Optical system-in-package, method for manufacturing optical system-in-package, and optical module using same

Abstract

The present invention relates to an optical system-in-package and an optical module using same, wherein a laser diode can be packaged together with a silicon photonics chip and an electronic IC in the O-SiP, thereby implementing a short signal line and implementing a structure with integrated optical / electronic elements at a semiconductor package level. The optical system-in-package of the present invention comprises: a mold body having a first surface and a second surface; a laser diode arranged in or outside the mold body; a photonic IC which is molded inside the mold body, receives an optical signal, input from the laser diode through an input waveguide connected to an input side, and has multiple output waveguides connected to an output side; an electronic IC molded in the mold body; a fiber array unit molded in the mold body; and a redistribution layer which is formed on the first surface of the mold body and on which multiple external connection terminals are disposed.

Description

Optical system-in-package, method for manufacturing optical system-in-package, and optical module using the same

[0001] The present invention relates to an optical system-in-package (O-SIP), and more particularly, to an optical system-in-package capable of implementing a short signal line and an integrated optical / electronic device structure at the semiconductor package level by packaging a low-cost single CW laser diode (Continuous Wave Laser Diode) in O-SiP together with a silicon photonics (SiPh) chip and a driving IC, a method for manufacturing the optical system-in-package, and an optical module using the same.

[0002] Semiconductor chips not only perform logic or driver IC functions, but can also produce photodetectors that respond to light or emit light. These optical components are used in a variety of fields, including optical transceivers that provide optical connections between servers, optical modules that transmit video data between TVs and set-top boxes, or between virtual reality (VR) glasses and graphics processing units (GPUs).

[0003] Additionally, other applications of photonic devices include proximity sensors, TOF (Time Of Flight) sensors, and LIDAR (Light Detection And Ranging) that include light-emitting devices.

[0004] Optical devices must be used in conjunction with electronic components that drive or interface with them, thereby converting optical signals into electronic ones. For example, in the field of optical data transmission, optical and electronic components may be used together to create a module that converts optical signals into digital signals. In another example, in the field of optical sensors, components that convert the characteristics of received light into image or depth data may be used in conjunction with optical devices.

[0005] All of the above applications have traditionally used PCBs (printed circuit boards) with wiring patterns formed on their surfaces, mounting multiple chips and interconnecting them via wire bonding. This is typically a Chip-on-Board (CoB) package.

[0006] In addition, instead of the package using the above-mentioned PCB (Printed Circuit Board), a semiconductor package process according to the FOWLP (Fan Out Wafer Level Package) method that does not use a PCB (Printed Circuit Board) can be used to package photoelectric / electric elements in an ultra-thin form without a PCB (Printed Circuit Board) at the wafer level. This is a technology that can improve performance by using a high-precision redistribution layer (RDL) while manufacturing an ultra-thin package.

[0007] When performing optoelectronic packaging using semiconductor packages, the optical path is often perpendicular to the light-emitting device chip, so the optical path is arranged on one side of the package, and external connection terminal pads for external electrical connection are formed on the opposite side of the package. In addition, in these optoelectronic packages, the redistribution layer for connecting the chips molded inside is arranged on one side of the optoelectronic package where the optical path is located.

[0008] Meanwhile, Korean Patent Publication No. 10-2021-0035058 (Patent Document 1) discloses an optical transmission module that optically multiplexes four-channel optical signals of different wavelengths generated from four edge-emitting laser diodes (ELDs) into one single-mode (SM) optical signal through an Arrayed Waveguide Grating (AWG), and then transmits the signal through a single optical fiber. Accordingly, the optical transmission module realizes a wavelength division multiplexer (WDM MUX) of 25 Gbps x 4 channels = 100 Gbps per channel.

[0009] The above optical transmission module can be applied to QSFP (Quad Small Form-factor Pluggable), QSFP+ (Quad Small Form-factor Pluggable Plus), QSFP2B (Quad Small Form-factor Pluggable 2B), etc. as the number of channels increases.

[0010] The optical transmission module of the above patent document 1, when performing a wavelength division multiplexing (WDM) function using an AWG, uses four light-emitting elements such as VCSELs or edge-type light-emitting elements (Edge Emitting Laser Diodes) as photonic ICs, and thus must use expensive laser diodes (LDs).

[0011] In addition, the above patent document 1 must devise a solution to the problem of heat generation along with the increase in package area due to the use of four laser diodes (LD).

[0012] In the past, the method of transmitting an optical signal generated and emitted from an optical module to an optical fiber involved using a groove formed in the optical module, but it is not easy to form a precise groove in the optical module substrate.

[0013] Typically, the outer diameter of a single-mode (SM) optical fiber is 125 μm, and the core diameter of the optical fiber is 10 μm, but the cross-sectional area of ​​the waveguide used to emit the output optical signal from a silicon photonics (SiPh) chip to the outside is 6.7 × 6.7 μm in width × height, and the core of the waveguide is set to 105 × 6.7 nm.

[0014] As a result, optical alignment is difficult because the cores of multiple waveguides that emit multiple optical signals of multiple wavelengths generated from a conventional silicon photonics (SiPh) chip have a significantly large difference in diameter from the cores of optical fibers.

[0015] It is possible to implement an integrated circuit (IC) inside a silicon photonics (SiPh) chip, a type of photonic IC, but the micropattern for this and the pattern for silicon photonics (SiPh) have a large difference in area, so it is not cost-effective to integrate them on a single substrate.

[0016] In most cases, a separate external electronic IC (EIC) is used to drive a modulator or a photodiode (PD).

[0017] Therefore, the problem to be solved by the present invention is to package a low-cost single CW laser (Continuous Wave Laser) as a photonic IC inside O-SiP together with a silicon photonics (SiPh) chip and an electronic IC (EIC) to implement a short signal line and a structure in which optical / electronic elements are integrated at the semiconductor package level.

[0018] The present invention has been made to solve the above problems, and its purpose is to provide an optical system-in-package, a method for manufacturing the optical system-in-package, and an optical module using the same, which can realize a wavelength division multiplexer (WDM MUX) of 100 Gbps or more while using a low-cost single CW laser diode (Continuous Wave Laser Diode) and a silicon photonics (SiPh) chip as a photonic IC instead of a plurality of expensive short-wavelength laser diodes.

[0019] Another object of the present invention is to provide an optical system-in-package, a method for manufacturing an optical system-in-package, and an optical module using the same, which can easily achieve precise alignment between an optical fiber and a waveguide (core) of a silicon photonics (SiPh) chip by integrating a fiber array unit (FAU) inside the package at a wafer level using a semiconductor package method according to the FOWLP (Fan Out Wafer Level Package) method when a silicon photonics (SiPh) chip as a photonic IC is provided inside the package and lateral optical coupling is performed in the horizontal direction with the package body.

[0020] An optical system-in-package (O-SIP) according to one embodiment of the present invention is characterized by including: a mold body having first and second surfaces that are flat at the top and bottom; a laser diode disposed inside or outside the mold body to output an optical signal; a photonic IC molded inside the mold body so that a conductive stud connected to a terminal pad on the first surface is exposed and receives an optical signal input from the laser diode through an input waveguide connected to an input side and having a plurality of output waveguides connected to an output side; an electronic IC molded inside the mold body so that a conductive stud connected to the terminal pad on the first surface is exposed and drives or interfaces the laser diode and the photonic IC; a fiber array unit (FAU) molded inside the mold body and outputting a plurality of optical signals output through the plurality of output waveguides of the photonic IC to a plurality of optical fibers; and a redistribution layer formed on the first surface of the mold body and having a plurality of external connection terminals disposed thereon for interconnecting the laser diode, the photonic IC, and the electronic IC and electrically connecting them to the outside.

[0021] The above photonic IC may be a silicon photonics (SiPh) chip that guides optical signals of all wavelengths output from the laser diode to an input waveguide, modulates and separates them into each wavelength, and outputs the optical signals of each obtained wavelength band through a plurality of output waveguides.

[0022] The above fiber array unit (FAU) has a plurality of waveguides optically aligned with a plurality of output waveguides of the photonic IC at the front of the body, and a plurality of optical fiber insertion holes connected to the plurality of waveguides, and when an optical fiber is inserted into the optical fiber insertion hole, the core of the optical fiber can be optically aligned with the plurality of output waveguides of the photonic IC.

[0023] The above fiber array unit (FAU) has a plurality of optical fiber insertion holes penetrating the body, and when an optical fiber is inserted into the optical fiber insertion holes, the core of the optical fiber can be optically aligned with a plurality of output waveguides of the photonic IC.

[0024] The above fiber array unit (FAU) has a plurality of waveguides formed by penetrating the body, and the plurality of waveguides can be optically aligned with a plurality of output waveguides of the photonic IC.

