Package and method of forming the same

Abstract

A method of forming a package includes forming a photonic engine. The forming of the photonic engine includes receiving a photonic die including a plurality of grating couplers and a plurality of microlenses attached to the photonic die. The plurality of grating couplers and the plurality of microlenses are configured to optically intercouple in a one-to-one correspondence. A fiber assembly unit is attached to the photonic engine. The fiber assembly unit includes an optical fiber and a laser combining unit configured to optically intercouple the plurality of microlenses and the optical fiber. Embodiments of the present disclosure also provide a package.

Description

Technical Field

[0001] Embodiments of this disclosure relate to packages and methods of forming the same. Background Technology

[0002] Electrical signal transmission and processing is a technology used for signal transmission and processing. In recent years, optical signal transmission and processing has been used in an increasing number of applications, especially due to the use of optical fibers for signal transmission.

[0003] Optical signal transmission and processing are often combined with electrical signal transmission and processing to provide robust applications. For example, optical fibers can be used for long-range signal transmission, while electrical signals can be used for short-range signal transmission, processing, and control. Accordingly, devices integrating optical and electrical components are formed for the conversion between optical and electrical signals, as well as the processing of optical and electrical signals. Therefore, packages can include optical (photonic) dies comprising optical devices and electronic dies comprising electronic devices. Summary of the Invention

[0004] Some embodiments of this disclosure provide a method for forming a package, the method comprising: receiving a photonic engine, the photonic engine including: a photonic die including a plurality of grating couplers; and a plurality of microlenses attached to the photonic die, wherein the plurality of grating couplers and the plurality of microlenses are configured to optically couple to each other in a one-to-one correspondence; and attaching an optical fiber assembly unit to the photonic engine, wherein the optical fiber assembly unit includes: an optical fiber; and a laser combining unit configured to optically couple the plurality of microlenses and the optical fiber to each other.

[0005] Other embodiments of this disclosure provide a method of forming a package, the method comprising: forming a photonic die including a plurality of grating couplers, wherein the characteristic wavelengths of the plurality of grating couplers are different from each other, and the plurality of grating couplers have a first spacing; bonding an electron die to the photonic die; forming a gap-filling region next to and above the electron die; and attaching a support substrate to the gap-filling region, wherein the support substrate includes a plurality of microlenses, and wherein the plurality of microlenses have a second spacing the same as the first spacing.

[0006] Further embodiments of this disclosure provide a package comprising: a photonic die including a plurality of grating couplers having a first spacing and having different structures from each other; an electron die to which a signal is coupled; a dielectric region surrounding the electron die and located above the photonic die; a support substrate located above the dielectric region, wherein the support substrate includes a plurality of microlenses having a second spacing the same as the first spacing; and an optical fiber assembly unit including an optical fiber configured to receive a laser beam propagating from the plurality of microlenses. Attached Figure Description

[0007] The aspects of this disclosure are best understood from the following detailed description when read in conjunction with the accompanying drawings. It should be noted that, in accordance with standard industry practice, the various components are not drawn to scale. In fact, the dimensions of the various components may be arbitrarily increased or decreased for clarity of discussion.

[0008] Figures 1 to 7 A view showing an intermediate stage in the formation of a package including a photonic die, according to some embodiments, is shown.

[0009] Figure 8 A package is shown in which a laser beam propagates through multiple microlenses and multiple grating couplers according to some embodiments.

[0010] Figure 9 The optical coupling of a grating coupler array, a microlens array, and a row of optical fibers according to some embodiments is shown.

[0011] Figure 10 The illustration shows the combination of multiple laser beams with different wavelengths into an optical fiber (or the splitting of a laser beam into multiple laser beams with different wavelengths) according to some embodiments.

[0012] Figure 11A and 11B A pattern of a bandpass filter according to some embodiments is shown.

[0013] Figure 12A and Figure 12B A pattern of a reflector according to some embodiments is shown.

[0014] Figure 13 The illustration shows, according to some embodiments, the merging of multiple laser beams with different wavelengths into two optical fibers (or the splitting of two laser beams into multiple laser beams with different wavelengths).

[0015] Figure 14 A schematic diagram illustrating the function of a package including a photonic die according to some embodiments is shown.

[0016] Figure 15 A process flow for forming a photonic package according to some embodiments is shown. Detailed Implementation

[0017] The following disclosure provides numerous different embodiments or instances of various components for implementing this application. Specific examples of components and arrangements are described below to simplify this disclosure. Of course, these are merely examples and not intended to be limiting. For example, in the following description, forming a first component above or on a second component may include embodiments where the first and second components are in direct contact, and may also include embodiments where an additional component may be formed between the first and second components, thereby allowing the first and second components to not be in direct contact. Additionally, reference numerals and / or characters may be repeated in various instances of this disclosure. This repetition is for clarity and simplicity and does not, in itself, indicate a relationship between the individual embodiments and / or configurations discussed.

[0018] Furthermore, for ease of description, spatial relative terms such as “below,” “under,” “lower,” “above,” and “upper” may be used herein to describe the relationship between one element or component and another, as shown in the figures. In addition to the orientations shown in the figures, spatial relative terms are intended to encompass different orientations of the device during use or operation. The device may be positioned in other ways (rotated 90 degrees or in other orientations), and the spatial relative descriptors used herein can be interpreted accordingly.

[0019] A package including a photonic engine configured for wavelength division multiplexing (WDM) and a method of forming the same are provided. According to some embodiments of this disclosure, the photonic engine includes a plurality of grating couplers forming an array of grating couplers and a plurality of microlenses forming an array of microlenses. Multiple laser beams of different wavelengths can be projected through rows of grating couplers and onto corresponding rows of microlenses. The multiple laser beams are then combined into the same optical fiber. Similarly, lasers emitted in an optical fiber can be multiplexed into multiple laser beams of different wavelengths. The multiple laser beams can be projected onto corresponding rows of microlenses and further onto corresponding rows of grating couplers.

