate to the first aspect of the present invention
• FIGS. 5 to 13 relate to the second and third aspect of the present invention
• FIGS. 14 to 18 relate to the fourth and fifth aspect of the present invention
• Figures 22 to 32 to the eighth to fifteenth aspect of the present invention.
• Each aspect of the invention can be considered a full-fledged invention, but the different aspects of the present invention are intended to be combined to manufacture electronic circuits and, in particular, optoelectronic circuits.
• FIG. 1a represents the conventional stack of semiconductor laser diodes well known to those skilled in the art.
• FIG. 1b relates to the same conventional laser structure where the contact on the rear face is transferred to the face by additional etching steps. These two structures are produced in the form of manipulable chips.
• FIG. 2a proposes the block diagram of the invention and its application to the case of a laser diode with lateral emission where the contacts are front face and rear face, figure 2b and only on the front face, figure 2c.
• the block diagram of the invention, Figure 2a is shown in its final form. It is clear that the production process itself contributes to the original character of the assembly and will be described below.
• the invention consists in hybridizing by inversion with solder balls 107 (so-called “flip chip” technique) an optical or electronic component 108 on a semiconductor support 106, for example made of silicon, where the lines d interconnections necessary for the operation of component 108.
• Other types of support are possible such as: silicon carbide, aluminum nitride, gallium nitride.
• the current generator and modulation of the laser diode can be integrated on the only heat sink reported.
• at least one of the dissipative supports will be able to integrate the electronics allowing the operation and / or the control of the laser diode.
• the solder balls 107 make the electrical connections and make it possible to drain the heat from the component in operation towards the semiconductor substrate which constitutes a good heat sink. It is clear to a person skilled in the art that the greater the number of balls 107, the greater the contact surface and the more efficient the thermal drainage to the substrate 106.
• a coating process with a thermally conductive but electrically insulating polymer element makes it possible to improve the thermal resistance and solidify the whole.
• the rear face of the component 108 can then be used to integrate either by deposition or also by transfer a second heat sink 109 made of metallic materials (Gold, Copper, for example) or known for their great thermal conduction properties (carbide of silicon, aluminum nitride, gallium nitride).
• a second heat sink 109 made of metallic materials (Gold, Copper, for example) or known for their great thermal conduction properties (carbide of silicon, aluminum nitride, gallium nitride).
• the electrical connection of the lasers is thus carried out at the same time as the heat sinks are directly on the rear face of the laser or by transfer of a material with high thermal conductivity.
• This assembly and method can be directly applied to the assembly of laser diodes covering the range of wavelengths going from 0.6 ⁇ m to 2 ⁇ m according to the two configurations (contacts front and rear face, figure 1a, and contacts on the front face, figure 1b
• Figure 2b shows an example of configuration
• the second heat sink is deferred and welded by balls 107. It also makes it possible to ensure the electrical connection on the rear face of the laser diode 112 via balls 109 connected to the component supply lines integrated on the semiconductor substrate 106.
• a second coating 110 makes it possible to solidify the assembly and also to improve the thermal contact between 109 and 112. In the particular case of a laser diode having the two contacts on the front face, the assembly is then very close to the principle diagram.
• the transfer of the second heat sink can in this case be carried out either - by growth é direct electrolytic of the metal on the rear face of the component on thicknesses greater than 50 ⁇ m by transfer of a block of metal bonded by an adhesive with good thermal conduction.
• the dissipator can then be completely integrated into the housing or be the housing which clearly improves the heat exchange surface. It is this second particular case which is represented in FIG. 2c.
• FIG. 3 proposes and details an example of a modular manufacturing process according to the geometrical and topological characteristics of the laser used. It applies to lasers with lateral emission with n and p contacts on the front face as well as to lasers with vertical emission called VCSEL.
• This substrate can be made of silicon, the most commonly used, but also of various semiconductor materials, for example aluminum nitride (AIN), Gallium nitride (GaN), diamond.
• AIN aluminum nitride
• GaN Gallium nitride
• all of the solder balls 107 will be produced, FIG. 3b, by conventional techniques. These balls will preferably be small around 20 ⁇ m in diameter so that they can be positioned as much as possible.
• Resins 114 are then carried out, a conventional process in microelectronics. Polishing the assembly makes it possible to planarise and free the rear face of the component, Figure 3e. Polishing also makes it possible to eliminate all or part of the substrate on which the laser has been produced and which generally is of GaAs or InP material considered to be poor thermal conductors. This is particularly recommended in the case of lasers with vertical emission. From this step, a metallic bonding deposit 115 is produced on the entire substrate, FIG. 3f, subsequently allowing the electrolytic deposition of this same metal or of another metal. At this stage, the size of the dissipator can be defined using conventional resin and photolithography techniques, Figure 3g.
• the deposition is then carried out on thicknesses ranging from a few tens of microns to 100 ⁇ m, Figure 3h.
• the steps shown in FIGS. 3i, 3j and 3k consist in eliminating the different layers of resins with solvents, thus freeing the entire stack from the device. These steps are technological steps known to those skilled in the art.