[0025] An optical system-in-package (O-SIP) according to the present invention may further include an output waveguide having a loopback structure for returning laser light input from the fiber array unit (FAU) to the fiber array unit (FAU) on the outside of a plurality of output waveguides provided in the photonic IC.

[0026] The above fiber array unit (FAU) may further include a plurality of optical fiber receiving grooves on the upper portion of the fiber array unit (FAU), each of which can receive a portion of the plurality of optical fibers; and an optical fiber protection cover installed on the upper portion of the fiber array unit (FAU) to prevent the plurality of optical fibers installed in the plurality of optical fiber receiving grooves from falling out.

[0027] According to another embodiment of the present invention, an optical system-in-package (O-SIP) is characterized by including: a mold body having first and second surfaces that are flat on the top and bottom; a photonic IC molded inside the mold body on the first surface and having an input waveguide connected to an input side and a plurality of output waveguides connected to an output side; an electronic IC molded inside the mold body so that a conductive stud connected to a terminal pad on the first surface is exposed and driving or interfacing the photonic IC; and a fiber array unit (FAU) molded inside the mold body and outputting a plurality of optical signals output through the plurality of output waveguides of the photonic IC to a plurality of optical fibers.

[0028] An optical system-in-package (O-SIP) according to the present invention further includes: a laser diode disposed inside or outside the mold body to output an optical signal to an input waveguide of the photonic IC; and a redistribution layer formed on a first surface of the mold body and having a plurality of external connection terminals disposed thereon for interconnecting the laser diode, the photonic IC, and the electronic IC while electrically connecting them to the outside; wherein the photonic IC may be a silicon photonics (SiPh) chip that guides optical signals of all wavelengths output from the laser diode to the input waveguide, modulates them into respective wavelengths, separates them, and outputs the obtained optical signals of each wavelength band to the fiber array unit (FAU) through the plurality of output waveguides.

[0029] An optical system-in-package (O-SIP) according to the present invention further includes an input-side fiber array unit (FAU) having an optical fiber insertion hole into which an optical fiber connected to the laser diode can be detachably coupled when the laser diode is disposed outside the mold body, and the input-side fiber array unit (FAU) can be formed by connecting a waveguide optically aligned with an input waveguide of the silicon photonics (SiPh) chip through the optical fiber insertion hole.

[0030] According to another embodiment of the present invention, an optical module is an optical system-in-package (O-SIP) in which a laser diode, a silicon photonics (SiPh) chip, an electronic IC, and a fiber array unit (FAU) are molded inside a mold body having flat first and second surfaces at the upper and lower portions, and the silicon photonics (SiPh) chip processes an optical signal generated from the laser diode and transmits the optical signal of each wavelength band to a plurality of optical fibers coupled to the fiber array unit (FAU); And a main printed circuit board (PCB) on which the optical system-in-package (O-SIP) is mounted on the upper surface and on which a plurality of electronic components for performing transmission and reception control for the optical system-in-package (O-SIP) are mounted on the lower surface; wherein the silicon photonics (SiPh) chip guides optical signals of all wavelengths output from the laser diode to an input waveguide, modulates and separates them into each wavelength, and outputs the obtained optical signals of each wavelength band to the fiber array unit (FAU) through a plurality of output waveguides.

[0031] The above optical system-in-package (O-SIP) has a fiber array unit (FAU) in the front of the body, a plurality of waveguides optically aligned with a plurality of output waveguides of the silicon photonics (SiPh) chip, and a plurality of optical fiber insertion holes connected to the plurality of waveguides, and when an optical fiber is inserted into the optical fiber insertion hole, the core of the optical fiber can be optically aligned with a plurality of output waveguides of the silicon photonics (SiPh) chip.

[0032] A method for manufacturing an optical system-in-package (O-SIP) according to the present invention comprises the steps of: performing optical alignment with an output waveguide of a photonic IC while inserting an optical fiber into an optical fiber insertion hole of a fiber array unit (FAU); fixing the photonic IC and the fiber array unit (FAU) using an adhesive when the optical alignment is achieved; separating the optical fiber inserted into the optical fiber insertion hole of the fiber array unit (FAU) and attaching a protective wall to the rear end of the fiber array unit (FAU) to prevent the optical fiber insertion hole from being blocked; attaching a plurality of conductive studs to a plurality of terminal pads of each of a laser diode, a photonic IC, and an electronic IC, and attaching first and second heat sinks to lower surfaces of the photonic IC and the electronic IC; The method is characterized by comprising the steps of: attaching the laser diode, the photonic IC and the electronic IC to which the fiber array unit is attached to the adhesive layer of the molding tape at preset positions using a flip chip process; forming a molding layer on the upper part of the molding tape with an epoxy mold compound (EMC) and, after curing, flattening the surface so that the upper ends of the plurality of conductive studs are exposed; forming a redistribution layer on the upper part of the flattened mold body; and dicing and separating the die chip from the wafer, and then cutting the diced optical system-in-package (O-SIP) along a cutting line so that the optical fiber insertion hole of the fiber array unit is exposed and polishing the diced optical system-in-package (O-SIP) so that the optical fiber coupling hole is exposed.

[0033] The above optical system-in-package (O-SIP) can be manufactured by packaging using the face-up FOWLP method.

[0034] As described above, in the present invention, a low-cost single CW laser diode is packaged in O-SiP together with a silicon photonics (SiPh) chip and an external electronic IC (EIC), thereby enabling implementation of a short signal line and an integrated structure of optical / electronic elements at the semiconductor package level.

[0035] In the present invention, a wavelength division multiplexer (WDM MUX) of 100 Gbps or more can be realized by using a low-cost single CW laser (Continuous Wave Laser) diode and a silicon photonics (SiPh) chip instead of expensive multiple short-wavelength laser diodes.

[0036] The above silicon photonics (SiPh) chip guides optical signals of all wavelengths output from a low-cost single CW laser diode into a waveguide of the silicon photonics (SiPh) chip, modulates and separates them into each wavelength through a micro ring modulator (MRM), and outputs the optical signals of each wavelength band obtained using multiple optical fibers.

[0037] In addition, in the present invention, when a fiber array unit (FAU) in which a plurality of optical fibers are assembled on a silicon photonics (SiPh) chip is used to perform lateral optical coupling in the horizontal direction with the package body, an optical system-in-package (O-SIP) can be packaged at the wafer level using a semiconductor package method according to the FOWLP (Fan Out Wafer Level Package) method.

[0038] In order to solve the above problem, the present invention uses a semiconductor package method according to the FOWLP (Fan Out Wafer Level Package) method to integrate a fiber array unit (FAU) into the package at the wafer level when a silicon photonics (SiPh) chip is provided inside the package and lateral optical coupling is performed in the horizontal direction with the package body, thereby easily achieving precise alignment between an optical fiber and a waveguide (core) of a silicon photonics (SiPh) chip.

[0039] FIG. 1 is a cross-sectional view of an optical system-in-package (O-SIP) using semiconductor packaging according to a first embodiment of the present invention.

[0040] FIG. 2 is a plan view of an optical system-in-package (O-SIP) using a silicon photonics (SiPh) chip as a photonic IC in FIG. 1.

[0041] FIG. 3a is a plan view showing an integrated laser system (ILS) having a continuous wave laser (CW laser) built into an optical system-in-package (O-SIP) package having a silicon photonics (SiPh) chip, an electronic IC, and a fiber array unit (FAU) built therein according to a first embodiment of the present invention.

[0042] FIG. 3b is a plan view showing an external laser system (ELS) in which a continuous wave laser (CW laser) is detachably coupled to the outside of an optical system-in-package (O-SIP) having a silicon photonics (SiPh) chip, an electronic IC, and a fiber array unit (FAU) built in according to a second embodiment of the present invention.

[0043] FIG. 3c is a plan view showing an optical system-in-package (O-SIP) having a fiber array unit (FAU) having a through hole formed inside the body for coupling optical fibers according to a first embodiment of the present invention.

[0044] FIG. 3d is a plan view showing an optical system-in-package (O-SIP) having a fiber array unit (FAU) having a waveguide and a fiber core of silicon photonics (SiPh) and a waveguide for optical alignment within a body according to a first embodiment of the present invention.

[0045] FIGS. 4A to 4D are process diagrams showing a manufacturing method for manufacturing an optical system-in-package (O-SIP) according to a first embodiment of the present invention at a wafer level using a semiconductor package method according to the FOWLP (Fan Out Wafer Level Package) method.

[0046] FIG. 4f and FIG. 4g are cross-sectional views showing an optical module in which an optical system-in-package (O-SIP) according to a first embodiment of the present invention is mounted on a main PCB, and a cross-sectional view showing an optical module in which a ferrule fiber array (FA) is coupled to a fiber array unit (FAU).

