Optical fiber array unit structure

Abstract

An optical fiber array unit structure comprises an optical fiber array unit, a passive optical element structure and a carrier plate. The optical fiber array unit includes an optical fiber holder that holds an optical fiber. The passive optical element structure includes a reflective layer and a lens layer. The reflective layer includes a reflector adjacent to the optical fiber. The lens layer includes a silicon lens adjacent to the reflector. The carrier plate is configured to support the fiber array unit and the passive optical element structure. The optical fiber array unit and the passive optical element structure are adjacent to each other. The lens layer is located between the reflecting layer and the carrier plate.

Description

Technical Field

[0001] An embodiment of the utility model relates to an optical fiber array unit structure. Background Art

[0002] In recent years, due to the increasing use of optical fiber-related signal transmission applications, the application of optical signaling and processing has begun to increase.

[0003] Optical signaling and processing are often combined with electrical signaling and processing to provide sophisticated applications. For example, optical fibers can be used for long-distance signal transmission, while electrical signals can be used for short-distance signal transmission, processing, and control. Consequently, devices integrating optical and electronic components are used for conversion between optical and electrical signals, as well as for processing both. A package (also known as a photonic package) can therefore include a photonic die containing optical devices and an electronic die containing electronic devices.

[0004] A fiber array unit (FAU) typically has multiple grooves, each of which holds an optical fiber. The FAU can be used to optically couple the optical fibers to an optical coupler within a photonic die within a photonic package. Optical adhesive can be used to attach the FAU to the photonic package. After dispensing the optical adhesive between the FAU and the photonic package, the adhesive can be cured, for example, by ultraviolet (UV) curing. Utility Model Content

[0005] The purpose of the present invention is to provide an optical fiber array unit structure to solve at least one of the above problems.

[0006] Some embodiments of the present invention provide a fiber array unit (FAU) structure. The fiber array unit structure includes a fiber array unit, a passive optical component structure, and a carrier board. The fiber array unit includes a fiber holder that holds a plurality of optical fibers. The passive optical component structure includes a reflective layer and a lens layer. The reflective layer includes a plurality of reflectors, wherein the reflectors are adjacent to the optical fibers. The lens layer includes a plurality of silicon lenses, wherein the silicon lenses are adjacent to the reflectors. The carrier board is configured to support the fiber array unit and the passive optical component structure. The fiber array unit and the passive optical component structure are adjacent to each other, and the lens layer is located between the reflective layer and the carrier board.

[0007] According to one embodiment of the present invention, the optical fiber holder includes a plurality of grooves formed on a lower surface of the optical fiber holder to hold the plurality of optical fibers, wherein the plurality of optical fibers are located between the optical fiber holder and the carrier plate.

[0008] According to one embodiment of the present invention, the reflective layer further includes a dielectric layer, and the plurality of reflectors are embedded in the dielectric layer.

[0009] According to one embodiment of the present invention, the reflective layer further includes a plurality of waveguides and a plurality of optical splitters embedded in the dielectric layer.

[0010] According to one embodiment of the present invention, the lens layer is a silicon lens layer, and the lens layer also includes a plurality of silicon pillars and a gap filling material, and the gap filling material fills the gaps between the plurality of silicon pillars and between the plurality of silicon pillars and the plurality of silicon lenses.

[0011] According to one embodiment of the present invention, the passive optical element structure further includes a glass cover disposed on a side of the reflective layer opposite to the lens layer.

[0012] According to one embodiment of the present invention, the passive optical element structure further includes a passivation layer disposed on a side of the reflective layer opposite to the lens layer.

[0013] According to one embodiment of the present invention, it also includes: a first optical adhesive, arranged between the passive optical element structure and the adjacent side wall of the optical fiber array unit; and a second optical adhesive, arranged between the passive optical element structure and the bottom surface of the optical fiber array unit and the top surface of the carrier board.