• the manufacturing process in the case of a vertical emission laser is similar. It nevertheless has the difference that we will clarify. It is thus necessary to make a hole in the starting substrate allowing the emission of light downwards without absorption in the substrate 106
• the final assembly is shown in FIG. 4. This hole can serve as a guide for the fiber. This feature can be avoided if the starting substrate is transparent to the laser emission wavelength.
• This type of assembly is particularly interesting for laser applications requiring the generation of high powers but also for operations with high intensity modulation (for example operation of laser diodes with high modulation frequency of 10 GHz and above) without having to use an external Peltier type cooler.
• the substrate in this flip chip configuration of the component, the substrate can be completely removed and replaced by a material with high dissipation power.
• the heat is removed as close as possible to the semiconductor junction.
• a conventional thinning can hardly be pushed below a thickness of 100 ⁇ m of substrate without posing handling problems.
• the invention is also directly applicable to electronic power devices such as bipolar transistors, field effect transistors which are components having two contacts on the front face and whose architecture and materials are compatible with the process described. Second and third aspects.
• a substrate 501 previously equipped with metallized pads 511 (see Figures 8 and 12) allowing the transfer by flip-chip technology of various electronic and optoelectronic components, in particular an optoelectronic component 502, its circuit control 503 and one or more electronic components (integrated circuits) 504 (in the figures, a single component 504 is shown) necessary for the control of the optoelectronic component 502 or to the conversion of the detected signal if the component is a detector, for example a photodiode, as well as the passive electronic components necessary for their operation (not shown).
• an optoelectronic component 502 its circuit control 503 and one or more electronic components (integrated circuits) 504 (in the figures, a single component 504 is shown) necessary for the control of the optoelectronic component 502 or to the conversion of the detected signal if the component is a detector, for example a photodiode, as well as the passive electronic components necessary for their operation (not shown).
• the optoelectronic component 502 is, for example, a vertical emission laser VCSEL for the emission of a light signal in an optical fiber 507 or a PIN or avalanche photodiode, for detection and reception of a light signal coming from the fiber optical 507.
• the substrate 501 can be made of various materials (Silicon, Alumina, Quartz, ...) compatible with the production on at least one of its faces of conductive tracks (not shown) adapted to the propagation of an electrical signal microwave.
• metallized studs can be produced on which a fusible material, for example indium, is deposited, capable of re-forming into balls of controlled diameter, typically between 5 ⁇ m and 500 ⁇ m.
• the optoelectronic component 502 is fitted with metal studs coincident with the position of the balls of the substrate 501.
• the use of a flip-chip type transfer is motivated by the good microwave performance of this technology and by its self-alignment properties of the component 502 thus making it possible to control its position relative to the hole 510 for guiding the optical fiber 507. Therefore, the present invention achieves passive alignment of the optical fiber 507 and of the optoelectronic component 502 in the plane of the substrate 501.
• the substrate 501 illustrated in front view in FIG.
• the hole 510 produced in the substrate 501 can be obtained by various methods such as dry etching or laser drilling.
• the shape of the hole 510 is not necessarily circular: it can be any geometric shape in which a circle of the diameter of the optical fiber to be inserted can be inscribed, typically from 125 to 130 ⁇ m (see FIG. 11).
• the optical fiber 507 for example made of silica, is mounted maintained by gluing or any other fixing means (soldering, welding, glass-glass sealing, etc.).
• This fiber holder or ferrule 506 appears in section view in FIGS. 7 and 8. It consists a capillary 508, for example made of ceramic, containing the optical fiber 507, the capillary 508 being inserted into an external body 509 which may be made of metal or any other material.
• the part of the fiber holder 506 in contact with the optical fiber 507 is the capillary 508, provided with a hole whose diameter is close to the outside diameter of the optical fiber 507.
• the parts constituting the fiber holder 506 can be fixed between them in different ways, for example by fitting, gluing or welding.
• the optical fiber 507 can be single-mode or multi-mode depending on the intended application and the emission wavelength used.
• a portion 512 of the optical fiber 507 protrudes from the fiber holder or ferrule 506 by a length L determined in advance by knowing the evolution of the coupled power of the laser in the fiber or of the fiber in the photodiode, depending the distance between these two components and the thickness of the substrate 501.
• the protruding length L can be controlled with a very low dispersion, for example using a method of cleavage or cutting of the optical fiber 507 by laser, or a method of polishing the end of the optical fiber 507.
• FIG. 8 illustrates the final configuration of the optical module a once the fiber holder or ferrule 506 assembled to the substrate 501, the part 512 of the optical fiber 507 which protrudes from the fiber holder 506 being inserted into the hole 510 until the fiber holder and the substrate 501 are brought into contact.
• distance between the active area of the optoelectronic component and the substrate is determined by the height h of the fusible balls 511, known with precision. The residual difference e between the optoelectronic component and the optical fiber 507 is therefore worth (see FIG.
• the protrusion length L is determined so that once the optical fiber 507 is placed in the hole 510 and the fiber holder 506 being in abutment on the surface of the substrate 501 opposite the mounting surface of the optoelectronic components, the residual difference e between the active surface of the optoelectronic component 502 and the cleaved end of the corresponding optical fiber 507 at the desired light coupling rate.
• the desired coupling rate can be deliberately limited so as not to exceed coupled power levels in the fiber incompatible with the ocular safety levels required by the standards in force.