[0047] FIG. 5a and FIG. 5b are side and cross-sectional views, respectively, of an optical system-in-package (O-SIP) for resolving a problem in which the height from the fiber array unit (FAU) core to the FAU surface is insufficient due to a large diameter of the optical fiber.

[0048] FIG. 6a and FIG. 6b are side and cross-sectional views, respectively, of an optical system-in-package (O-SIP) for resolving a problem in which the height from the fiber array unit (FAU) core to the FAU surface is insufficient due to a large diameter of the optical fiber.

[0049] FIG. 7a and FIG. 7b are side and cross-sectional views, respectively, of an optical system-in-package (O-SIP) for resolving a problem in which the height from the fiber array unit (FAU) core to the FAU surface is insufficient due to a large diameter of the optical fiber.

[0050] Hereinafter, a preferred embodiment according to the present invention will be described with reference to the attached drawings.

[0051] In this process, the size and shape of the components depicted in the drawing may be exaggerated for clarity and convenience of explanation.

[0052] In general, semiconductor packages are required to perform four main roles: mechanical protection, electrical connection, mechanical connection, and heat dissipation.

[0053] Semiconductor packages protect semiconductor chips / elements from external mechanical and chemical shocks by wrapping them in packaging materials such as EMC (Epoxy Mold Compound).

[0054] Semiconductor packages physically and electrically connect multiple molded chips to a system. Electrically, they must connect the chips to the system, supplying power to the chips and providing input and output signals to enable their desired functions. Furthermore, mechanically, they must be properly connected to ensure the chips remain firmly attached to the system throughout their lifespan.

[0055] At the same time, heat generated from chips and components must be quickly dissipated. When semiconductor products operate, current flows, and this current inevitably creates resistance and, consequently, heat.

[0056] Semiconductor packages completely enclose the chip. If the package fails to dissipate heat effectively, the chip may overheat, causing the temperature of the molded components or chips within it to rise above their operating temperature, ultimately leading to the failure of the components or chips. Therefore, the semiconductor package's role in effectively dissipating heat is essential. As semiconductor products increase in speed and functionality, the importance of the package's cooling function is growing.

[0057] A System in Package (SiP) stacks or arranges multiple chips within a single package to provide a single, independent function. Typically, a SiP is a complete system, comprising multiple chips that include a signal processing unit, such as a microprocessor, and multiple memories.

[0058] The present invention relates to an optical system-in-package (OSP) equipped in an optical transceiver or the like, which can be mounted on a main PCB to form an optical module, and the optical module can be built into the optical transceiver.

[0059] The above main PCB may be largely equipped with an LDD (laser diode driver) and CDR (clock data recovery) for the optical transmission sub-assembly (TOSA; Transmitter Optical Sub-Assembly), a TIA (transimpedance amplifier) / LA (limiting amplifier) ​​and CDR for the optical reception sub-assembly (ROSA; Receiver Optical Sub-Assembly), and an MCU (microcontroller unit) that performs overall transmission and reception control of the optical transceiver.

[0060] The above main PCB is equipped with an ADC (Analog-to-Digital Convertor) and a DAC (Digital-to-Analog Convertor), and can be configured to digitally process signals by an MCU (Microcontroller Unit) and an FPGA (Field Programmable Gate Array), or can be configured with a DSP (Digital Signal Processing Device) and a driver to drive a TOSA (Optical Transmission Subassembly) and a ROSA (Optical Reception Subassembly). In addition, the above main PCB can be configured in various other ways.

[0061] Silicon photonics (SiPh), a type of photonic IC, forms waveguides on silicon-on-insulator (SOI) substrates, enabling the integration of optical components with diverse functions. Representative examples include modulators, microring modulators, delay lines, silicon cavities, phase shifters, fiber couplers, and beam splitters.

[0062] For example, modulation of optical signals for optical transceivers can be implemented using a modulator made of silicon photonics (SiPh). In this case, a continuous wave laser (CW laser) is used to inject a constant beam of light into the waveguide of a silicon photonics chip (Si Photonics Chip), modulate the optical signal through the modulator of the Si Photonics chip, and then feed it into an optical fiber for transmission.

[0063] In addition, by modulating and separating each wavelength through a micro ring modulator (MRM) implemented with silicon photonics (SiPh; Si Photonics), it is possible to implement MUX (Multiplexing) and DEMUX (Demultiplexing) for wavelength division multiplexing (WDM; Wavelength Division Multiplexing), and to manufacture a transmitter (Tx) and receiver (Rx) engine for an optical transceiver using this.

[0064] The laser for the light source can be provided as an external laser source outside the package to input a CW laser (Continuous Wave Laser) into the silicon photonics (SiPh) chip, or can be integrated into the package to input a CW laser (Continuous Wave Laser) into the silicon photonics (SiPh) chip.

[0065] Moreover, in the present invention, a fiber array unit (FAU) can be integrally provided inside the package to input / output an optical signal from silicon photonics (SiPh; Si Photonics) as a photonic IC.

[0066] The attached drawing 1 is a cross-sectional view of an optical system-in-package (O-SIP) using semiconductor packaging according to a first embodiment of the present invention, and drawing 2 is a plan view of an optical system-in-package (O-SIP) using a silicon photonics (SiPh) chip as a photonic IC in drawing 1.

[0067] Referring to FIG. 1 below, an optical system-in-package (O-SIP) using semiconductor packaging according to a first embodiment of the present invention is described.

[0068] An O-SIP (100) according to a first embodiment of the present invention includes a photonic IC (PIC; Photonic Integrated Circuit) (130) and an electronic IC (EIC; Electronic Integrated Circuit) (140) inside a mold body (110), and the mold body (110) has a first surface (upper surface) (112) and a second surface (lower surface) (114) that face each other and are preferably flat. A first redistribution layer (RDL) (120) for electrically connecting the photonic IC (130) and the electronic IC (140) to each other is formed on the first surface (upper surface) (112) of the mold body (110), and a plurality of external connection terminals (161) for electrical external connection of the package are included on the upper portion of the first redistribution layer (RDL) (120).

[0069] According to the first embodiment of the present invention, the O-SIP (100) integrates a photonic IC (130) and an electronic IC (140) without wire-bonding by using a flip chip package technology, and at the same time, integrates elements without using a substrate (PCB) and increases the number of input / output (I / O) terminals by pulling the input / output terminals outward, a so-called FOWLP (Fan Out Wafer Level Package) method, thereby completely resolving the height tolerance due to wiring between elements and implementing a slim O-SIP (100).

[0070] The above O-SIP (100) is a type of SiP (System In Package) technology that integrates photonic ICs (130) and electronic ICs (140) in a flip chip form without using a substrate such as a PCB, and configures a mold body (110) by packaging using a sealing material such as an epoxy mold compound (EMC) to fix the chip (die).

[0071] As a result, the mold body (110) safely protects the light engine module, which is packaged after integration, from impact. The O-SIP (100) having a photonic IC (130) and an electronic IC (140) inside the mold body (110) can constitute a light engine module.

[0072] In addition, the O-SIP (100) can be obtained as a single semiconductor package type by performing a manufacturing process using a semiconductor process on a wafer basis, and then integrally forming a first rewiring layer (120) including a plurality of external connection terminals (161) on the first surface (upper surface) (112) of the package, and then individually separating the first and second layers through a dicing process.

[0073] The above photonic IC (130) and electronic IC (140) are molded inside the package, and an external connection terminal (161) on which a solder ball for electrical connection is mounted is arranged on the first surface (upper surface) (112) of the mold body (110).

[0074] The above photonic IC (130) is an integrated circuit (IC) that performs optical signal processing and can play a role in converting an optical signal into an electrical signal or converting an electrical signal into an optical signal.

[0075] The above photonic IC (PIC; Photonic Integrated Circuit) (130) is a semiconductor chip that is capable of generating, receiving, or processing an optical signal and is composed of the following main components.

[0076] First, there is an electrical terminal pad (Electrical PAD) for electrical signal connection, which can be located on the top (first side), bottom (second side), or both sides of the PIC (130) chip. For example, in data communication and optical sensor systems, an Electrical PAD is required to effectively connect the PIC (130) chip to other circuits.

[0077] Second, there is an optical port part that can emit light to the outside or receive light from the outside, which can be located on the side (edge ​​surface), top, or bottom of the PIC (130) chip. If the optical port is located on the side of the PIC (130) chip, it is defined as having a lateral optical path, and if it is located on the top or bottom, it is defined as having a vertical optical path. For example, a lateral optical path can be easily connected to an optical fiber, and a vertical optical path can be utilized in optical sensor or display applications.