[0014] According to one embodiment of the present invention, the passive optical element structure is bonded to a top surface of the carrier via a bonding layer, and the optical fiber array unit is attached to the top surface of the carrier via an optical adhesive, wherein the optical adhesive further extends into the gap between the passive optical element structure and adjacent side walls of the plurality of optical fibers.

[0015] According to one embodiment of the present invention, the carrier has a recess formed on the top surface of the carrier to accommodate the plurality of optical fibers. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The following detailed description, taken in conjunction with the accompanying drawings, will provide a better understanding of the concepts of the present invention. It should be noted that, in accordance with standard industry practice, the various features in the drawings are not necessarily drawn to scale. In fact, the dimensions of various features may be arbitrarily enlarged or reduced for clarity of illustration.

[0017] Figure 1 A cross-sectional view showing an integrated fiber array unit (FAU) structure according to some embodiments.

[0018] Figure 2A and Figure 2B Display according to some embodiments Figure 1 A cross-sectional view of a fiber array unit (FAU) in an integrated fiber array unit structure.

[0019] Figures 3 to 11 shows the formation according to some embodiments Figure 1 Cross-sectional view of the intermediate steps of the integrated optical fiber array unit structure.

[0020] Figure 12 A cross-sectional view illustrating an integrated optical fiber array unit structure according to some embodiments.

[0021] Figure 13 A cross-sectional view illustrating an integrated optical fiber array unit structure according to some embodiments.

[0022] Figures 14 to 19 shows the formation according to some embodiments Figure 13 Cross-sectional view of the intermediate steps of the integrated optical fiber array unit structure.

[0023] Figure 20 A cross-sectional view illustrating an integrated optical fiber array unit structure according to some embodiments.

[0024] Figure 21 A cross-sectional view illustrating an integrated optical fiber array unit structure according to some embodiments.

[0025] Figures 22 to 25 shows the formation according to some embodiments Figure 21 Cross-sectional view of the intermediate steps of the integrated optical fiber array unit structure.

[0026] Figure 26 A cross-sectional view shows a portion of a semiconductor package according to some embodiments.

[0027] The reference numerals are as follows:

[0028] 100, 200, 300, 400, 500: Integrated fiber array unit (FAU) structure / fiber array unit structure

[0029] 101: Silicon substrate

[0030] 101': Thinned silicon substrate

[0031] 102: Fiber Array Unit (FAU)