[0020] Multiple grating couplers in the same column have different structures suitable for the wavelengths of the corresponding laser beams. Accordingly, the combined bandwidth of multiple wavelengths is increased by using multiple grating couplers.

[0021] The embodiments discussed herein provide examples of how the subject matter of this disclosure can be made or used, and those skilled in the art will readily understand that modifications can be made while remaining within the intended scope of the different embodiments. Similar reference numerals are used to denote similar elements throughout the various views and illustrative embodiments. While method embodiments may be discussed as being performed in a particular order, other method embodiments may be performed in any logical order.

[0022] Figures 1 to 7A cross-sectional view is shown of an intermediate stage in the formation of a photonic package according to some embodiments of the present disclosure. Also... Figure 15 The process flow shown schematically illustrates the corresponding process.

[0023] refer to Figure 1 This formed the photonic chip 20'. Figure 15 In the process flow 200 shown, the corresponding process is illustrated as process 202. According to some embodiments, a photonic die 20' is part of an uncut photonic wafer 20 that includes a plurality of identical photonic dies 20'. The photonic die 20' may optionally be referred to as a photonic integrated circuit (PIC) die 20'.

[0024] According to some embodiments, the photonic die 20' may include a semiconductor substrate 22, which may be a silicon substrate. A dielectric layer 26 is formed over the semiconductor substrate 22. According to some embodiments, the dielectric layer 26 is an etch stop layer used in subsequent formation of conductive components. The material of the dielectric layer 26 may include silicon nitride, silicon oxynitride, silicon carbide, silicon oxycarbide, silicon oxide, etc.

[0025] According to some embodiments, the photonic die 20' may include an integrated circuit device (not shown) formed on the surface of the semiconductor substrate 22. According to some embodiments, the integrated circuit device (if formed) is used to support the functionality of the photonic die. The integrated circuit device may include active devices, such as transistors and / or diodes. The integrated circuit device may also include passive devices, such as capacitors, resistors, etc. According to an alternative embodiment, no integrated circuit device is formed in the photonic die 20'.

[0026] The photonic die 20' may include photonic devices such as waveguides, grating couplers, modulators, etc. The waveguide may include silicon waveguides and / or silicon nitride waveguides. According to some embodiments, a dielectric layer 28 is formed, and the dielectric layer 28 may include silicon oxide, silicon oxynitride, aluminum oxide, aluminum nitride, etc.

[0027] According to some embodiments, a dielectric layer 28 is formed above the grating coupler 48. The dielectric layer 28 may comprise a transparent and low-loss dielectric material, such as silicon oxide. Multiple dielectric layers 28 may comprise an intermetallic dielectric (IMD), which may comprise a low-k dielectric material, such as porous silicon oxynitride. An etch stop layer may also be formed between the low-k dielectric materials. The etch stop layer may comprise AlN, AlO, SiON, or multiple layers thereof.

[0028] An interconnect structure 32 is formed, which may include metal vias and metal lines, as well as corresponding portions of the dielectric layer 28. The metal vias and metal lines can be formed using a single damascene process and / or a dual damascene process. The interconnect structure 32 may further include aluminum pads (including aluminum-copper), a dielectric passivation layer, etc. The dielectric layer 28 may also include an organic dielectric layer containing an organic dielectric material, which may be a polymer, such as polyimide, polybenzoxazole (PBO), benzocyclobutene (BCB), etc.

[0029] According to some embodiments, wafer 20 (and photonic die 20' therein) includes a device region and an annular region surrounding the device region. Interconnect structure 32 is disposed above the device region. Sealing ring structure 40 is formed in the peripheral region of photonic die 20' and surrounds the interconnect structure. The device region may contain a plurality of transistors (not shown) located on the surface of substrate 22 and extending into substrate 22. The plurality of transistors are functionally interconnected via metal components in the interconnect structure.

[0030] The sealing ring structure 40 includes a continuous metal component extending around the interconnecting structure, interconnecting the metal component to form a solid wall therein without openings. The sealing ring structure 40 includes a plurality of wires and conductive vias (not shown separately). The wires and conductive vias are formed of a material comprising a copper atomic percentage greater than 80% (in some embodiments, greater than about 90% or greater than about 95%).

[0031] The conductive via 42 is formed as part of the interconnect structure 32. The conductive via 42 may contain a conductive material such as copper or tungsten, and may or may not include a diffusion barrier formed by Ti, TiN, Ta, TaN, or multiple layers. According to some embodiments, the conductive via 42 may be positioned on a metal pad.

[0032] A bonding layer 44 is formed over the conductive via 42. According to some embodiments, the bonding layer 44 may have a multilayer or single-layer structure. The material of the bonding layer 44 may comprise a silicon-containing dielectric material, such as silicon oxide, silicon nitride, silicon oxynitride, silicon carbide, silicon oxycarbide, or combinations thereof.

[0033] Bond pads 46 are formed in dielectric layer 44. According to some embodiments, bond pads 46 may contain copper and may contain diffusion barriers such as Ti, TiN, Ta, TaN, etc. The formation process may include etching bond layer 44 to form an opening, depositing conductive material to fill the opening, and performing a planarization process to remove portions of the conductive material above bond layer 44.

[0034] According to some embodiments, the photonic devices in the photonic die 20' may include a plurality of grating couplers 48, which, according to some embodiments, may be formed of silicon. For example, a silicon layer may be formed on a dielectric layer 26, for example, by bonding the silicon layer to the dielectric layer 26 and then patterning the silicon layer by etching, thereby forming waveguides, grating couplers, etc.