• the present invention achieves passive alignment of the optical fiber 507 and the optoelectronic component 502 in the direction perpendicular to the plane of the substrate 501.
• the space of thickness e separating the optical fiber 507 and the optoelectronic component 502 can besides being filled with an adhesive or other transparent material (see FIG. 12) whose optical index is close to that of optical fiber 507, for example 1.5, for certain glasses or silicas.
• the end of the optical fiber 507 can also be equipped with a microlens (not shown) and / or be with an extended core and / or covered with an anti-reflective treatment, in order to optimize the coupling rate of the optoelectronic component and the optical fiber 507.
• the operations for preparing the substrate 501 and transferring the optoelectronic component 502 and the electronic components 503 and 504 are carried out collectively on a plate (wafer) of the same material, this plate being subsequently cut out to the dimensions of an individual substrate 501.
• the manufacturing cost is thus reduced by a collective approach.
• FIG. 9 It can be seen in FIG. 9 that the present invention, the characteristics of which are described above for a single optoelectronic component 502, can be easily implemented in so-called parallel optics applications in which it is desired to align several lasers simultaneously.
• vertical emission or several photodiodes 522 to an optical fiber ribbon 540 the number of which is, typically 4, 8 or 12.
• the optical fiber ribbon 540 is placed in a fiber holder or multi-fiber ferrule
• the substrate 521 is, for its part , pierced with the number of holes 530 corresponding to the number of optoelectronic components 522 to be coupled to the optical fiber ribbon 540.
• the optical fibers 540 once mounted in the fiber holder 526, are spaced apart by a typical distance of 250 ⁇ m and are guided by holes 530 drilled in the substrate 521, facing which have been transferred by “flip-chip” respectively an equal number of optoelectronic components, for example vertical emission lasers or photodiodes. All of the optoelectronic components can be arranged in a strip or in a two-dimensional matrix. Preferably, the holes 530 are arranged on lines each comprising at least three holes 530. In FIG.
• the ribbon of optical fibers 540 and the fiber holder 526 consisting of at least one (here two) part 535 carrying at least one groove 536 in which an optical fiber 527 can be at least partially inserted.
• Each optical fiber 527 is locked in position in the fiber holder 526 by clamping, one against the other of the pieces 535 or, if there is only one piece 535 having grooves, by clamping this piece 535 against a flat part without grooves conventionally called "counter blade”.
• a hole 510 or 530 used in the embodiments illustrated in Figures 5 to 10.
• This hole has a shape whose diameter of the inscribed circle is greater than the diameter of an optical fiber 507 or 527 and the inscribed circle of which has, with said shape, three contact points forming a preferentially substantially equilateral triangle.
• the optical fiber can be positioned precisely in the hole while leaving space so that, by capillarity, glue whose optical index is close to that of the optical fiber can fill the space between the edges of the hole and the fiber since the distance between the fiber and the edges of the hole is variable over the circumference of the optical fiber.
• FIG. 12 in section, an optical coupling between an optical fiber 507 or 527 and an optoelectronic component, 502 or 522 is observed. The end of the optical fiber is cleaved in order to optimize the coupling of the light.
• This cleavage is carried out, in the embodiment shown, with an angle between 4 and 8 ° which limits the stray reflections at the interface of the optical fiber.
• the residual difference e between the optical fiber and the optoelectronic component is, in the embodiment shown, filled with a transparent material 550, for example an ultraviolet crosslinkable adhesive, the optical index of which is close to that of the fiber. optical, to reduce the reflection of light on the fiber.
• an optical coupling rate is determined which it is desired to obtain repetitively and precisely between an optical fiber and an optoelectronic component and the difference e between these elements which corresponds to this rate of determination is determined. coupling and the value of the length L of the part of the optical fiber which will protrude from the fiber holder, taking into account the values of the thickness s of the substrate and the height h of the fusible balls.
• a substrate is prepared and optoelectronic and electronic components are transferred onto a plate (wafer) of the same material, using a "flip-chip" process with balls of diameter h.
• the transfer step by a "flip-chip” method comprises a transfer step of metallized studs on the substrate 606, a step of depositing a fusible material on said metallized studs.
• the step of transfer by a "flip-chip” method also includes a step 607 of transfer, on the optoelectronic component, of metal studs corresponding with the position of the balls of the substrate.
• the transfer step comprises a step 608 of placing the metal studs of the components and the metallized studs on the substrate.
• the transfer step comprises a step of re-melting 609 of the fusible material during which the fusible material takes the form of a ball of controlled diameter.
• the plate is cut to the dimensions of an individual substrate.
• a step 620 at least one optical fiber is inserted into a fiber holder and these two elements are joined.
• a cleavage of each optical fiber is carried out so that the part of the fiber which protrudes from the fiber holder has a length L.
• the cleavage is carried out at an angle relative to the axis of optical fiber, to limit stray reflections.
• a fiber fixed in a fiber holder is inserted into at least one hole.
• the optical fiber and the fiber holder are fixed to the substrate, for example by bonding or soldering, opposite an optoelectronic component, said fiber holder being at the end of the assembly step in abutment on the surface of the substrate opposite to the mounting surface of the optoelectronic component.
• an adhesive is used, for example, the optical index of which is close to that of the fiber which, by capillary action, fills the space between the optical fiber and the hole.