[0032] 104: Fiber Optic Fixer

[0033] 106: Fiber Optic

[0034] 110,110',110":Light guide structure / passive optical element structure

[0035] 111: Dielectric materials

[0036] 111A: Open

[0037] 112: Reflection layer

[0038] 113:Reflective coating

[0039] 114:Reflector

[0040] 115: Dielectric material

[0041] 116: dielectric layer

[0042] 118: Lens layer / silicon lens layer

[0043] 120: Lens structure / silicon lens

[0044] 122:Silicon column

[0045] 123: Gap

[0046] 124: Dielectric material / gap filling material

[0047] 125: bonding layer

[0048] 126: Glass cover

[0049] 127: Draw a line

[0050] 128: Optical adhesive

[0051] 130:Carrier board

[0052] 132: Optical adhesive

[0053] 136: Waveguide

[0054] 138:Spectrum Splitter

[0055] 140: Protective material / passivation layer

[0056] 142: bonding layer

[0057] 144: Edge area / fiber placement area

[0058] 146: concave part

[0059] 147: Draw a line

[0060] 148: Thin glass sheet

[0061] 148':Glass substrate

[0062] 150: L-shaped carrier

[0063] 152: Optical adhesive

[0064] 154: Draw a line

[0065] 600:Semiconductor packaging

[0066] 610: packaging substrate

[0067] 620: Photonic Packaging

[0068] 621: Electronic bare chips

[0069] 622: Photonic Die

[0070] 623:Electrical connector

[0071] 624: bottom fill layer

[0072] 630:Metal cover

[0073] 631: Open

[0074] 632: Adhesive

[0075] 634: Thermal interface material

[0076] 636: Optical adhesive

[0077] D: Depth

[0078] G: Gap size

[0079] H: Height

[0080] S: Light path

[0081] T1, T2, T3, T4: thickness

[0082] θ: angle

[0083] X, Y, Z: axis DETAILED DESCRIPTION

[0084] The following disclosure provides many different embodiments or examples for implementing different features of the embodiments of the present invention. Specific examples of components and configurations are described below to simplify the description of the embodiments of the present invention. Of course, these specific examples are for illustrative purposes only and are not intended to limit the embodiments of the present invention. For example, in the following description, it is mentioned that a first feature is formed on or above a second feature, which means that it may include an embodiment in which the first feature and the second feature are in direct contact, and may also include an embodiment in which an additional feature is formed between the first feature and the second feature, so that the first feature and the second feature may not be in direct contact. In addition, the present invention may repeat reference symbols and / or letters in various examples. This repetition is for the purpose of simplicity and clarity, and does not itself limit the relationship between the various embodiments and / or configurations described.

[0085] Furthermore, spatially relative terms, such as "below," "beneath," "lower," "above," "upper," and the like, may be used herein to describe the relationship of one element or feature to another element or feature illustrated in the drawings. These spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the drawings. The system may be oriented differently (rotated 90 degrees or at other orientations), and the spatially relative terms used herein should be interpreted accordingly.

[0086] According to some embodiments of the present invention, an integrated fiber array unit (FAU) structure and a method for forming the same are provided. The disclosed integrated fiber array unit (FAU) structure integrates a fiber array unit (FAU) that holds an optical fiber with a light guide structure. The light guide structure may include various passive optical components, such as reflectors, lenses, waveguides, and / or beam splitters, to help guide the optical beam from the optical fiber to the photonic package and / or modify the optical beam. This eliminates the need for additional passive optical components outside of the fiber array unit structure, helping to reduce the package size of the semiconductor package / system. In some embodiments, the passive optical components are embedded within the light guide structure and are not exposed. This reduces the risk of damage to the passive optical components during assembly of the integrated fiber array unit structure and the photonic package. Consequently, the product yield and reliability of the integrated fiber array unit structure are also improved. In some embodiments, the integrated fiber array unit structure further includes a carrier plate or L-shaped support to support the fiber array unit and the light guide structure, thereby improving the structural stability of the integrated fiber array unit structure.

[0087] The embodiments discussed herein provide examples of the subject matter of the present invention, and those skilled in the art will readily appreciate that modifications may be made while remaining within the intended scope of the various embodiments. In the various views and illustrative embodiments, like reference symbols are used to indicate like elements. Although method embodiments may be discussed as being performed in a particular order, other method embodiments may be performed in any logical order.

[0088] Figure 1 A cross-sectional view of an integrated fiber array unit (FAU) structure 100 is shown according to some embodiments. The integrated fiber array unit structure 100 (hereinafter referred to as the fiber array unit structure 100) can be used to optically couple the optical fiber 106 to the photonic package 620 (e.g., see Figure 26 ) within the photonic die (e.g., a grating coupler or an edge coupler), which will be described in more detail below. Figure 1 As shown, the fiber array unit structure 100 consists of three parts: a fiber array unit (FAU) 102 holding a plurality of optical fibers 106, a light guide structure 110, and a carrier 130. During assembly, the fiber array unit 102 and the light guide structure 110 are connected using optical glue 128, and they are further connected to the carrier 130 via optical glue 132.