[0035] Multiple grating couplers 48 may include at least one column of grating couplers 48 (e.g. Figure 9 (as shown), and may include multiple rows of grating couplers 48, which will be formed as an array. Figure 1 Exemplary columns of grating couplers 48 are shown, labeled grating couplers 48-1-1, 48-2-1, 48-3-1, and 48-4-1. According to some embodiments, grating couplers 48-1-1, 48-2-1, 48-3-1, and 48-4-1 are adapted to receive or project laser beams of different wavelengths, and the corresponding wavelengths are referred to as the characteristic wavelengths of the corresponding grating coupler 48. The grating coupler exhibits the lowest loss when operating with a laser beam having the same wavelength as the characteristic wavelength. The grating coupler exhibits higher loss when operating with a laser beam having a wavelength greater than or less than the characteristic wavelength. Accordingly, the structures of grating couplers 48-1-1, 48-2-1, 48-3-1, and 48-4-1 are different from each other.

[0036] According to some embodiments, a transparent dielectric region 50 is formed over the grating coupler 48. The formation process may include etching the dielectric layer 28 to form an opening overlapping the grating coupler 48; filling the opening with a dielectric material having good transparency; and performing a planarization process, such as a chemical mechanical polishing (CMP) process or a mechanical polishing process. An exemplary material for the transparent dielectric region 50 may include silicon oxide.

[0037] refer to Figure 2 The device die 52 (which may be an electronic integrated circuit (EIC) die 52) is bonded to the photonic die 20'. Figure 15 In the process flow 200 shown, the corresponding process is shown as process 204. According to some embodiments, the EIC die 52 includes a semiconductor substrate 56 (which may be a silicon substrate) and an integrated circuit 54 formed on the surface of the semiconductor substrate 56.

[0038] Integrated circuit 54 may include active devices such as transistors and diodes, and may or may not include passive devices such as capacitors, inductors, and resistors. For example, according to some embodiments, the transistor in active device 54 may include source and drain regions, a gate dielectric, a gate electrode, and a gate spacer.

[0039] The EIC die 52 also includes a dielectric layer 60 as a bonding layer, in which bonding pads 58 are formed. According to some embodiments, the EIC die 52 may include a sealing ring 62 forming a complete ring (when viewed from a bottom view of the EIC die 52) adjacent to the peripheral region of the EIC die 52. The EIC die 52 may include interconnect structures comprising a dielectric layer and metal vias and metal lines located within the dielectric layer. The dielectric layer may include a low-k dielectric layer, which may be formed from a carbon-containing dielectric layer.

[0040] According to some embodiments, the EIC die 52 includes a device region and an annular region surrounding the device region. A sealing ring structure 62 is formed in the peripheral region and surrounds the interconnect structure and the device region.

[0041] The sealing ring structure 62 includes a continuous metal component extending around the interconnecting structure, wherein the metal component is interconnected as a solid wall without openings. The sealing ring structure 62 includes a plurality of wires and conductive vias (not shown separately). The wires and conductive vias are formed of a material comprising a copper atomic percentage greater than 80% (in some embodiments, greater than about 90% or greater than about 95%).

[0042] The bonding between the photonic die 20' and the EIC die 52 can include metal-to-metal direct bonding, solder bonding, or a hybrid bonding including metal-to-metal direct bonding and fusion bonding. For example, bonding layer 60 can be bonded to bonding layer 44 by fusion bonding.

[0043] According to some embodiments, EIC die 52 may include an integrated circuit 54 for communicating with photonic die 20', such as circuitry for controlling the operation of photonic die 20'. For example, integrated circuit 54 may include a controller, driver, amplifier, etc., or combinations thereof. EIC die 52 may also include a CPU. According to some embodiments, EIC die 52 includes circuitry for processing electrical signals received from (or transmitted to) photonic die 20'. EIC die 52 may also control high-frequency signal transmission of photonic die 20' based on electrical signals (digital or analog) received from another device or die. According to some embodiments, EIC die 52 may include circuitry providing serializer / deserializer (SerDes) functionality. In this way, the EIC can serve as part of an I / O interface between optical and electrical signals.

[0044] It should be understood that, Figure 1 and Figure 2 The process shown is a wafer-level process, wherein, according to some embodiments, multiple EIC dies 52 can be bonded to multiple photonic dies 20' of the photonic wafer 20. Figure 3A gap-filling process according to some embodiments is illustrated, wherein the gaps between adjacent EIC dies 52 are filled to form a dielectric region 74 surrounding the EIC die 52. Figure 15 In the process flow 200 shown, the corresponding process is shown as process 206. The dielectric region 74 is also referred to as the gap-filling region 74.

[0045] The gap-filling region 74 may include a dielectric layer and may or may not include a dielectric barrier located beneath the dielectric layer. The formation of the dielectric barrier may include conformal deposition processes such as ALD, CVD, etc. The material of the dielectric barrier is selected to have good adhesion to the EIC die 52. According to some embodiments, the dielectric barrier is formed of silicon nitride, silicon carbonitride, silicon oxynitride, silicon carbide, etc., or the dielectric barrier includes silicon nitride, silicon carbonitride, silicon oxynitride, silicon carbide, etc. The dielectric layer may be transparent and may include silicon oxide, silicon oxynitride, etc.

[0046] Next, refer to Figure 4 A bonding layer 76 is deposited on the gap-filling region 74 and the EIC die 52 using a deposition process. According to some embodiments, the bonding layer 76 is formed of or contains silicon oxide, silicon oxynitride, etc.

[0047] The support substrate 78 (which may be a wafer) is bonded to the bonding layer 76. Figure 15 In the process flow 200 shown, the corresponding process is illustrated as process 208. According to some embodiments, the support substrate 78 includes a bonding layer 80 and a silicon substrate 82 attached to the bonding layer 80. The bonding layer 80 may be formed of or contain a silicon-containing dielectric material, such as silicon oxide, silicon oxynitride, silicon carbonitride, etc. Bonding may include fusion bonding, whereby the bonding layer 80 is bonded to the bonding layer 76.