• FIG. 14 shows an optoelectronic device 700 comprising a main substrate
• a hole 720 is made opposite the active area of the VCSEL laser 710 for optical coupling of the laser and an optical fiber
• the main substrate 705 can be made of various materials (Silicon, Alumina, Quartz, ...) compatible with the production on at least one of its faces of conductive tracks (not shown) suitable for propagation of a microwave electrical signal.
• metallized studs are produced on which a fusible material is deposited, capable of re-forming into balls 717 of controlled diameter, typically between 20 ⁇ m and 500 ⁇ m. This is the micro-ballooning process known as a "flip-chip".
• the receiving substrate 707 is thus linked to the main substrate 705 by a metallization allowing positioning of the “flip-chip” type by means of balls 717 of fusible metal (Indium, AuSn or other eutectic alloy) themselves placed on pads metallic themselves made on the main substrate 705.
• the receiving substrate 707 of the laser 710 is equipped with metal studs coincide with the position of the balls 717 of the main substrate 705.
• the diameter of the fusible balls 717 is chosen according to the final height of the VCSEL.
• the balls 717 ensure both the mechanical positioning and the electrical connection of the photodiode to other components carried by the main substrate 705.
• the use of a flip-chip type transfer is motivated by the good microwave performance of this technology and its self-alignment properties of the receiving substrate 707 of the laser 710, thus making it possible to control its position relative to the main substrate 705.
• the hole 720, produced in the main substrate 705, can be obtained by various methods such as than dry etching or laser drilling.
• the shape of the hole 720 is not necessarily circular: it can be any geometric shape in which a circle of the diameter of an optical fiber 725 to be inserted can be inscribed, typically from 125 to 130 ⁇ m.
• a photodiode 730 is manufactured separately from the VCSEL 710 laser and it is then transferred, with a substrate 732 which carries it, by the same flip chip technique using the 734 microbeads, the active zone generally being on the front face, which implies to return it.
• the photodiode 730 is positioned, on the main substrate 705, opposite the face of the VCSEL laser 710 opposite its useful emission face 715.
• the receiving substrate 707 is absorbent at the emission wavelength of the VCSEL 710 laser.
• the substrate 707 is provided with an opening 735 on this opposite face, opening through which the photodiode 730 receives part of the light emitted by the laser 710.
• the opening 735 is made by drilling the receiving substrate 707 after the epitaxial growth of the laser VCSEL 710.
• the hole in the rear face of the VCSEL laser 710 is produced after transfer by laser flip chip of the laser 710 to the main substrate 705.
• a coating step is added which The hole in the rear face of the VCSEL 710 laser is produced after transfer by laser flip chip of the laser 710 to the main substrate 705.
• a coating step is added which makes it possible to solidify or harden the entire substrate assembly.
• the photodiode 730 is transferred over the laser 710. Two components are thus stacked one on top of the other. Once positioned and connected by means of the balls 734, the photodiode 730 detects the light power emitted by the face of the VCSEL 710 opposite the useful emission face.
• a control and regulation circuit receives the signal emitted by the photodiode 10 730 and, depending on its intensity, modifies the electric power supplied to the laser 710, so that the maximum light power emitted by this laser 710 remains substantially constant over time, to compensate for the aging of the laser 710.
• the optical fiber 725 for example made of silica, is mounted held by bonding or any other fixing means (soldering, welding, ).
• One of the faces of the fiber holder 740 is in contact with the face of the main substrate 705 opposite the face receiving the receiving substrate 707 of the laser 710.
• This fiber holder or ferrule 740 consists of a capillary, for example ceramic, containing the optical fiber 725, the capillary being inserted into an external body which may be made of metal or any other material.
• the optical fiber 725 can be monomode or multimode depending on the intended application and the emission wavelength used. Part of the optical fiber 725 protrudes from the fiber holder or ferrule 740 by a length L determined in advance by knowing the evolution of the coupled power of the laser 710 in the fiber 725, as a function of the difference between these two components and the thickness of the main substrate 705.
• the protrusion length L can be controlled with very low dispersion, for example by using a cleavage or cutting process of the optical fiber 25 725 by laser, or a polishing process from the end of the optical fiber 725.
• the protrusion length L is determined so that once the optical fiber 725 is placed in the hole 720 and the fiber holder 740 is in abutment on the surface of the main substrate 705 opposite to the mounting surface of the receiving substrate 707 of the laser 710, the residual difference e between the active surface of the laser 710 and the cleaved end of the optical fiber 725 corresponding to the coupling rate of the light sought.
• the desired coupling rate can be deliberately limited so as not to exceed coupled power levels in the fiber incompatible with the ocular safety levels required by the standards in force. Therefore, the present invention achieves passive alignment of the optical fiber 725 and the laser 710 in the direction perpendicular to the plane of the main substrate 705.
• the space of thickness e separating the optical fiber 725 and the laser 710 can in addition to being filled with an adhesive or other transparent material whose optical index is close to that of optical fiber 725, for example approximately 1.5 for certain glasses or silicas.
• the optical fiber 725 can also be equipped with a microlens at the end (not shown) in order to optimize the coupling rate of the laser 710 and the optical fiber 725.