[0078] Third, it may include an optical signal generation and processing unit capable of generating or processing an optical signal internally.

[0079] The PIC (130) has a structure capable of outputting optical energy or an optical signal to the outside. At this time, it can be designed so that light is output from the semiconductor surface, and an anti-reflection coating can be applied to minimize surface reflection. For example, light generated from an internal LED structure or a VCSEL (Vertical-Cavity Surface-Emitting Laser) can be output through the surface of the PIC (130). In addition, when an optical waveguide exists inside the PIC (130), light can be output directly from the end of the optical waveguide, or additional structures such as a lens, reflector, or grating structure for adjusting the optical path can be included. For example, by using a grating structure inside the PIC (130), light can be adjusted to be emitted to the outside at a specific angle.

[0080] The PIC (130) also includes a function of receiving an optical signal from the outside. This can be implemented by absorbing light on the semiconductor surface, and an anti-reflection coating can be applied to reduce surface reflection. For example, light incident through the surface of the PIC (130) can be transmitted to the PN junction of a photodiode and converted into an electrical signal. An avalanche photodiode (APD) can be used to improve the optical reception performance, which is useful for increasing the light detection sensitivity. In addition, the optical input can be transmitted through an optical waveguide within the PIC (130). For example, a grating coupler can be used for efficient coupling when transmitting a signal from an optical fiber (350) to the optical waveguide within the PIC (130).

[0081] The PIC (130) may include a part that generates an optical signal, which is implemented by converting electrical energy into optical energy through a semiconductor junction. For example, a VCSEL (Vertical-Cavity Surface-Emitting Laser), a DFB laser diode (Distributed Feedback Laser Diode), a FP laser diode (Fabry-Perot Laser Diode), an EML (Electro-Absorption Modulated Laser), an LED (Light-Emitting Diode), etc. may be used as a light source within the PIC (130). At this time, mainly III-V or II-VI group semiconductor materials are used. For example, a GaAs (Gallium Arsenide) based VCSEL is widely used in high-speed data communication, and an InP (Indium Phosphide) based DFB laser is used to provide a light source in an optical communication network.

[0082] The generated optical signal can be output to the outside of the PIC (130) or transmitted to the internal optical signal processing unit (202). If the optical signal is not generated within the PIC (130), an optical signal input from the outside can be transmitted to the optical signal processing unit (202). In addition, the generated optical signal can have a single wavelength or multiple wavelengths, and if multiple wavelengths are utilized, various applications are possible in conjunction with a broadband light source or WDM (Wavelength Division Multiplexing) technology.

[0083] The optical signal processing unit (202) within the PIC (130) processes optical signals input from the outside or inside. This optical signal processing may include various functions, such as the following.

[0084] Optical modulation is a method of modulating an optical signal, direct modulation is a method of changing the optical output of a laser by directly modulating the current, and external modulation is a method of maintaining the optical output constant and modulating it with an external electrical signal.

[0085] Optical detection is a technology that converts an optical signal into an electrical signal. The photodiode (PD) is used as a basic detection element, the PIN photodiode provides low noise and fast response speed, and the APD (Avalanche Photodiode) provides high sensitivity through an internal electronic amplification function.

[0086] Optical amplification is a technology that increases the intensity of a signal. A semiconductor optical amplifier (SOA) directly amplifies a signal light based on a semiconductor, an erbium-doped fiber amplifier (EDFA) performs amplification by utilizing erbium ions doped in an optical fiber, and a lamp / diode pumping amplifier amplifies a signal using an optical pumping method.

[0087] Optical filtering is a technology that selectively transmits only specific optical signals. An optical bandpass filter passes only a specific frequency band, a wavelength selective filter selectively transmits only specific wavelengths, and wavelength multiplexing / demultiplexing (WDM / DWDM, CWDM) processes signals by combining or separating multiple wavelengths.

[0088] Optical Multiplexing & Demultiplexing is a technology that divides or combines one optical channel into multiple signals. Wavelength Division Multiplexing (WDM) multiplexes optical signals of different wavelengths onto a single optical fiber, Time Division Multiplexing (TDM) multiplexes signals at time intervals, and Polarization Division Multiplexing (PDM) multiplexes signals using different polarization states.

[0089] Optical Switching & Routing is a technology that controls the path of an optical signal. An optical switch changes the path of a signal, an optical wavelength router transmits a signal of a specific wavelength to a desired path, and optical burst switching (OBS) is a switching technology that transmits an optical signal in packet units.

[0090] Optical signal processing is a technology that processes signals optically, optical logic operations perform logic operations using light, optical FFT (Fourier Transform) and signal conversion process signals using optical Fourier transform, and optical computation and artificial intelligence optical computing are technologies that perform data processing and calculations using light.

[0091] Optical wavelength change is a technology that can change the wavelength of input light into various other wavelengths through structures such as frequency combs.

[0092] As a technology for detecting the surrounding environment, distributed optical fiber sensors use optical fibers to detect changes in a wide area, laser interferometer sensors perform precise sensing using the laser interference effect, and LIDAR (Light Detection and Ranging) is a technology that uses lasers to measure distance and the location of objects.

[0093] The above photonic IC (PIC) (130) may be, for example, formed of a silicon photonics (SiPh) (200) chip (see FIG. 2) having input and output waveguides (210, 240) on one side and the other side of an optical signal processing unit (202).

[0094] The above optical signal processing unit (202) may be formed of an optical integrated circuit (IC) that performs functions such as a modulator, a beam splitter, and wavelength division multiplexing (WDM).

[0095] The above silicon photonics (SiPh) (200) is a silicon-based optical integrated circuit technology that can be mass-produced using a CMOS process and enables cost-effective PIC implementation. The SiPh-based PIC (130) includes elements such as an optical waveguide, an optical modulator, a photodetector, an integrated optical coupler, and an integrated optical device.

[0096] Silicon-based optical waveguides can efficiently transmit optical signals by utilizing the high refractive index contrast difference, and a Mach-Zehnder Interferometer (MZI) or ring resonator-based modulator that modulates the phase and intensity of the optical signal through an electric field or carrier injection can be used. In addition, a photodetector with a silicon-compatible Ge-on-Si structure can be included, and a grating coupler can be utilized for efficient optical coupling between the optical fiber (350) and the PIC (130). While conventional SiPh uses an external light source, recent InP-based hybrid integration methods can also include a laser element.

[0097] SiPh(200) chips are not necessarily implemented using only silicon (Si)-based optical waveguides. Various materials can be used as optical waveguides, and the choice depends on the specific application. Silicon oxynitride (SiON) optical waveguides, made of silicon oxynitride, have a lower refractive index than silicon, yet offer lower optical loss and a wide wavelength range, making them useful in biosensing and optical filtering applications.

[0098] SiN (Silicon Nitride) optical waveguides have a wide transmission band from 400 nm to 2.5 μm and provide low optical loss, making them widely used in high-power laser systems, optical integrated circuits, and quantum optics applications. Ge-on-Si (Germanium-on-Silicon) optical waveguides exhibit high photoelectric conversion efficiency in the infrared band (greater than 1.55 μm) and are used in photodetectors and infrared sensor applications. Furthermore, SiC (Silicon Carbide)-based optical waveguides, which have high thermal conductivity and durability, are suitable for optical systems operating in extreme environments, and Al (Al)-based optical waveguides offer high transparency and low loss, which can be utilized in optical amplifiers and quantum optics applications.

[0099] To achieve higher bandwidth and performance, optical waveguides based on lithium niobate (LiNbO3) or those utilizing plasmonic structures are being studied. LiNbO3 is a material with excellent nonlinear optical properties and wide electro-optical coefficients, and is being utilized as high-speed optical modulators and optical switching devices. In particular, it can provide higher speeds (over 100 GHz) and lower insertion loss than conventional silicon optical waveguide-based modulators, playing a crucial role in next-generation optical communication systems. Recent research is developing a hybrid Si-LiNbO3 structure to realize high-performance optical modulators while maintaining compatibility with existing CMOS processes. LiNbO3-based optical waveguides are attracting attention as a key technology for ultra-high-speed data center networks, quantum optical communications, and optical AI accelerator applications.

[0100] Plasmonic waveguides are a technology that can transmit optical signals in nanometer-scale ultra-small structures by utilizing metal-insulator-metal (MIM) or metal-insulator-semiconductor (MIS) structures. Plasmonic structures can focus light into a smaller area than conventional silicon waveguides, enabling the creation of extremely small, ultra-fast optical modulators and optical switches. Plasmonic-based optical devices have great potential for use in terahertz (THz)-band optical communications, ultra-high-speed signal processing, and integrated optical computing applications. Current research is developing ways to integrate plasmonic structures with CMOS processes so that they can be used with silicon photonics (SiPh)-based systems.