[0048] According to some embodiments, the support substrate 78 includes microlenses 84, for example, formed as part of the silicon substrate 82 by etching the silicon substrate 82. The support substrate 78 may further include a protective layer (not shown), an anti-reflective coating (ARC), etc., formed on the silicon substrate 82. According to some embodiments, the spacing P1 of the microlenses 84 is the same as the spacing P2 of the grating couplers 48. For example, the spacings P1 and P2 can be in the range of about 100 μm and about 200 μm. According to some embodiments, the microlenses 84 have the same number as the grating couplers 48. The microlenses 84 can be formed as a microlens array having the same number of rows and columns as the grating coupler array 48.

[0049] Next, remove the semiconductor substrate 22 ( Figure 3 ).exist Figure 15In the process flow 200 shown, the corresponding process is illustrated as process 210. Removal processes may include CMP processes, mechanical polishing processes, etc. Accordingly, dielectric layer 26 is exposed. Dielectric layer 26 may be removed or thinned. According to an alternative embodiment where the photonic die 20' includes active devices, semiconductor substrate 22 may remain unremoved.

[0050] In subsequent processes, such as Figure 5 As shown, dielectric layer 86 and metal pads 87 are formed. Next, refer to... Figure 6 This forms a dielectric layer 88 and redistribution lines (RDLs) 90. Figure 15 In the process flow 200 shown, the corresponding process is illustrated as process 212. The dielectric layer 88 may include inorganic dielectric materials (such as silicon oxide, silicon nitride, etc.) and / or organic dielectric materials (such as polymers). Polymers may include polyimide, PBO, BCB, etc.

[0051] refer to Figure 7 This allows for the formation of further conductive components, including the electrical connector 92. According to some embodiments, the electrical connector 92 may include a metal pillar 94 and a solder region 96. Figure 15 In the process flow 200 shown, the corresponding process is shown as process 214. Thus, a reconstructed wafer 102 is formed.

[0052] In subsequent processes, a dicing process (also known as a single-chip dicing process) is performed to dice and reconstruct the wafer 102 and form multiple optical engines 102', which are also referred to as photonic engines or photonic packages. Figure 15 In the process flow 200 shown, the corresponding process is shown as process 216. Multiple optical engines 102' are identical to each other. Each of the multiple optical engines 102' may include a photonic die 20', an EIC die 52, and a block of support substrate 78 cut from a wafer-level support substrate 78.

[0053] Figure 8 The use of a photonic engine 102' according to some embodiments is illustrated. The photonic engine 102' can be coupled to the underlying packaging assembly 110 to form a package 104. Figure 15 In the process flow 200 shown, the corresponding process is illustrated as process 218. The packaging assembly 110 below may include an interposer, a packaging substrate, a printed circuit board, etc. The fiber assembly unit (FAU) 106 ( Figure 8 Not shown in the image, see reference. Figure 10 or Figure 13 ) is attached to photon engine 102'. Fiber optic cable 112 ( Figure 10 or Figure 13 ) Attached to the optical fiber assembly unit 106.

[0054] In the following discussion of exemplary use of the photonic package 104, it is assumed that a laser beam 114 is generated in response to an electrical signal in the EIC die 52. Figure 8 The optical signal is generated as a laser beam 114 (including laser beams 114A, 114B, 114C, and 114D as examples) and projected from the grating coupler 48. The laser beam 114 passes through the microlens 84 and is projected into the optical fiber 112, as shown. Figure 10 or Figure 13 As shown.

[0055] According to an optional embodiment, the laser beam 114 propagates in opposite directions. For example, the laser beam originates from optical fiber 112 ( Figure 10 or Figure 13 The laser beams are projected out and split into multiple laser beams 114 with different wavelengths. The laser beams 114 pass through the microlens 84 and are received by the grating coupler 48, and are further processed by the photonic die 20' and the EIC die 52.

[0056] According to some embodiments, the laser beams 114 (such as laser beams 114A, 114B, 114C, and 114D) have different wavelengths. For example, when using coarse wavelength division multiplexing (CWDM), the wavelength spacing can be 20 nm. The wavelengths of the CWDM can include 1290 nm, 1310 nm, and 1330 nm, which have a wavelength spacing of 20 nm. Therefore, the grating couplers 48-1-1, 48-2-1, and 48-3-1 have structures configured to operate in coordination with the wavelengths of the CWDM (such as 1290 nm, 1310 nm, and 1330 nm), respectively.

[0057] It is worth noting that a single grating coupler 48 may not be able to support the wide bandwidth of WDM, such as CWDM, LWDM (with a wavelength spacing of 4.5 nm), and Dense Wavelength Division Multiplexing (DWDM, with a wavelength spacing of 0.8 nm). However, by having different structures and different characteristic wavelengths, multiple grating couplers 48 can collectively support the wide bandwidth of WDM.

[0058] Figure 9 A schematic diagram illustrating the operation and relationship of a grating coupler 48, a microlens 84, an optical fiber 112, and a laser beam 114 according to some exemplary embodiments is shown. The grating coupler 48 and the microlens 84 are arranged as a grating coupler array (also designated 48) and a microlens array (also designated 84), respectively. In the exemplary embodiments shown, each of the grating coupler array 48 and the microlens array 84 has 4 rows and 20 columns. In other embodiments, the number of rows can be arbitrary, for example, in the range of 2 to 16. The number of columns can be arbitrary, for example, in the range of 1 to 128.

[0059] In the following discussion, three numbers separated by two "-" symbols can be used to indicate specific grating couplers and microlenses. The first number can be 48 or 84, indicating that it is a grating coupler or a microlens. The second number after the first "-" symbol indicates the corresponding row number. The third number after the second "-" symbol indicates the corresponding column number. For example, grating coupler 48-1-1 is located in row 1 and column 1. Grating coupler 48-2-1 is located in row 2 and column 1. Grating coupler 48-1-20 is located in row 1 and column 20.

[0060] A row of optical fibers 112 is shown. A specific optical fiber can be indicated using two numbers separated by a "-" symbol. The first number, 112, indicates that it is an optical fiber, and the second number after the "-" symbol indicates its corresponding column number. According to some embodiments, the grating coupler 48, microlens 84, and optical fiber have the same number of columns, and their columns have a one-to-one correspondence, as will be discussed in detail later.