• FIGS. 15A and 15B show, in the form of a flow diagram, steps implemented in a particular embodiment of the method which is the subject of the present invention.
• a light power is determined which one wishes to collect on the photodiode, during the life of the VCSEL laser.
• a VCSEL laser is prepared by epitaxy on a host substrate.
• the main substrate is prepared.
• a hole is drilled necessary for the passage of an optical fiber, in the main thick substrate.
• the hole is calibrated, passes through the main substrate, is opposite a VCSEL laser and is intended for guiding an optical fiber towards the useful face of the VCSEL laser.
• step 804 optoelectronic and electronic components are transferred to a wafer of the same material, using a "flip-chip" process with balls of fusible material.
• the transfer step by a "flip-chip” method comprises a transfer step of metallized studs on the main substrate 805, a step of depositing a fusible material on said metallized studs.
• the step of transfer by a "flip-chip” method also includes a step 806 of transfer, on the host substrate carrying the laser, of metal studs corresponding with the position of the balls of the main substrate.
• the transfer step comprises a step 807 of placing the metal studs of the receiving substrate and the metallized studs on the main substrate.
• the transfer step comprises a re-melting step 808 of the fusible material during which the fusible material takes the form of a ball of controlled diameter.
• the receiving substrate is pierced on the face opposite the useful face of the VCSEL laser until reaching the emitting layer of the laser.
• the drilling is, for example, carried out by a method of dry etching, laser drilling or mechanical machining.
• To locally pierce the host substrate of the VCSEL laser it may be useful to thin this host substrate in order to allow the carrying out of a photolithography step.
• a pattern is thus defined above the emission zone of the laser and the material is etched locally. The dimensions of this hole are defined so as not to isolate the current injection area.
• a selective etching method makes it possible to stop etching on the first layers of Bragg mirror (alumina alloy).
• a step 810 optoelectronic and electronic components are transferred to a plate (wafer) of the same material, using a "flip-chip" process with balls of fusible material.
• the substrate carrying the photodiode, a control circuit and electrical tracks connected on the one hand to the control circuit and, on the other hand, to the photodiode, which allow the propagation of a signal between said signal, are reported. control circuit and said photodiode.
• the transfer step 810 by a "flip-chip” method, comprises a step of transferring metallized studs onto the main substrate, a step of depositing a fusible material on said metallized studs, a step of transferring, onto the substrate of the photodiode, of metal pads corresponding with the position of the balls of the main substrate, a step of matching the metal pads of the substrate of the photodiode and of the metallized pads on the main substrate, and a step of re-melting the material fuse during which the fusible material takes the form of a ball of controlled diameter.
• the photodiode is thus opposite the hole in the receiving substrate and the photodiode is connected to conductive lines of the main substrate.
• the control and regulation photodiode is thus positioned so that it covers the VCSEL laser and is placed in the beam emitted by the VCSEL laser, on its face opposite its useful surface. Therefore, the beam extracted from the rear of the VCSEL laser is converted into current by the photodiode and can thus be used to detect a possible malfunction of the VCSEL and / or to regulate its average power.
• a step 811 an optical fiber is inserted into a fiber holder and these two elements are joined.
• a step 812 (FIG. 15B)
• a cleavage of the optical fiber is carried out so that the part of the fiber which protrudes from the fiber holder has a length L.
• the cleavage is carried out at an angle relative to the axis of the optical fiber, to limit stray reflections.
• a fiber fixed in a fiber holder is inserted into at least one hole.
• the optical fiber holder is fixed to the main substrate, for example by gluing or soldering, facing a laser, said fiber holder being at the end of the assembly step in abutment on the surface of the main substrate opposite the mounting surface of the host substrate on the main substrate.
• an adhesive is used, for example, the optical index of which is close to that of the fiber which, by capillary action, fills the space between the optical fiber and the hole.
• step 815 the gap between the active surface of the optoelectronic component and the end of the optical fiber is filled with a transparent material whose optical index is close to that of the optical fiber.
• step 816 the light power emitted by this laser is measured with the photodiode placed on the same receiving substrate, and, in step 817, this power is controlled by regulation, according to techniques known per se. .
• FIG. 16 shows a variant of the invention adapted to the case where it is necessary to control and regulate the respective powers of several lasers VCSELs 710 integrated, each on a host substrate 707.
• the ribbon of optical fibers 725 is placed in a fiber holder or multi-fiber ferrule 775 or a block of so-called "v-grooves" and a collective cleavage of the optical fibers 725 is carried out such that each optical fiber 725 protrudes from the fiber holder by a determined length L.
• the substrate main common 755 is pierced by the number of holes 750 corresponding to the number of lasers 710 to be coupled to optical fibers 725.
• the embodiments set out above with reference to FIGS. 14 to 16 are suitable for cases where the receiving substrate is absorbent at the emission wavelength of the VCSEL laser.
• the material is transparent at 1310nm while it absorbs at 850nm.
• FIGS. 17 and 18 are adapted to the case where the receiving substrate is, at least partially, transparent to the emission length of the VCSEL laser.
• a step 904 of partial removal of the receiving substrate 745 is carried out by mirror quality polishing.
• an anti-reflection layer is applied to the polished surface of the receiving substrate 745, so as to avoid loss of
• a substrate carrying the photodiode 730 is transferred to the main substrate, during step 905.