[0101] In the present invention, all optical integrated circuits containing these various materials and structures are considered PICs (Photonic Integrated Circuits). PICs (130) that integrate these diverse functions can be utilized in various applications such as optical communications, optical sensing, medical care, and data centers.

[0102] In addition, the O-SIP (100) according to the first embodiment of the present invention can be equipped with a light-emitting element, such as a low-cost single CW (Continuous Wave) laser diode (LD) (190), on the input side of a silicon photonics (SiPh) (200) chip, as shown in FIGS. 1 and 2, inside the mold body (110).

[0103] The optical signal processing unit (202) provided in the silicon photonics (SiPh) (200) chip illustrated in FIG. 2 as the photonic IC (130) can, for example, guide optical signals of all wavelengths output from a low-cost single CW laser diode (190) to an input waveguide (210) of the silicon photonics (SiPh) (200) chip, then modulate and separate the optical signals into respective wavelengths through a micro ring modulator (MRM), and then output a single mode (SM) optical signal from an output waveguide (240) by wavelength division multiplexing (WDM) the obtained plurality of optical signals of each wavelength band using a pulse amplitude modulation (PAM) method.

[0104] In addition, the silicon photonics (SiPh) (200) can be modulated into each wavelength in the optical signal processing unit (202) and separated, and multiple optical signals of each wavelength band obtained can be transmitted to the outside through multiple optical fibers (350).

[0105] In this case, in the present invention, a plurality of optical fibers (350) are assembled inside a housing body (310) to form a fiber array unit (FAU; Fiber Array Unit) (300), and can be integrally packaged inside a mold body (110) of an O-SIP (100) together with the silicon photonics (SiPh) (200) chip.

[0106] In the present invention, when performing lateral optical coupling with the package body of an optical system-in-package (O-SIP) (100) in the horizontal direction, as illustrated in FIGS. 4a to 4f described below, a silicon photonics (SiPh) (200) chip is provided inside the package, and a semiconductor package method according to the FOWLP (Fan Out Wafer Level Package) method is used to integrate a fiber array unit (FAU; Fiber Array Unit) (300) inside the package at the wafer level, thereby easily achieving precise optical axis alignment between the core (350a) of the optical fiber (350) and the output waveguide (240) of the silicon photonics (SiPh) (200) chip.

[0107] In the case of the O-SIP (100) as a transmitter (Tx) of an optical module (500), the silicon photonics (SiPh) (200) chip modulates and separates the light incident on the input waveguide (210) into each wavelength within the optical signal processing unit (202), and transmits the obtained multiple optical signals of each wavelength band to the outside through multiple optical fibers (350) provided in the fiber array unit (FAU) (300).

[0108] In the case where the O-SIP (100) is a receiving unit (Rx) of an optical module (500), the optical signal processing unit (202) of the silicon photonics (SiPh) (200) chip divides a single mode (SM; Single Mode) optical signal incident from the outside into each wavelength through a demultiplexing (DEMUX) structure. In this case, a photodiode (PD) may be integrated into the silicon photonics (SiPh) (200), or the optical signal may be output to a photodiode (PD) installed externally.

[0109] Moreover, the O-SIP (100) according to the first embodiment of the present invention may additionally include a signal processing device as a circuit or integrated circuit (IC) that provides additional functions to a photodetector such as a photodiode (PD) or an avalanche photodiode (APD) or that is responsible for signal processing within the mold body (110).

[0110] The above electronic IC (140) drives or interfaces the photonic IC (130), and may include an integrated circuit (IC) that performs electrical signal processing, amplifies / converts an electrical signal received from the photonic IC (130), etc., and may be composed of individual ICs and integrated ICs that perform laser diode driver (LD Driver) IC, modulator driver (Modulator Driver), CDR (Clock Data Recovery), equalizer, TIA (TransImpedance Amplifier), I2C communication, DSP (Digital Signal Processing), etc.

[0111] In addition, the O-SIP (100) according to the first embodiment of the present invention may further include elements having various functions such as a memory, a logic processor, and an analog driver.

[0112] In this case, various materials including semiconductor materials such as GaAs, InGaAs, Si, SiN, Glass, Quartz, and SiON can be used as elements for the photonic IC (130), and various semiconductor materials such as Si, SiC, and SiGe can also be used as elements for the electronic IC (140). In order to mold the photonic IC (130) and the electronic IC (140), an encapsulating material such as an epoxy mold compound (EMC) or an epoxy resin can be used, and in the molding step, multiple cells can be molded at the wafer and panel levels at once.

[0113] A first rewiring layer (120) is formed on the second surface (upper surface) (114) of the mold body (110) formed by the above-mentioned sealing material, and the first rewiring layer (120) includes an external connection terminal (161) of the package.

[0114] In order to form an insulating film for the first wiring layer (120), various materials such as polyimide, PMMA (poly(methylmethacrylate)), benzocyclobutene (BCB), silicon oxide (SiO2), acrylic, and epoxy may be used, and a photolithography process may be used to form a wiring layer pattern.

[0115] In this case, the material of the wiring layer itself can act as a developable PR (Photoresist), and the wiring layer can be etched after additional PR coating. After the insulating film is created, a process of depositing a metal is performed, and the metal used in the first rewiring layer (120) can be formed of various metal materials such as Cu, Al, Au, Ag, or compounds thereof.

[0116] The first wiring layer (120) illustrated in FIG. 1 is formed by connecting the terminal pads (131, 132, 141, 142) of each of the photonic IC (130) and the electronic IC (140) exposed to the first surface (upper surface) (112) of the mold body (110) to form a plurality of external connection terminals (161) in a fan-out form for interconnection between the photonic IC (130) and the electronic IC (140) and simultaneously for connection with the outside of the O-SIP (100) using a plurality of connecting wires (126) made of metal formed inside the insulating layer in two stages, and connecting the terminal pads (131, 132, 141, 142) and the external connection terminals (161) on the upper part of the package.

[0117] The external connection terminal (161) created on the first rewiring layer (120) can be manufactured by exposing the metal surface of the first rewiring layer (120) directly to the outside, like the LGA (Land Grid Array) type, or by mounting solder balls on the top of the package, like the BGA (Ball Grid Array) type illustrated in FIG. 1.

[0118] In addition, the O-SIP (100) may have a redistribution layer (RDL) formed on both the first surface (upper surface) (112) and the second surface (lower surface) (114) of the mold body (110), or may be formed on either the first surface (upper surface) (112) or the second surface (lower surface) (114).

[0119] Moreover, the O-SIP (100) according to the first embodiment of the present invention may further include a second redistribution layer (RDL) (121) on the second surface (lower surface) (114) of the mold body (110), and the second redistribution layer (RDL) (121) may be electrically connected to the first redistribution layer (RDL) (120) disposed on the first surface (upper surface) (112) by using a through-hole filled with a conductive material, a through-conductive vertical via (150) or other equivalent having this function, which penetrates from the first surface (upper surface) (112) of the mold body (110) to the second surface (lower surface) (114).

[0120] The connecting wire (129) provided inside the insulating layer of the second redistribution layer (RDL) (121) can be manufactured by mounting solder balls on the bottom of the package, similar to the first redistribution layer (RDL) (120), such as an LGA (Land Grid Array) type or BGA (Ball Grid Array) type in which an external connection terminal (162) is exposed to the outside.

[0121] Additionally, a third redistribution layer (RDL) (122) may be added to the second surface (lower surface) (114) of the mold body (110) and arranged at a distance from the second redistribution layer (RDL) (121).

[0122] The third redistribution layer (RDL) (122) may be electrically connected directly to the second redistribution layer (RDL) (121) or may be electrically connected to the first redistribution layer (RDL) (120) through another through-conductive via formed through the mold body (110).

[0123] The third redistribution layer (RDL) (122) has a connection wire (129) inside the insulation layer similar to the second redistribution layer (RDL) (121), and an external connection terminal (162) can be formed on the connection wire (129) by mounting a BGA (Ball Grid Array) type solder ball on the bottom of the package.

[0124] Moreover, first and second heat sinks (170, 171) made of, for example, a Cu pad or a heat dissipation material are attached to the lower surfaces of the photonic IC (PIC) (130) and the electronic IC (EIC) (140), and the lower surfaces of the first and second heat sinks (170, 171) are exposed to the outside.

[0125] In addition, the O-SIP (100) according to the first embodiment of the present invention can attach a plurality of conductive studs (135) to a plurality of terminal pads (191, 182, 131, 132, 141, 142) of the CW laser diode (LD) (190), the photonic IC (PIC) (130), and the electronic IC (EIC) (140).

[0126] In this case, the conductive stud (135) may be made of a metal material having excellent conductivity, such as Cu, Au, W (tungsten), or a stud using an alloy thereof.