[0061] According to some embodiments, the grating couplers 48 in the same row have the same structure and the same characteristic wavelength. The structure of the grating couplers 48 in each row differs from the structure of the grating couplers 48 in other rows. The characteristic wavelength of the grating couplers 48 in each row differs from the characteristic wavelength of the grating couplers 48 in other rows.

[0062] For example, grating couplers 48-1-1, 48-1-2, ... through 48-1-20 have the same structure and the same characteristic wavelength (such as 1,290 nm). Grating couplers 48-2-1, 48-2-2, ... through 48-2-20 have the same structure and the same characteristic wavelength (such as 1,310 nm). Grating couplers 48-3-1, 48-3-2, ... through 48-3-20 have the same structure and the same characteristic wavelength (such as 1,330 nm). Accordingly, the grating couplers 48 in each column of grating couplers collectively cover (and may extend beyond when using the fourth row) the bandwidth of the CWDM, which covers 1,290 nm, 1,310 nm, and 1,330 nm.

[0063] Referring to the first column of the grating coupler 48 as an example, four laser beams 114 (including laser beams 114A, 114B, 114C, and 114D) are transmitted through waveguides in the photonic die 20' to grating couplers 48-1-1, 48-2-1, 48-3-1, and 48-4-1, respectively. Laser beams 114A, 114B, 114C, and 114D are physically separated laser beams and are labeled as laser beams 114A / 114B / 114C / 114D, as shown below. Figure 9As shown. The " / " symbol indicates that laser beams 114A, 114B, 114C, and 114D are separate laser beams, as shown. Figure 8 As shown.

[0064] Laser beams 114A, 114B, 114C, and 114D are projected from grating couplers 48-1-1, 48-2-1, 48-3-1, and 48-4-1, respectively, and then projected one-to-one onto microlenses 84-1-1, 84-2-1, 84-3-1, and 84-4-1. Therefore, the laser beams projected onto and from microlenses 84-1-1, 84-2-1, 84-3-1, and 84-4-1 are labeled as laser beams 114A / 114B / 114C / 114D to indicate that these laser beams are still separate laser beams. Figure 8 and Figure 10 As shown.

[0065] The laser beams 114A / 114B / 114C / 114D corresponding to the first row of grating couplers 48 and the first row of microlenses 84 are combined into optical fiber 112-1. Accordingly, the laser beam transmitted through optical fiber 112-1 is labeled (114A+114B+114C+114D), where the "+" sign indicates that these laser beams are combined into a single laser beam. The first row of grating couplers 48, the first row of microlenses 84, and the first optical fiber 112 are referred to as optically coupled.

[0066] like Figure 9 As shown, additional laser beams 114A, 114B, 114C, and 114D are transmitted to the second row of grating couplers 48-1-2, 48-2-2, 48-3-2, and 48-4-2, respectively. The laser beams 114A, 114B, 114C, and 114D transmitted to the second row of grating couplers 48-1-2, 48-2-2, 48-3-2, and 48-4-2 can carry optical signals different from the corresponding laser beams 114A, 114B, 114C, and 114D transmitted through the first row of grating couplers 48-1-1, 48-2-1, 48-3-1, and 48-4-1, respectively. Similarly, additional laser beams 114A, 114B, 114C, and 114D are projected onto the second row of microlenses 84-1-2, 84-2-2, 84-3-2, and 84-4-2, respectively, and are combined into the second optical fiber 112-2. The second row of grating couplers 48, the second row of microlenses 84, and the second optical fiber 112 are referred to as optically coupled.

[0067] The functions of the remaining columns of grating couplers 48, microlenses 84, optical fibers 112, and corresponding laser beams 114 are similar to those discussed above and can be implemented from the aforementioned discussion. Accordingly, in the illustrated example, 4x20 optical signals (which may be different from each other) can be combined into 20 optical fibers 112. By increasing the number of columns and rows, the number of optical signals transmitted simultaneously can be further increased. Since the optical signals transmitted through the optical fibers 112 are processed by different grating couplers configured to handle different wavelengths, by combining the functions of the grating couplers 48 in the same column, the bandwidth of the optical signals can be increased without being limited by the bandwidth of a single grating coupler.

[0068] Figure 10 The attachment of the fiber optic assembly unit (FAU) 106 to the package 104 and the photonic engine 102' is shown. The FAU 106 includes a laser combining unit 107 configured to combine parallel laser beams into a single laser beam. Figure 10 The operation of laser beams 114A, 114B, 114C, and 114D projected from microlenses 84 in the same column (which may be microlenses 84-1-1, 84-2-1, 84-3-1, and 84-4-1 in the first column as examples) is also shown. Laser beams 114A, 114B, 114C, and 114D are parallel to each other and are reflected by reflector 120. The reflected laser beams are projected onto bandpass filters (or bandpass filter portions) 122A, 122B, 122C, and 122D, which are part of bandpass filter 122.

[0069] Bandpass filters 122A, 122B, 122C, and 122D are configured to allow laser beams 114A, 114B, 114C, and 114D to pass through, respectively, and are configured to block the remaining laser beams. For example, bandpass filter 122A allows laser beam 114A to pass through and blocks laser beams 114B, 114C, and 114D. Similarly, bandpass filter 122D allows laser beam 114D to pass through and blocks laser beams 114A, 114B, and 114C.

[0070] After laser beams 114A, 114B, 114C, and 114D pass through bandpass filter 122, they are projected onto reflector 126, which is configured to reflect all laser beams 114, even though their wavelengths are different from each other. The reflected laser beams 114 are then further projected onto other bandpass filters configured to prevent them from passing through, and are reflected again. Reflection can occur back and forth until the laser beams 114 are projected into their respective optical fibers 112.