[0089] The fiber array unit 102 includes a fiber holder 104 for holding a plurality of optical fibers 106 . Figure 2A and Figure 2B A cross-sectional view of a fiber holder 104 is shown holding an optical fiber 106 according to some embodiments. Figure 2A and Figure 2B As shown, the fiber holder 104 can have a plurality of grooves (eg, recesses) formed on a lower surface thereof, wherein each groove holds an optical fiber 106 therein. Figure 2A and Figure 2B The grooves shown in FIG. 1 are merely examples, and fiber holder 104 may have a different number of grooves than shown (corresponding to the number of optical fibers 106 held), or the grooves may have different shapes or different sizes than shown. Fiber holder 104 may be formed from one or more materials, such as silicon (e.g., bulk silicon), silicon oxide, ceramic, glass, polymer, metal, metal alloy, or the like, or combinations thereof. In some cases, the end of each optical fiber 106 distal from fiber holder 104 may be coupled to an optical interconnect (e.g., an MT ferrule, not shown), which is coupled to a light source (not shown). In some embodiments, optical fibers 106 may be secured within corresponding grooves of fiber holder 104 using a glue (not shown), such as an adhesive, optical glue, or the like.

[0090] In some embodiments, as Figure 2B As shown, a polishing process can be performed to remove the bottom portion of the optical fiber 106. The polishing process can include a chemical-mechanical polishing (CMP) process, a grinding process, or other suitable polishing process. In some embodiments, after performing the polishing process, the bottom surface of the optical fiber 106 is substantially flat and coplanar. In this way, polishing the optical fiber 106 can reduce the overall height of the optical fiber 106 and the optical fiber array unit 102.

[0091] In some embodiments, the fiber array unit 102 can be oriented within the fiber array unit structure 100 such that the optical fiber 106 is adjacent to the reflective layer 112 within the light guide structure 110, as shown in FIG. Figure 1 This allows the light beam provided by the optical fiber 106 to be reflected (eg, redirected) by the corresponding reflector 114 within the reflective layer 112 to the photonic package 620 (eg, see Figure 26 ),like Figure 1 As shown in the light path S (indicated by the dotted line with arrows).

[0092] According to some embodiments, the light guide structure 110 (also referred to as the passive optical element structure 110) includes a reflective mirror layer or a reflective layer 112, a lens layer 118, and a glass cover 126. Figure 1 As shown, the cover glass 126, the reflective layer 112, and the lens layer 118 are arranged in sequence along a vertical direction (e.g., the Z direction), with the cover glass 126 at the top, the lens layer 118 at the bottom, and the reflective layer 112 between the cover glass 126 and the lens layer 118. In this way, the cover glass 126 provides protection for the reflective layer 112 and the lens layer 118 below.

[0093] In some embodiments, the reflective layer 112 includes a plurality of reflectors 114 embedded in one or more dielectric layers 116. The reflectors 114 can be a single layer of metal or a multilayer structure including multiple sublayers, which will be described in more detail below. As described above, the reflectors 114 can be formed to redirect light from the optical fibers 106 of the optical fiber array unit 102. For example, each reflector 114 can form an angle θ with a horizontal plane (e.g., an XY plane) (in the case where the optical fibers 106 are arranged horizontally) so that the direction of travel of the light from the optical fibers 106 can be changed from horizontal to vertically downward (i.e., toward the lens layer 118), as shown in FIG. Figure 1 , as shown in the optical path S in FIG. In some embodiments, the angle θ may be approximately 45 degrees, although other angles may also be used. In a plan view (not specifically shown), the reflectors 114 may be aligned with the optical fibers 106 in a one-to-one manner (e.g., one reflector 114 and one corresponding optical fiber 106 are aligned in a line along the X direction).

[0094] It should be noted that the reflective layer 112 having the reflector 114 embedded therein is in contrast to the reflective layer having the reflector formed therein and exposed on the end face of the reflective layer. Embedding the reflector 114 within the reflective layer 112 (e.g., the dielectric layer 116) can reduce the connection between the optical fiber array unit structure 100 and the photonic package 620 (e.g., see FIG. Figure 26 ) risk of damaging the reflector 114 during assembly.

[0095] In some embodiments, the lens layer 118 is made of silicon and is therefore also referred to as a silicon lens layer 118. The silicon lens layer 118 includes a plurality of silicon lenses 120 adjacent to the plurality of reflectors 114 (due to viewing angle limitations, Figure 1 Only one silicon lens 120 and a corresponding reflector 114 are shown in the figure to allow the reflected light from the reflector 114 to pass through the corresponding silicon lens 120. The silicon lens 120 can help focus the light beam, thereby adjusting the light spot size.