[0127] In this case, the molding process according to the FOWLP (Fan Out Wafer Level Package) method may be performed by attaching the CW laser diode (LD) (190), photonic IC (PIC) (130), electronic IC (EIC) (140), and fiber array unit (FAU; Fiber Array Unit) (300) to preset positions using a molding tape having an adhesive layer (or release tape) formed on one side of a molding frame through a flip chip process, and then proceeding in one of the face-down FOWLP and face-up FOWLP methods.

[0128] The O-SIP (100) according to the first embodiment illustrated in Fig. 1 is a result of packaging using the Face-Up FOWLP method.

[0129] When packaging is performed using the Face-Up FOWLP method, a molding layer (110a) (see FIG. 4c) is formed on top of the molding tape using, for example, an epoxy mold compound (EMC) as a sealing material, and the surface is flattened after curing. Subsequently, the upper surface of the cured mold can be processed by chemical mechanical polishing (CMP) to expose the conductive vertical via (150) and the upper ends of the plurality of conductive studs (135).

[0130] When a plurality of conductive studs (135) are attached to a plurality of terminal pads (191, 182, 131, 132, 141, 142) as described above, when a process of chemical mechanical polishing (CMP) is performed on the upper surface of the hardened mold, damage to the terminal pads (191, 182, 131, 132, 141, 142) of the CW laser diode (LD) (190), photonic IC (PIC) (130), and electronic IC (EIC) (140) can be prevented.

[0131] Below, an optical system-in-package (O-SIP) having various exemplary structures of a fiber array unit (FAU) (300) is described with reference to FIGS. 3a to 3d.

[0132] FIG. 3a is a plan view showing an integrated laser system (ILS) having a continuous wave laser (CW laser) built into an optical system-in-package (O-SIP) package having a silicon photonics (SiPh) chip, an electronic IC, and a fiber array unit (FAU) built therein according to a first embodiment of the present invention.

[0133] Referring to FIG. 3a, an optical system-in-package (O-SIP) (100) according to a first embodiment of the present invention provides a package in which a silicon photonics (SiPh) (200) chip, an electronic IC (EIC) (140), and a fiber array unit (FAU) (300) are embedded as photonic ICs (PICs) inside a mold body (110), and a continuous wave laser (CW laser) (190) is embedded inside the package.

[0134] A structure in which a CW laser (190) is built into the package, as in the embodiment illustrated in Fig. 3a, is called an integrated laser system (ILS; IntegratedLaser System).

[0135] The fiber array unit (FAU) (300) illustrated in FIG. 3a has an optical fiber insertion hole (302) partially formed from the rear end of the body (310) into which an optical fiber (350) is inserted, and a waveguide (335) formed at the front end of the optical fiber insertion hole (302) to be aligned with the output waveguide (240) of the silicon photonics (SiPh) (200) chip along its optical axis.

[0136] The optical signal path composed of the optical fiber insertion hole (302) and the waveguide (335) is formed corresponding to the number of optical fibers (350) coupled to the fiber array unit (FAU) (300).

[0137] In this case, when the packaging process according to the FOWLP (Fan Out Wafer Level Package) method is performed on the fiber array unit (FAU) (300) illustrated in FIG. 3a, as illustrated in FIG. 4a, active alignment is performed with an optical fiber (350) inserted into the output waveguide (240) of the silicon photonics (SiPh) (200) chip and the optical fiber insertion hole (302) of the fiber array unit (FAU) (300).

[0138] After that, the silicon photonics (SiPh) (200) chip and the fiber array unit (FAU) (300) are fixed using an adhesive so as to maintain an optical axis alignment between the output waveguide (240) of the silicon photonics (SiPh) (200) chip and the waveguide (335) of the fiber array unit (FAU) (300).

[0139] When the FOWLP process is performed in a state where the silicon photonics (SiPh) (200) chip and the fiber array unit (FAU) (300) are integrated in this way, the optical axis alignment between the output waveguide (240) of the silicon photonics (SiPh) (200) chip and the waveguide (335) of the fiber array unit (FAU) (300) is not misaligned.

[0140] FIG. 3b is a plan view showing an external laser system (ELS) in which a continuous wave laser (CW laser) is detachably coupled to the outside of an optical system-in-package (O-SIP) having a silicon photonics (SiPh) chip, an electronic IC, and a fiber array unit (FAU) built in according to a second embodiment of the present invention.

[0141] Referring to FIG. 3b, an optical system-in-package (O-SIP) (100) according to a second embodiment of the present invention is the same as the first embodiment illustrated in FIG. 3a in that a silicon photonics (SiPh) (200) chip, an electronic IC (140), and a first fiber array unit (FAU) (300) are built inside a mold body (110) of the optical system-in-package (O-SIP), and is different in that a continuous wave laser (CW laser) (190) is detachably coupled to the outside of the package.

[0142] To this end, the optical system-in-package (O-SIP) (100) according to the second embodiment of the present invention has a second fiber array unit (FAU) (300a) built into the mold body (110) so that optical coupling is achieved on the input side of silicon photonics (SiPh) (200).

[0143] The second fiber array unit (FAU) (300a) has an optical signal path formed inside the body, similar to the first fiber array unit (FAU) (300), which is composed of a plurality of optical fiber insertion holes (302) and a waveguide (335).

[0144] An optical system-in-package (O-SIP) (100) according to a second embodiment of the present invention provides an external laser system (ELS; ExternalLaser System) that includes a CW laser (Continuous Wave Laser) (190) outside a mold body (110) by including the second fiber array unit (FAU) (300a).

[0145] In this case, the CW laser (Continuous Wave Laser) (190) uses a structure in which an optical fiber (351) is coupled to the tip through an optical fiber holder (190a), so that the optical fiber (351) provided at the tip can be detachably coupled to the optical fiber insertion hole (302).

[0146] FIG. 3c is a plan view showing an optical system-in-package (O-SIP) having a fiber array unit (FAU) having a through hole formed inside the body for coupling optical fibers according to a first embodiment of the present invention.

[0147] Referring to FIG. 3c, an optical system-in-package (O-SIP) (100) according to a first embodiment of the present invention provides a package in which a silicon photonics (SiPh) (200) chip, an electronic IC (EIC) (140), and a fiber array unit (FAU) (300) are embedded as photonic ICs (PICs) inside a mold body (110) as in the embodiment illustrated in FIG. 3a, and a continuous wave laser (CW laser) (190) is embedded inside the package.

[0148] The difference between the embodiment illustrated in FIG. 3c and the embodiment illustrated in FIG. 3a lies in the structure of the fiber array unit (FAU) (300).

[0149] The fiber array unit (FAU) (300) illustrated in FIG. 3c has a through-type optical fiber insertion hole (304) formed inside the body (310) into which an optical fiber (350) is coupled, and the optical fiber (350) is inserted to the end of the optical fiber insertion hole (304).

[0150] In this case, when the optical fiber (350) is inserted to the end of the optical fiber insertion hole (304), the core (350a) of the optical fiber (350) can be optically aligned with the output waveguide (240) of the silicon photonics (SiPh) (200) chip.

[0151] FIG. 3d is a plan view showing an optical system-in-package (O-SIP) having a fiber array unit (FAU) having a waveguide and a fiber core of silicon photonics (SiPh) and a waveguide for optical alignment within a body according to a first embodiment of the present invention.

[0152] Referring to FIG. 3d, an optical system-in-package (O-SIP) (100) according to a first embodiment of the present invention provides a package in which a silicon photonics (SiPh) (200) chip, an electronic IC (EIC) (140), and a fiber array unit (FAU) (300) are embedded as photonic ICs (PICs) inside a mold body (110) in the same manner as the embodiment illustrated in FIG. 3a, and a continuous wave laser (CW laser) (190) is embedded inside the package.

[0153] The difference between the embodiment illustrated in FIG. 3d and the embodiment illustrated in FIG. 3a lies in the structure of the fiber array unit (FAU) (300).

[0154] The fiber array unit (FAU) (300) illustrated in FIG. 3d has a plurality of waveguides (335) formed inside the body (310) that can automatically be optically aligned with the output waveguide (240) of the silicon photonics (SiPh) (200) chip.

[0155] FIGS. 4A to 4D are process diagrams showing a manufacturing method for manufacturing an optical system-in-package (O-SIP) according to a first embodiment of the present invention at a wafer level using a semiconductor package method according to the FOWLP (Fan Out Wafer Level Package) method.

[0156] Referring to FIGS. 4a to 4d, a manufacturing method for manufacturing an optical system-in-package (O-SIP) according to a first embodiment of the present invention at a wafer level using a semiconductor package method according to the FOWLP method is described.