[0071] For example, laser beam 114A passing through bandpass filter 122A will be reflected sequentially by reflector 126, bandpass filter 122B, reflector 126, bandpass filter 122C, reflector 126, and bandpass filter 122D, and then projected into optical fiber 122. Laser beam 114B passing through bandpass filter 122B will be reflected sequentially by reflector 126, bandpass filter 122C, reflector 126, and bandpass filter 122D, and then projected into optical fiber 122. Laser beam 114C passing through bandpass filter 122C will be reflected sequentially by reflector 126 and bandpass filter 122D, and then projected into optical fiber 122. Laser beam 114D passing through bandpass filter 122D will be directly projected into optical fiber 122.

[0072] pass Figure 10 In the structure described, laser beams 114A, 114B, 114C, and 114D, after passing through a row of grating couplers 48 and a row of microlenses 84, are combined into a single optical fiber 112. Correspondingly, laser beams 114 from multiple rows of grating couplers 48 and multiple rows of microlenses 84 are combined into multiple (one row) optical fibers 112, as shown below. Figure 9 As shown.

[0073] Figure 11A An exemplary bandpass filter 122 according to some embodiments is shown. The bandpass filter 122 includes a plurality of elongated bandpass filters 122A, 122B, 122C, and 122D, each elongated bandpass filter being used to allow a laser beam with one characteristic wavelength to pass through and to block laser beams with other characteristic wavelengths. Laser beams projected from all microlenses 84 in the same row can be projected onto the same bandpass filter 122A, 122B, 122C, or 122D. The lengths of the bandpass filters 122A, 122B, 122C, and 122D are sufficiently large to receive laser beams passing through the entire row of grating couplers 48 and the entire row of microlenses 84.

[0074] Figure 11B An exemplary bandpass filter 122 according to an alternative embodiment is shown. These embodiments are similar to... Figure 11A The difference in the embodiments is that, Figure 11AThe long bandpass filters 122A, 122B, 122C, and 122D are divided into a bandpass filter array (also designated as bandpass filter array 122), which may have the same number of rows and columns as the grating coupler array 48 and the microlens array 84. The bandpass filter array 122 also has a one-to-one correspondence with the grating coupler array 48 and the microlens array 84. Accordingly, a laser beam transmitted to a grating coupler will be projected onto the corresponding microlens 84 and then onto the corresponding bandpass filter 122 in the bandpass filter array 122. For example, a laser beam 114C corresponding to grating coupler 48-3-1 in the third row of the grating coupler array 48 can pass through microlens 84-3-1 in the third row of the microlens array 84 and be projected into optical fiber 122-3. Figure 9 ).

[0075] Figure 12A and Figure 12B A reflector 126 according to some embodiments is shown. Figure 12A In the design, reflector 126 is divided into three elongated strips 126A, 126B, and 126C. Each elongated strip is used to reflect laser beams that have passed through or been reflected by bandpass filters 122A, 122B, and 122C. This allows the laser beam to be reflected from the bandpass filters 122A, 122B, and 122C. Figure 9 This can be seen from [the text]. Figure 12B In the illustrated embodiment, reflector 126 is a sufficiently large monolithic piece such that all laser beams passing through or reflected by bandpass filters 122A, 122B, and 122C will be projected onto and reflected by reflector 126. Reflector 126 may also include a plurality of spaced-apart reflective elements, for example, having 3x20 elements.

[0076] Understandable, Figure 10 The structure shown can be used for laser beams propagating in the opposite direction to those described above. This mechanism is consistent with the reference... Figure 8 The mechanisms discussed are basically the same, the difference being that the propagation direction of the laser beam is opposite.

[0077] For example, an optical fiber 112-1 can be used to transmit a laser beam containing combined laser beams 114A, 114B, 114C, and 114D, and this laser beam containing combined laser beams 114A, 114B, 114C, and 114D can be projected onto a bandpass filter 122D. Laser beam 114D passes through bandpass filter 122D. Laser beams 114A, 114B, and 114C are reflected by bandpass filter 122D and reflector 126, and projected onto bandpass filter 122C.

[0078] Then, laser beam 114C passes through bandpass filter 122C. Laser beams 114A and 114B are reflected by bandpass filter 122C and reflector 126 and projected onto bandpass filter 122B. Laser beam 114B passes through bandpass filter 122B. Laser beam 114A is reflected by bandpass filter 122B and reflector 126 and passes through bandpass filter 122A. Laser beams 114A, 114B, 114C, and 114D are reflected by reflector 120 to reach microlenses 84-1-1, 84-2-1, 84-3-1, and 84-4-1, respectively, and then propagate to grating coupler 48.

[0079] Figure 13 The operation of laser beams 114A, 114B, 114C, and 114D projected from a series of microlenses 84 (hypothetically microlenses 84-1-1, 84-2-1, 84-3-1, and 84-4-1) is illustrated. This embodiment is similar to... Figure 10 The embodiment in the reference differs in that laser beams 114A, 114B, 114C, and 114D are combined into more than one optical fiber 112. For example, laser beams 114A and 114B are combined into optical fiber 112A, and laser beams 114C and 114D are combined into optical fiber 112B. This operation can be seen from the reference... Figure 10 This will be achieved through discussion.

[0080] Figure 14 A schematic diagram of the operation of package 104 according to some embodiments is shown. The diagram shows a row of grating couplers 48, a row of microlenses 84, and an optical fiber 112. Transceivers 130 in the photonic engine and transceivers 132 at the distal end of the optical fiber 112 are used to transmit or receive signals. A one-to-one correspondence between the grating couplers 48 and the microlenses 84 is shown. The merging of laser beams 114A, 114B, 114C, and 114D is shown. Furthermore, the use of bidirectional arrows to indicate laser beams 114A, 114B, 114C, and 114D indicates that the structure is configured to merge laser beams 114 in the photonic engine into the optical fiber, and to transmit laser beams 114 through the optical fiber, or to transmit laser beams 114 in the opposite direction.