• steps 811 to 817 are carried out.
• the thinning of the receiving substrate 745 on the rear face of the VCSEL 710 laser is carried out after transfer by flip chip of the laser 710 to the main substrate 705.
• a coating step is added which makes it possible to solidify or harden all host substrate - main substrate and 0 to continue conventional technological operations always at the wafer scale on the deferred components. Once these operations have been carried out, the photodiode 730 is transferred over the laser 710. Two components are thus stacked one above the other.
• FIG. 19 shows an optoelectronic device 1000 comprising a main substrate
• the main substrate 1005 can be made of various materials (Silicon, Alumina, Quartz, ...) compatible with the realization on at least one of its conductive track faces (not shown) adapted to the propagation of a microwave electrical signal.
• metallized pads are produced on which a fusible material is deposited, capable of re-forming into balls 1017 of controlled diameter, typically between 20 ⁇ m and 500 ⁇ m.
• the receiving substrate 1007 is thus linked to the main substrate 1005 by a metallization allowing positioning of the “flip-chip” type by means of balls 1017 of fusible metal (Indium, AuSn or other eutectic alloy) themselves placed on pads metallic themselves made on the main substrate 1005.
• the receiving substrate 1007 of the laser 1010 is equipped with metal studs coincide with the position of the balls 1017 of the main substrate 1005.
• the diameter of the fusible balls 1017 is chosen according to the final height of the VCSEL.
• the balls 1017 ensure both the mechanical positioning and the electrical connection of the photodiode to other components carried by the main substrate 1005.
• the use of a flip-chip type transfer is motivated by the good microwave performance of this technology and its self-alignment properties of the receiving substrate 1007 of the laser 1010, thus making it possible to control its position relative to the main substrate 1005.
• the hole 1020, produced in the main substrate 1005, can be obtained by various methods such as than dry etching or laser drilling.
• the shape of the hole 1020 is not necessarily circular: it can be any geometric shape in which a circle of the diameter of an optical fiber 1025 to be inserted can be inscribed, typically from 125 to 130 ⁇ m.
• a photodiode 1030 is manufactured directly on the main substrate 1005.
• the photodiode 1030 is preferably of the metal-semiconductor-metal type.
• the photodiode 1030 is preferably of the PIN type.
• the photodiode 1030 is reported. In all cases, the photodiode 1030 is positioned opposite the useful face of the laser 1010, near the direct optical path connecting the laser 1010 to the optical fiber 1025, that is to say, in the embodiment represents in Figures 19 to 21, near hole 1020.
• the photodiode 1030 is connected to a low-noise micro-amplifier and at least one low-pass filter (not shown).
• an amplifier can be provided either on the main substrate 1005, or on a remote printed circuit.
• the photodiode 1030 is provided with an anti-reflection layer over its entire surface facing the laser 1010.
• a mirror 1035 is carried over on the rear face of the VCSEL laser 1010. This mirror is carried over by known techniques in the prior art.
• the photodiode 1030 detects the light power emitted by the useful face of the VCSEL 1010 laser without any optical component is not interposed on the optical path going from the laser 1010 to the photodiode 1030, with the possible exception of a converging lens concentrating the light ray coming from the laser 1010 on the entry face of the optical fiber 1025.
• a control and regulation circuit receives the signal emitted by the photodiode 1030 and, depending on its intensity, modifies the electric power supplied to the laser 1010, in such a way that the maximum light power emitted by this laser 1010 remains substantially constant over time, to compensate for the aging of the laser 1010.
• the optical fiber 1025 for example made of silica, is mounted maintained by bonding o u any other fixing means (soldering, welding, ).
• One of the faces of the fiber holder 1040 is in contact with the face of the main substrate 1005 opposite its face receiving the receiving substrate 1007 of the laser 1010.
• This fiber holder or ferrule 1040 consists of a capillary, by example in ceramic, containing the optical fiber 1025, the capillary being inserted in an external body which can be made of metal or any other material.
• the optical fiber 1025 can be monomode or multimode depending on the intended application and the emission wavelength used. Part of the optical fiber 1025 protrudes from the fiber holder or ferrule 1040 by a length L determined in advance by knowing the evolution of the coupled power of the laser 1010 in the fiber 1025, as a function of the difference between these two components. and the thickness of the main substrate 1005.
• the protruding length L can be controlled with very little dispersion, for example by using a method of cleavage or cutting of the optical fiber 1025 by laser, or a method of polishing the end of the optical fiber 1025.
• the protrusion length L is determined so that once the optical fiber 1025 is placed in the hole 1020 and the fiber holder 1040 is in abutment on the surface of the main substrate 1005 opposite the surface of mounting the receiving substrate 1007 of the laser 1010, the residual distance e between the active surface of the laser 1010 and the cleaved end of the optical fiber 1025 corresponding to the coupling rate of the light sought .
• the desired coupling rate can be deliberately limited so as not to exceed coupled power levels in the fiber incompatible with the ocular safety levels required by the standards in force. Therefore, the present invention achieves passive alignment of the optical fiber 1025 and the laser 1010 in the direction perpendicular to the plane of the main substrate 1005.