[0157] Referring to FIG. 4a, in the present invention, first, a plurality of output waveguides (240) of silicon photonics (SiPh) (200) and a plurality of waveguides (335) of a fiber array unit (FAU) (300) are actively aligned so that the optical axis is aligned, and then the silicon photonics (SiPh) (200) chip and the fiber array unit (FAU) (300) are fixed using an adhesive so that the optical axis alignment is maintained.

[0158] In this case, the silicon photonics (SiPh) (200) chip has a plurality of output waveguides (240) on the output side, as shown in FIG. 4b, and additionally has first and second output waveguides (240a, 240b) having a loopback structure on both sides of the plurality of output waveguides (240).

[0159] The above silicon photonics (SiPh) (200) chip has a plurality of output waveguides (240), and among the plurality of output waveguides (240), laser light is input from an external laser system (ELS; ExternalLaser System) into the first and second output waveguides (240a, 240b), and the remaining output waveguides (240) can be used for the purpose of emitting an optical signal from the silicon photonics (SiPh) (200) chip.

[0160] At this time, the input waveguides 2 and 8 into which the laser light is input and the output waveguides 1 and 9 (335) form an optical loopback waveguide between the output waveguide (240) through which the optical signal is emitted from the silicon photonics (SiPh) (200) chip.

[0161] Therefore, the optical loopback waveguide can be used for monitoring out purposes that can be utilized for optical alignment.

[0162] For active alignment of the plurality of output waveguides (240) of the silicon photonics (SiPh) (200) and the plurality of waveguides (335) of the fiber array unit (FAU) (300), an optical fiber (350) is inserted in advance into the optical fiber insertion hole (302) of the fiber array unit (FAU) (300) for optical axis alignment.

[0163] When light is input through, for example, the 2nd and 8th waveguides of the fiber array unit (FAU) (300), the first and second output waveguides (240a, 240b) having the loopback structure of the silicon photonics (SiPh) (200) chip, the light output to the 1st and 9th waveguides (335) of the fiber array unit (FAU) (300) by the first and second output waveguides (240a, 240b) having the loopback structure of the silicon photonics (SiPh) (200) chip can be monitored, thereby aligning the optical axes between the plurality of output waveguides (240) of the silicon photonics (SiPh) (200) and the plurality of waveguides (335) of the 3rd to 7th waveguides of the fiber array unit (FAU) (300).

[0164] After optical axis alignment is achieved between the above silicon photonics (SiPh) (200) chip and the fiber array unit (FAU) (300), they are integrated with each other using an adhesive, and the optical fiber (350) previously inserted into the optical fiber insertion hole (302) of the fiber array unit (FAU) (300) is separated.

[0165] Next, a protective wall (340) is attached to the rear end of the fiber array unit (FAU) (300) to prevent the integrated silicon photonics (SiPh) (200) chip and the optical fiber insertion hole (302) of the fiber array unit (FAU) (300) from being blocked.

[0166] The above protective wall (340) is intended to prevent the optical fiber insertion hole (302) from being blocked during the subsequent epoxy mold compound (EMC) molding process.

[0167] Afterwards, a plurality of conductive studs (135) are attached to a plurality of terminal pads (191, 182, 131, 132, 141, 142) of a photonic IC (PIC) (130) and an electronic IC (EIC) (140) to which a conductive vertical via (150) structure, a CW laser diode (LD) (190), and a fiber array unit (FAU) (300) are attached.

[0168] In addition, first and second heat sinks (170, 171) made of, for example, a Cu pad or a heat dissipating material are attached to the lower surfaces of the photonic IC (PIC) (130) and the electronic IC (EIC) (140).

[0169] Next, as shown in FIG. 4c, a photonic IC (PIC) (130) and an electronic IC (EIC) (140) to which a conductive vertical via (150) structure with a conductive stud (135) attached, a CW laser diode (LD) (190), a fiber array unit (FAU) (300) attached are attached to an adhesive layer (or release tape) of a molding tape at a preset position using a flip chip process, and then packaging is performed using a face-up FOWLP method.

[0170] According to the Face-Up FOWLP method, a molding layer (110a) is formed on the upper part of the molding tape using, for example, an epoxy mold compound (EMC) as a sealing material, and the surface is flattened after curing. Next, the upper surface of the cured mold is processed by chemical mechanical polishing (CMP) to expose the conductive vertical via (150) and the upper ends of the plurality of conductive studs (135).

[0171] Next, the first to third rewiring layers (120-122) are formed on the upper and lower portions of the flattened mold body (110), respectively.

[0172] In the present invention, when a plurality of optical system-in-package (O-SIP) (100) are manufactured at the wafer level, after dicing and separating the die chip from the wafer, the rear end of the diced optical system-in-package (O-SIP) (100), that is, the optical fiber insertion hole (302) of the fiber array unit (FAU) (300) is cut along the cutting line (304) so ​​that the optical fiber insertion hole (302) is exposed, and then polished to expose the optical fiber coupling hole (302), thereby obtaining the optical system-in-package (O-SIP) (100) according to the first embodiment of the present invention as shown in FIG. 4d.

[0173] FIG. 4f and FIG. 4g are cross-sectional views showing an optical module in which an optical system-in-package (O-SIP) according to a first embodiment of the present invention is mounted on a main PCB, and a cross-sectional view showing an optical module in which a ferrule fiber array (FA) is coupled to a fiber array unit (FAU).

[0174] Referring to FIG. 4f, an optical module (500) according to the first embodiment of the present invention can be obtained by mounting the optical system-in-package (O-SIP) (100) obtained in FIG. 4d on a main PCB (400).

[0175] In addition, as illustrated in FIG. 4g, a user can use an optical fiber (350) connected to an optical connector (360) at the rear end of an optical system-in-package (O-SIP) (100) mounted on the main PCB (400) by inserting it into an optical fiber insertion hole (302) of the fiber array unit (FAU) (300). The optical connector (360) can use an LC receptacle or an MT connector.

[0176] In this case, an optical module (500) is completed in which transmission is performed with high efficiency even when an optical fiber (350) is coupled to the optical fiber coupling hole (302) through passive alignment.

[0177] Typically, the outer diameter of a single-mode (SM) optical fiber is 125 μm, and the core diameter of the optical fiber is 10 μm, but the cross-sectional area of ​​the waveguide used to emit the output optical signal from a silicon photonics (SiPh) chip to the outside is 6.7 × 6.7 μm in width × height, and the core of the waveguide is set to 105 × 6.7 nm.

[0178] As a result, the cores of multiple waveguides that emit multiple optical signals of multiple wavelengths generated from a silicon photonics (SiPh) chip have a significantly large difference in diameter from the cores of the optical fiber, making optical alignment difficult.

[0179] In addition, the output waveguide (240) of the silicon photonics (SiPh) (200) chip is disposed on the upper side of the optical system-in-package (O-SIP). Therefore, in order for the output waveguide (240) of the silicon photonics (SiPh) (200) chip and the core (350a) of the optical fiber (350) provided in the fiber array unit (FAU) (300) to be optically aligned, the optical fiber (350) must be disposed on the upper side of the fiber array unit (FAU) (300).

[0180] However, when the diameter of the optical fiber (350) provided in the fiber array unit (FAU) (300) is large and the height from the core of the fiber array unit (FAU) to the surface of the fiber array unit (FAU) is insufficient, there are cases where an optical fiber insertion hole cannot be formed.

[0181] Referring to FIGS. 5a to 7b below, a solution is proposed for a case where an optical fiber insertion hole cannot be formed in a fiber array unit (FAU) (300) provided in an optical system-in-package (O-SIP) (100).

[0182] FIG. 5a and FIG. 5b are side and cross-sectional views, respectively, of an optical system-in-package (O-SIP) for resolving a problem in which the height from the fiber array unit (FAU) core to the FAU surface is insufficient due to a large diameter of the optical fiber.

[0183] Referring to FIGS. 5a and 5b, instead of an optical fiber insertion hole, a plurality of optical fiber receiving grooves (302a) capable of receiving a portion of an optical fiber (350) are formed on the upper portion of the fiber array unit (FAU).

[0184] FIG. 6a and FIG. 6b show that an optical fiber (350) is installed in a plurality of optical fiber receiving grooves (302a) and an optical fiber protection cover (320) for preventing the optical fiber (350) from coming off is coupled to the upper portion of the fiber array unit (FAU).

[0185] Figures 7a and 7b show that a plurality of optical fibers (350) are inserted and installed in a plurality of receiving grooves (302a) while an optical fiber protection cover (320) is coupled to the upper portion of the fiber array unit (FAU).