[0081] The embodiments of this disclosure have several advantageous features. By using multiple grating couplers with different structures and different characteristic wavelengths, a wide bandwidth can be covered by combining multiple grating couplers. The resulting optical package exhibits reduced loss over a wide bandwidth. The bandwidth can be increased by simply adding more grating couplers.

[0082] According to some embodiments of the present disclosure, a method includes receiving a photonic engine including a photonic die including a plurality of grating couplers; and a plurality of microlenses attached to the photonic die, wherein the plurality of grating couplers and the plurality of microlenses are configured to optically couple to each other in a one-to-one correspondence; and attaching an optical fiber assembly unit to the photonic engine, wherein the optical fiber assembly unit includes an optical fiber; and a laser combining unit configured to optically couple the plurality of microlenses and the optical fiber to each other.

[0083] In one embodiment, multiple grating couplers are aligned in a column, and the multiple grating couplers have different structures. In another embodiment, the multiple grating couplers have the same spacing as the multiple microlenses. In yet another embodiment, the method further includes performing a gap-filling process to form a gap-filling region surrounding the electron die after bonding the electron die to the photonic die.

[0084] In one embodiment, the method further includes: after forming the gap-filling region, forming a plurality of transparent regions within the gap-filling region, and the plurality of transparent regions overlapping with a plurality of grating couplers. In another embodiment, attaching the plurality of microlenses includes attaching a support substrate above the photonic die, wherein the support substrate includes a plurality of microlenses.

[0085] In one embodiment, the fiber optic assembly unit includes multiple bandpass filters configured to filter laser beams with different wavelengths. In another embodiment, the fiber optic assembly unit includes: a first reflector configured to reflect laser beams projected from multiple microlenses, wherein the first reflector reflects the laser beams to the multiple bandpass filters; and a second reflector configured to reflect laser beams that have passed through the multiple bandpass filters.

[0086] According to some embodiments of this disclosure, a method includes: forming a photonic die including a plurality of grating couplers, wherein the characteristic wavelengths of the plurality of grating couplers are different from each other, and the plurality of grating couplers have a first spacing; bonding an electron die to the photonic die; forming a gap-filling region next to and above the electron die; and attaching a support substrate to the gap-filling region, wherein the support substrate includes a plurality of microlenses, and wherein the plurality of microlenses have a second spacing the same as the first spacing.

[0087] In one embodiment, the method further includes attaching an optical fiber assembly unit to a support substrate, wherein the optical fiber assembly unit is configured to combine laser beams propagating from a plurality of grating couplers into an optical fiber within the optical fiber assembly unit. In another embodiment, the optical fiber assembly unit includes an optical fiber; and a laser combining unit configured to couple a plurality of microlenses and fiber optics to each other. In yet another embodiment, the laser combining unit includes a plurality of bandpass filters configured to filter laser beams of different wavelengths.

[0088] In one embodiment, the fiber optic assembly unit further includes a first reflector configured to reflect laser beams projected from the plurality of microlenses to the plurality of bandpass filters; and a second reflector configured to reflect laser beams passing through the plurality of bandpass filters. In another embodiment, the plurality of grating couplers includes a grating coupler array comprising a plurality of rows and columns, wherein the grating couplers in the same row of the plurality of rows have the same structure. In yet another embodiment, the structure of the grating couplers in each row of the plurality of rows differs from the structure of the grating couplers in the other rows of the plurality of rows.

[0089] According to some embodiments of this disclosure, a structure includes: a photonic die including a plurality of grating couplers, wherein the plurality of grating couplers have a first spacing and the plurality of grating couplers have different structures from each other; an electron die to which a signal is coupled; a dielectric region surrounding the electron die and located above the photonic die; a support substrate located above the dielectric region, wherein the support substrate includes a plurality of microlenses, and wherein the plurality of microlenses have a second spacing the same as the first spacing; and an optical fiber assembly unit including an optical fiber configured to receive a laser beam propagating from the plurality of microlenses.

[0090] In one embodiment, the characteristic wavelengths of the plurality of grating couplers are different from each other. In another embodiment, the plurality of grating couplers are aligned in a column, and the photonic die includes a grating coupler array comprising a plurality of columns identical to the columns. In another embodiment, the plurality of grating couplers comprises a plurality of rows, wherein the grating couplers in each of the plurality of rows have the same structure as each other. In another embodiment, the fiber optic assembly unit includes a plurality of optical fibers, each configured to receive a laser beam propagating from a column of grating couplers in the grating coupler array.

[0091] According to one aspect of this application, a method of forming a package is provided, the method comprising: receiving a photonic engine, the photonic engine including: a photonic die including a plurality of grating couplers; and a plurality of microlenses attached to the photonic die, wherein the plurality of grating couplers and the plurality of microlenses are configured to optically couple to each other in a one-to-one correspondence; and attaching an optical fiber assembly unit to the photonic engine, wherein the optical fiber assembly unit includes: an optical fiber; and a laser merging unit configured to optically couple the plurality of microlenses and the optical fiber to each other. In some embodiments, the plurality of grating couplers are aligned in a row, and wherein the plurality of grating couplers have different structures. In some embodiments, the plurality of grating couplers have the same spacing as the plurality of microlenses. In some embodiments, the method of forming a package further comprises: bonding an electron die over the photonic die; and after bonding the electron die to the photonic die, performing a gap-filling process to form a gap-filling region surrounding the electron die. In some embodiments, the method of forming a package further comprises: after forming the gap-filling region, forming a plurality of transparent regions in the gap-filling region and the plurality of transparent regions overlapping the plurality of grating couplers. In some embodiments, attaching multiple microlenses includes attaching a support substrate over the photonic die, wherein the support substrate includes multiple microlenses. In some embodiments, the fiber optic assembly unit includes multiple bandpass filters configured to filter laser beams of different wavelengths. In some embodiments, the fiber optic assembly unit includes: a first reflector configured to reflect laser beams projected from the multiple microlenses, wherein the first reflector reflects the laser beams to the multiple bandpass filters; and a second reflector configured to reflect laser beams that have passed through the multiple bandpass filters.