[0096] In some embodiments, as Figure 1 As shown, the silicon lens layer 118 further includes a plurality of silicon pillars (or walls) 122. The silicon pillars 122 can be evenly distributed throughout the lens layer 118, which helps to avoid stress concentration problems in the lens layer 118. Gaps 123 (not shown) are formed between the silicon pillars 122. Figure 1 shown in Figure 8 ) may allow light (eg, UV light) to pass through to cure the optical glue 636 used to attach the fiber array unit structure 100 to the photonic package 620 during a UV curing process (eg, see Figure 26 In some cases, the gap size G between adjacent silicon pillars 122 is in a range between about 200 and about 1000 μm, although smaller or larger gap sizes may also be used. In some embodiments, a dielectric material 124 (also referred to as gap filler material 124 ) is formed to fill gaps 123 between silicon pillars 122 .

[0097] The carrier plate 130 is used to mechanically support the fiber array unit 102 and the light guide structure 110 and allows the fiber array unit structure 100 to be attached to the photonic package 620 (see, for example, FIG. 1 ) by, for example, optical glue 636. Figure 26 ). The carrier 130 may include components suitable for use in the photonic package 620 (see, for example, Figure 26 ) and the optical fiber 106. In some embodiments, the carrier 130 includes a UV-transparent material (e.g., glass or sapphire) to allow UV light to pass through during the UV curing process of the optical adhesive 636. In some cases, the thickness T1 of the carrier 130 ranges between about 200 μm and about 500 μm, although other thicknesses may also be used.

[0098] Figures 3 to 11 A cross-sectional view showing intermediate steps in forming an integrated optical fiber array unit structure 100 according to some embodiments. Figure 3 In the embodiment, a silicon substrate 101 is provided. In the embodiment, the silicon substrate 101 includes a scribe line 127 (eg, see Figure 9) is separated by a plurality of component regions. A dielectric material 111 is formed on the silicon substrate 101. In some embodiments, the dielectric material 111 is formed of a dielectric material (e.g., silicon oxide or silicon nitride) that is substantially transparent to light of a wavelength suitable for transmitting optical signals. The dielectric material 111 can be formed by any acceptable deposition process, such as chemical vapor deposition (CVD), physical vapor deposition (PVD), atomic layer deposition (ALD), spin coating, lamination, etc., or a combination thereof. Other suitable dielectric materials formed by any acceptable process can also be used.

[0099] Next, in Figure 4 In the dielectric material 111, a reflector 114 is to be formed (for example, see Figure 5 ) is formed at a position of the dielectric material 111. The opening 111A can extend to a specific depth of the dielectric material 111 or directly pass through the dielectric material 111. The sidewalls of each opening 111A can form an angle θ with the horizontal plane (as shown by the dotted line) so that the subsequently formed reflector 114 also forms an angle θ with the horizontal plane. In some cases, the angle θ can be about 45 degrees, but other angles can also be used. The opening 111A can be formed by acceptable photolithography and etching techniques, for example, by forming and patterning a photoresist and then performing an etching process using the patterned photoresist as an etching mask. The etching process can include, for example, an anisotropic wet etching process. Other processes suitable for forming the opening 111A can also be used.

[0100] Continue to refer Figure 4 , a reflective coating 113 is conformally formed on the sidewalls and bottom of each opening 111A. In some embodiments, the reflective coating 113 is a single layer of metal, wherein the metal material used includes gold (Au), silver (Ag), copper (Cu), aluminum (Al), titanium (Ti), tantalum (Ta), etc., their alloys or combinations thereof. Alternatively, the reflective coating 113 is a multilayer structure including a plurality of sublayers, wherein each sublayer can be formed of the above-mentioned metal materials or other suitable dielectric materials (for example, silicon oxide (SiO2), hafnium oxide (HfO2), tantalum oxide (Ta2O5), titanium oxide (TiO2), silicon nitride (SiN), amorphous silicon, etc.). The reflective coating 113 can be formed using any acceptable process, such as CVD, PVD, ALD or other suitable deposition processes. In some cases, the thickness of the reflective coating 113 can be about 1000 nm. and about 100 μm, although other thicknesses may also be used.