[0186] As described above, the optical system-in-package (O-SIP) according to the present invention can package a fiber array unit (FAU) together with a continuous wave laser (CW laser), a silicon photonics (SiPh) chip acting as a photonic IC, and an electronic IC inside the package body in the FOWLP manner.

[0187] As a result, in the present invention, a silicon photonics (SiPh) chip as a photonic IC is provided inside the package, and when lateral optical coupling is performed in the horizontal direction with the package body, a semiconductor package method according to the FOWLP method is used to integrate a fiber array unit (FAU) inside the package at the wafer level, thereby easily achieving precise alignment between the optical fiber and the waveguide of the silicon photonics (SiPh) chip.

[0188] Although the present invention has been described and illustrated with specific preferred embodiments as examples, the present invention is not limited to the above embodiments, and various changes and modifications may be made by a person having ordinary skill in the art to which the invention pertains within a scope that does not depart from the spirit of the present invention.

[0189] The optical system-in-package (O-SIP) of the present invention integrates a photonic IC, an electronic IC, and a fiber array unit (FAU) in which lateral optical coupling is performed with the photonic IC using optical FOWLP, and can be applied to an optical module and an optical transceiver.

[0190] The present invention relates to a method for implementing an optical system-in-package (O-SIP), which integrates a system using optical elements into a single package. This can be widely used in the optical communications and optical sensor industries. For optical communications, it can be used for communication between servers within data centers and as an optical transceiver for 5G and 6G communication networks.

[0191] Moreover, since miniaturization and integration are achieved within the package, it can be used for on-board optical communication and chip-to-chip optical communication. Furthermore, it can be used to transmit high-capacity audio and video data between TVs or digital signage and set-top boxes.

Claims

1. A mold body having a first surface and a second surface that are flat on the upper and lower portions; A laser diode positioned inside or outside the mold body to output an optical signal; A photonic IC having a conductive stud connected to a terminal pad on the first surface and molded inside the mold body so that the conductive stud connected to the terminal pad is exposed, and receives an optical signal input from the laser diode through an input waveguide connected to the input side and has a plurality of output waveguides connected to the output side: An electronic IC that is molded inside the mold body so that a conductive stud connected to a terminal pad on the first surface is exposed and drives or interfaces the laser diode and the photonic IC: A fiber array unit (FAU) molded inside the mold body and outputting a plurality of optical signals output through a plurality of output waveguides of the photonic IC to a plurality of optical fibers; and An optical system-in-package (O-SIP) including a redistribution layer formed on the first surface of the mold body and having a plurality of external connection terminals arranged to electrically connect the laser diode, photonic IC, and electronic IC to each other and to the outside.

2. In paragraph 1, The photonic IC is an optical system-in-package (O-SIP) silicon photonics (SiPh) chip that guides the optical signal output from the laser diode to an input waveguide, modulates and separates the optical signal into each wavelength, and outputs the optical signal of each obtained wavelength band through a plurality of output waveguides.

3. In paragraph 1, The above fiber array unit (FAU) has a plurality of waveguides optically aligned with a plurality of output waveguides of the photonic IC at the front of the body and a plurality of optical fiber insertion holes connected to the plurality of waveguides. An optical system-in-package (O-SIP) in which the core of the optical fiber is optically aligned with multiple output waveguides of the photonic IC when the optical fiber is inserted into the optical fiber insertion hole.

4. In paragraph 1, The above fiber array unit (FAU) has a plurality of optical fiber insertion holes penetrating the body, An optical system-in-package (O-SIP) in which the core of the optical fiber is optically aligned with multiple output waveguides of the photonic IC when the optical fiber is inserted into the optical fiber insertion hole.

5. In paragraph 1, The above fiber array unit (FAU) has a plurality of waveguides formed by penetrating the body, An optical system-in-package (O-SIP) in which the plurality of waveguides are optically aligned with the plurality of output waveguides of the photonic IC.

6. In paragraph 1, An optical system-in-package (O-SIP) further comprising an output waveguide having a loopback structure for returning laser light input from the fiber array unit (FAU) to the fiber array unit (FAU) on the outside of a plurality of output waveguides provided in the photonic IC.

7. In paragraph 1, The above fiber array unit (FAU) A plurality of optical fiber receiving grooves each capable of receiving a portion of the plurality of optical fibers on the upper portion of the fiber array unit (FAU); and An optical system-in-package (O-SIP) further comprising an optical fiber protection cover installed on the upper portion of the fiber array unit (FAU) to prevent the plurality of optical fibers installed in the plurality of optical fiber receiving grooves from being detached.

8. A mold body having flat first and second surfaces on the upper and lower portions; A photonic IC having an input waveguide connected to the input side and a plurality of output waveguides connected to the output side, molded inside the mold body on the first surface: and An optical system-in-package (O-SIP) including a fiber array unit (FAU) molded inside the mold body and outputting a plurality of optical signals output through a plurality of output waveguides of the photonic IC to a plurality of optical fibers.

9. In paragraph 8, A laser diode arranged inside or outside the mold body to output an optical signal to the input waveguide of the photonic IC; and It further includes a rewiring layer formed on the first surface of the mold body and having a plurality of external connection terminals arranged to electrically connect the laser diode, photonic IC and electronic IC to each other and to the outside; The photonic IC is an optical system-in-package (O-SIP) that is a silicon photonics (SiPh) chip that guides an optical signal output from the laser diode to the input waveguide, modulates and separates the optical signals into each wavelength, and outputs the optical signals of each wavelength band obtained to the fiber array unit (FAU) through the plurality of output waveguides.

10. In paragraph 9, In the case where the laser diode is placed outside the mold body, the device further includes an input side fiber array unit (FAU) having an optical fiber insertion hole into which an optical fiber connected to the laser diode can be detachably coupled. The above input side fiber array unit (FAU) is an optical system-in-package (O-SIP) formed by connecting an input waveguide of the silicon photonics (SiPh) chip and an optically aligned waveguide through the optical fiber insertion hole.

11. An optical system-in-package (O-SIP) in which a laser diode, a silicon photonics (SiPh) chip, an electronic IC, and a fiber array unit (FAU) are molded inside a mold body having flat first and second surfaces on the upper and lower sides, wherein the silicon photonics (SiPh) chip processes an optical signal generated from the CW laser diode and transmits the optical signal of each wavelength band to a plurality of optical fibers coupled to the fiber array unit (FAU); and A main printed circuit board (PCB) having the optical system-in-package (O-SIP) mounted on the upper surface and a plurality of electronic components that perform transmission and reception control for the optical system-in-package (O-SIP) mounted on the lower surface; The above silicon photonics (SiPh) chip is an optical module that guides optical signals of all wavelengths output from the laser diode to an input waveguide, modulates and separates them into each wavelength, and outputs the optical signals of each obtained wavelength band to the fiber array unit (FAU) through a plurality of output waveguides.

12. In paragraph 11, The above optical system-in-package (O-SIP) has a fiber array unit (FAU) having a plurality of waveguides optically aligned with a plurality of output waveguides of the silicon photonics (SiPh) chip at the front of the body and a plurality of optical fiber insertion holes connected to the plurality of waveguides. An optical module in which the core of the optical fiber is optically aligned with a plurality of output waveguides of the silicon photonics (SiPh) chip when the optical fiber is inserted into the optical fiber insertion hole.

13. A step of performing optical alignment with the output waveguide of the photonic IC while inserting an optical fiber into the optical fiber insertion hole of the fiber array unit (FAU), and when optical alignment is achieved, fixing the photonic IC and the fiber array unit (FAU) using an adhesive; A step of separating the optical fiber inserted into the optical fiber insertion hole of the fiber array unit (FAU) and attaching a protective wall to the rear end of the fiber array unit (FAU) to prevent the optical fiber insertion hole from being blocked; A step of attaching a plurality of conductive studs to a plurality of terminal pads of each of a laser diode, a photonic IC, and an electronic IC, and attaching first and second heat sinks to the lower surfaces of the photonic IC and the electronic IC; A step of attaching the photonic IC and electronic IC to which the laser diode, the fiber array unit, and the like to the adhesive layer of the molding tape at preset positions using a flip chip process, and then forming a molding layer on the upper part of the molding tape using an epoxy mold compound (EMC), and flattening the surface after curing to expose the upper ends of the plurality of conductive studs; A step of forming a rewiring layer on the upper part of the flattened mold body; and A method for manufacturing an optical system-in-package (O-SIP), comprising: a step of dicing and separating a die chip from a wafer, cutting the diced optical system-in-package (O-SIP) along a cutting line so that an optical fiber insertion hole of the fiber array unit is exposed, and polishing the diced optical system-in-package (O-SIP) to expose the optical fiber coupling hole.

14. In paragraph 13, The above optical system-in-package (O-SIP) is manufactured using a face-up FOWLP method.

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