[0092] According to another aspect of this application, a method of forming a package is provided, the method comprising: forming a photonic die, the photonic die including a plurality of grating couplers, wherein the characteristic wavelengths of the plurality of grating couplers are different from each other, and the plurality of grating couplers have a first spacing; bonding an electron die to the photonic die; forming a gap-filling region adjacent to and above the electron die; and attaching a support substrate to the gap-filling region, wherein the support substrate includes a plurality of microlenses, and wherein the plurality of microlenses have a second spacing the same as the first spacing. In some embodiments, the method of forming the package further includes attaching an optical fiber assembly unit to the support substrate, wherein the optical fiber assembly unit is configured to combine laser beams propagating from the plurality of grating couplers into an optical fiber in the optical fiber assembly unit. In some embodiments, the optical fiber assembly unit includes: an optical fiber; and a laser combining unit configured to couple the plurality of microlenses and fiber optics to each other. In some embodiments, the laser combining unit includes a plurality of bandpass filters configured to filter laser beams with different wavelengths. In some embodiments, the fiber optic assembly unit further includes: a first reflector configured to reflect a laser beam projected from a plurality of microlenses to a plurality of bandpass filters; and a second reflector configured to reflect a laser beam passing through the plurality of bandpass filters. In some embodiments, the plurality of grating couplers includes: a grating coupler array comprising a plurality of rows and a plurality of columns, wherein the grating couplers in the same row of the plurality of rows have the same structure. In some embodiments, the structure of the grating couplers in each row of the plurality of rows differs from the structure of the grating couplers in the other rows of the plurality of rows.

[0093] According to another aspect of this application, a package is provided comprising: a photonic die including a plurality of grating couplers, wherein the plurality of grating couplers have a first spacing and the plurality of grating couplers have different structures from each other; an electron die to which a signal is coupled; a dielectric region surrounding the electron die and located above the photonic die; a support substrate located above the dielectric region, wherein the support substrate includes a plurality of microlenses, and wherein the plurality of microlenses have a second spacing identical to the first spacing; and an optical fiber assembly unit including optical fibers configured to receive laser beams propagating from the plurality of microlenses. In some embodiments, the characteristic wavelengths of the plurality of grating couplers are different from each other. In some embodiments, the plurality of grating couplers are aligned in columns, and the photonic die includes a grating coupler array comprising a plurality of columns identical to the columns. In some embodiments, the plurality of grating couplers comprise a plurality of rows, and wherein the grating couplers in each of the plurality of rows have the same structure as each other. In some embodiments, the optical fiber assembly unit includes a plurality of optical fibers, each optical fiber configured to receive a laser beam propagating from a column of grating couplers in the grating coupler array.

[0094] The foregoing has outlined features of several embodiments to enable those skilled in the art to better understand aspects of this disclosure. Those skilled in the art should understand that they can readily use this disclosure as a basis to design or modify other operations and structures for implementing the same purposes and / or achieving the same advantages as the embodiments described herein. Those skilled in the art should also recognize that such equivalent constructions do not depart from the spirit and scope of this disclosure, and that various changes, substitutions, and alterations can be made to them herein without departing from the spirit and scope of this disclosure.

Claims

1. A method of forming a package, comprising: Receive photonic engine, the photonic engine comprising: Photonic chip, including multiple grating couplers; and Multiple microlenses are attached to the photonic chip, wherein the multiple grating couplers and the multiple microlenses are configured to be optically coupled to each other in a one-to-one correspondence; and The fiber optic assembly unit is attached to the photonic engine, wherein the fiber optic assembly unit includes: Fiber optics; and The laser merging unit is configured to couple the plurality of microlenses and the fiber optics together.

2. The method according to claim 1, wherein, The plurality of grating couplers are aligned in a column, and the plurality of grating couplers have different structures.

3. The method according to claim 1, wherein, The plurality of grating couplers have the same spacing as the plurality of microlenses.

4. The method according to claim 1, further comprising: The electron die is attached above the photonic die; as well as After the electron die is bonded to the photonic die, a gap filling process is performed to form a gap filling region surrounding the electron die.

5. The method according to claim 4, further comprising: After forming the gap-filling region, a plurality of transparent regions are formed in the gap-filling region and the plurality of transparent regions overlap with the plurality of grating couplers.

6. The method according to claim 1, wherein, Attaching the plurality of microlenses includes attaching a support substrate above the photonic die, wherein the support substrate includes the plurality of microlenses.

7. The method according to claim 1, wherein, The fiber optic assembly unit includes multiple bandpass filters configured to filter laser beams with different wavelengths.

8. The method according to claim 7, wherein, The optical fiber assembly unit includes: A first reflector is configured to reflect a laser beam projected from the plurality of microlenses, wherein the first reflector reflects the laser beam to the plurality of bandpass filters; and A second reflector is configured to reflect the laser beam that has passed through the plurality of bandpass filters.

9. A method of forming a package, comprising: A photonic chip is formed, the photonic chip including a plurality of grating couplers, wherein the characteristic wavelengths of the plurality of grating couplers are different from each other, and the plurality of grating couplers have a first spacing; The electron die is bonded to the photonic die; A gap-filling region is formed next to the electron die and above the photonic die; and A support substrate is attached to the gap-filling region, wherein the support substrate includes a plurality of microlenses, and wherein the plurality of microlenses have a second spacing that is the same as the first spacing.

10. A package comprising: A photonic chip includes multiple grating couplers, wherein the multiple grating couplers have a first spacing and the multiple grating couplers have different structures from each other; Electronic chip, signal coupled to the photonic chip; A dielectric region surrounds the electron die and is located above the photonic die; A supporting substrate, located above the dielectric region, wherein the supporting substrate includes a plurality of microlenses, and wherein the plurality of microlenses have a second spacing the same as the first spacing; and An optical fiber assembly unit includes an optical fiber configured to receive a laser beam propagating from the plurality of microlenses.

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