• the space of thickness e separating the optical fiber 1025 and the laser 1010 can furthermore be filled with an adhesive or other transparent material whose optical index is close to that of the optical fiber 1025, for example approximately 1.5 for certain glasses or silicas.
• the optical fiber 1025 can also be equipped with a microlens at the end (not shown) in order to optimize the coupling rate of the laser 1010 and the optical fiber 1025.
• FIGS. 20A and 20B show, in the form of a flow diagram, steps implemented in a particular embodiment of the method which is the subject of the present invention.
• a light power is determined which one wishes to collect on the photodiode, during the life of the VCSEL laser.
• a VCSEL laser is prepared by epitaxy on a host substrate.
• the main substrate is prepared.
• a hole is drilled necessary for the passage of an optical fiber, in the main thick substrate.
• the hole is calibrated, passes through the main substrate, is opposite a VCSEL laser and is intended for guiding an optical fiber towards the useful face of the VCSEL laser.
• optoelectronic and electronic components are transferred to a wafer of the same material, using a "flip-chip" process with balls of fusible material.
• the transfer step by a "flip-chip” method comprises a transfer step of metallized studs on the main substrate 1105, a step of depositing a fusible material on said metallized studs.
• the transfer step by a "flip-chip” method also includes a step 1106 of transfer, on the host substrate carrying the laser, of metal studs corresponding with the position of the balls of the main substrate.
• the transfer step includes a step 1107 of placing the metal studs of the receiving substrate and the metallized studs on the main substrate.
• the transfer step comprises a step of re-melting 1108 of the fusible material during which the fusible material takes the form of a ball of controlled diameter.
• the control circuit connects on the one hand the control circuit and, on the other hand, the photodiode, to allow the propagation of a signal between said control circuit and said photodiode.
• the photodiode is thus opposite the useful face of the laser 1010 and close to the axis of the optical fiber.
• the control and regulation photodiode 1030 is thus positioned so that it receives light rays emitted by the laser VCSEL 1010. Therefore, the light rays emitted by the laser 1010 in the direction of photodiode 1030 are converted into 5 current through the photodiode to detect a possible malfunction of the VCSEL 1010 laser and / or to regulate its average power.
• an optical fiber is inserted into a fiber holder and these two elements are joined.
• the optical fiber is cleaved so that the part of the fiber which protrudes from the fiber holder has a length L.
• the cleavage is carried out at an angle with respect to to the axis of the optical fiber, to limit stray reflections.
• a fiber fixed in a fiber holder is inserted into at least one hole.
• the optical fiber holder is fixed to the main substrate, for example by gluing or soldering, facing a laser, said fiber holder being at the end of the assembly step in abutment on the surface of the main substrate opposite the mounting surface of the host substrate on the main substrate.
• an adhesive is used, for example, the optical index of which is close to that of the fiber which, by capillary action, fills the space between the optical fiber and the hole.
• the gap between the active surface of the optoelectronic component and the end of the optical fiber is filled with a transparent material whose optical index is close to that of the optical fiber.
• FIG. 21 shows a variant of the invention adapted to the case where it is necessary to control and regulate the respective powers of several lasers VCSELs 1010 integrated, each on a host substrate 1007. It is then reported in the same way as above photodiodes 1030 comprising as many distinct photosensitive zones as the number of VCSELs 1010 lasers. It can be seen, in FIG.
• the present invention the characteristics of which are described above for a single laser 1010, can be easily implemented in so-called parallel optics applications in which it is desired to simultaneously align several vertical emission lasers 1010 to a ribbon of optical fibers 1025, the number of which is typically 4, 8 or 12.
• the ribbon of optical fibers 1025 in a fiber holder or multi-fiber ferrule 35 1075 or a block of so-called "v-grooves" and a collective cleavage of the optical fibers 1025 is carried out such that each fiber o ptic 1025 protrudes from the fiber holder by a determined length L.
• the main substrate 1055 is, for its part, pierced with the number of holes 1050 corresponding to the number of lasers 1010 to be coupled to the optical fibers 1025.
• the operations described in FIGS. 20A and 20B are carried out for each VCSEL 1010 laser, these VCSELs 1010 lasers then being mounted on the common main substrate 1055, and a control and regulation photodiode 1030 is positioned, for each laser 1010, as indicated above.
• a substrate 1203 carrying, on a first face (the upper face in FIG. 22) a first layer of dielectric material 1201, a conductive line 1204 and a second layer of dielectric material 1202 to which a solder 1205 attaches a housing 1200.
• a bore 1206 is formed from the second face of the substrate (the lower face in FIG. 22) opposite the first face, up to the conductive line 1205, facing the interior of the housing 1200.
• the housing 1200 is for example made of silicon.
• the hole 1206 makes it possible to connect electronic components outside the housing 1200 to the electronic components 1210 located inside the housing 1200, according to known techniques.
• the drilling 1206 is carried out, preferably before the packaging by the conventional masking techniques (resin, photolithography and opening by wet or dry etching). It is then filled with metal to allow the electrical connection between the conductive line 1204 and the outside of the housing 1200. It is observed that the method of carrying out the drilling is done in two stages (the metallic conductive line 1205 ensuring the tightness vis- vis-à-vis the outside, a hole is made and then it is filled with metal, the hole need not be perfectly sealed after filling with metal). The realization of the electrical crossing shown in FIG.
• the role of the first layer of dielectric material 1201 is to isolate from the substrate all the conductive input-output lines of the electronic components 1210.
• the substrate 1203 can itself be complex and consist of a stack of levels of conduction and / or interconnections of different integrated components. The practical example describing this type of complex substrate is given by a silicon substrate integrating various electronic functions. It is observed that the silicon substrate is generally chosen with a high resistivity.
• the contacts are isolated by trenches or deposits of dielectric material are made on the walls of the hole.
• the input-output conductive lines 1204 are then produced on this first layer of dielectric material 1201 by conventional techniques of deposition by evaporation.
• a second layer of dielectric material 1202, optional, is then deposited on these conduction lines 1204, which makes it possible to mechanically reinforce these lines.
• the seal is ensured by the solder 1205, made of Indium.
• the housing 1200 is then welded to the second layer of dielectric material 1202, in a manner known per se. Thanks to this first aspect of the present invention, even when the encapsulation box of the electronic components 1210 carried by the substrate 1203 is metallic, the ground plane effect which could disturb the signals conveyed by the conductive line 1204 is avoided, by particularly if they are microwave signals since the path of these signals remains far from the edge of the housing 1200.
• a support 1401 of ball or cylinder of fusible material is deposited ( figure 23).
• This deposit is known in flip-chip technology but, instead of being applied to electronic components, it is applied to the connection of a housing on the substrate and, instead of being applied to transmission of electronic signals, it is applied to the mechanical maintenance of the housing on the substrate. Then the deposition of fusible material 1501 is carried out, as illustrated in FIG. 24. This deposition is carried out at low temperature by evaporation of the indium metal. Then the meltable material is melted and it spontaneously takes the form of a ball 1601 or a cylinder, depending on the shape of the support 1401, under the effect of the surface tension forces, as illustrated in FIG. 25. principle of depositing a metal by evaporation or any other form of deposit (electrolytic for example) and is well known to those skilled in the art.
• an open area is defined whose dimensions are better controlled than a micron and where the deposition of the indium metal or any other metal can be carried out.
• the resin is removed and this metal can be remelted to form a cylindrical seal ( Figure 26).
• the indium metal taken as an example can be replaced by indium-based alloys such as indium-tin (InSn).
• InSn indium-tin
• the formation of the continuous seal by increasing the temperature to make the indium liquid is between 160 ° C and 175 ° C.
• the hermeticity is then obtained by reflowing the continuous seal on the base of the housing itself showing an adapted metallization.
• the housing 1702 is placed on these balls, bearing, with a support 1701 for a ball or cylinder identical to that of the substrate 1203, as illustrated in FIG. 26.
• a seal is made of ductile material 1801, opposite the intended position of the housing 1802 for encapsulating the electronic components carried by the substrate and a knife shape 1803 is provided at the edge of the housing, a shape intended to sink into the joint thus formed.
• the shape of the edges of the housing 1802 is such that its thickness is less, at its end, than half the average thickness of the housing 1802.
• this Form 1803 is a prismatic shape with an essentially triangular section, the end angle of which is acute, for example of the order of 60 degrees or 1 radian.
• a joint bearing of the conical type with an acute or slightly rounded bearing making it possible in certain cases to avoid the cutting of the joint part.
• the total thickness of the joint in this case may be greater than 10 ⁇ m. In general, the range of the housing should not exceed the thickness of metal.
• the edges of the box 1802 remain pressed into the joint 1801 and is not likely to move parallel to the plane of the substrate 1800. It is observed, in the first line of FIG. 28, that before the assembly of the box 1802 on the substrate 1800, the substrate 1800 carries each electronic component 1805 to be encapsulated and the seal 1801, all around the component 1805. Furthermore, the housing 1802 is made so that its edges have the shape of a knife mentioned above. Then, as shown in the second line of the figure 28, on the left, we position the housing
• FIG. 29 there is an encapsulation of the electronic component identical to that illustrated in FIG. 28, with the exception of the knife 1901 which is carried by the substrate 1900 and the seal 1903, which is carried by the edge of the housing 1902.
• an optical fiber 2006 is carried by a ferrule 2007 having, on its surface facing the substrate 2000, a knife shape 2004 similar to the knife shape of the edges of the housing 2001, which s 'driven into a joint 2005 formed on the substrate 2000.
• the substrate is transparent at the wavelengths considered, opposite the end of the optical fiber.
• the substrate is, for example made of silicon, quartz or Gallium arsenide.
• the housing 2100 is made of transparent material in the spectral light band implemented by the optoelectronic component 2101.
• the housing 2100 is made of quartz, silicon or Arsenide of Gallium). It preferably comprises a window 2102 with a thickness of less than 100 ⁇ m. 5 It can be seen, in FIG.
• a ball 2200 of fusible material for example Indium
• the ball 2200 thus produces a micro -valve.
• the vacuum has been at least partially created in the housing 2202, the ball 2200 is heated to its melting temperature. By capillarity, it then descends into the pipe 2201 and solidifies there, which has the consequence of closing this pipe.
• the encapsulation of the electronic or optoelectronic components is carried out collectively on a single substrate which is then cut to separate the housing-substrate assemblies.

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