[0101] In some embodiments, a mask layer (not shown) may be formed on the upper surface of the dielectric material 111 to prevent the reflective coating 113 from being formed on the upper surface while exposing the openings 111A. This allows the reflective coating 113 to be formed only on the surface of each opening 111A. After the reflective coating 113 is formed, the mask layer may be removed using a suitable removal process.

[0102] Next, in Figure 5 In the embodiment, dielectric material 115 is formed over dielectric material 111 and reflective coating 113 in opening 111A. The material and formation method of dielectric material 115 may be similar or the same as the material and formation method of dielectric material 111 described previously. A planarization process (e.g., a CMP process, a grinding process, etc., not shown) may then be performed on dielectric material 115 to thin and planarize dielectric material 115. In some embodiments, after the planarization process is performed, the top surfaces of dielectric material 111 and dielectric material 115 may be substantially flush or coplanar, as shown in FIG. Figure 5 Alternatively, after the planarization process, a portion of dielectric material 115 may remain on dielectric material 111. Reflective coating 113 embedded in dielectric material 111 and dielectric material 115 (collectively referred to as dielectric layer 116) forms reflector 114. Thus, reflective layer 112 including embedded reflector 114 is formed above silicon substrate 101.

[0103] Next, in Figure 6 In the embodiment of the present invention, a glass cover 126 is bonded to the side of the reflective layer 112 opposite to the silicon substrate 101. The glass cover 126 can be bonded to the reflective layer 112 via a bonding layer 125. In some cases, the bonding layer 125 may include a material suitable for dielectric-to-dielectric bonding. For example, the bonding layer 125 can be formed of a dielectric material or include a dielectric material, such as silicon oxide (SiO2), SiN, SiON, SiOCN, SiC, SiCN, etc., or a combination thereof, and the bonding layer 125 can be formed on the glass cover 126 or the reflective layer 112 using high-density plasma chemical vapor deposition (HDPCVD), plasma enhanced chemical vapor deposition (PECVD), CVD, low-pressure chemical vapor deposition (LPCVD), ALD, etc. Other suitable dielectric or bonding materials formed by any acceptable process may also be used.

[0104] Next, in Figure 7 In the embodiment of the present invention, a thinning process (e.g., a CMP process, a grinding process, an etching process, or other suitable process) is used to thin the silicon substrate 101. The thinned silicon substrate 101' can have a thickness T2 (e.g., about 30 μm to about 70 μm) so that the reflected light from the reflector 114 can successfully pass through it (i.e., avoiding or reducing light reflection). In some cases, the thinned silicon substrate allows the light guide structure 110 and the optical fiber array unit 102 to be connected after the connection (e.g., see Figure 10 ) The bottom surface of the light guide structure 110 (eg, the bottom surface of the lens layer 118) is substantially flush or coplanar with the bottom surface of the optical fiber array unit 102 (eg, the bottom surface of the optical fiber 106), although the invention is not limited thereto.

[0105] Continue to refer Figure 7 , a lens structure 120, which may also be referred to as a silicon lens 120, is then formed on the bottom surface of the thinned silicon substrate 101' (e.g., recessed therefrom). The silicon lens 120 may be located adjacent to the reflector 114 so that reflected light from one reflector 114 can pass through the corresponding silicon lens 120, as described above. The silicon lens 120 may be formed using acceptable photolithography and etching techniques. For example, in some embodiments, a hard mask layer (e.g., a nitride layer, etc., not shown) may be formed on the bottom surface of the thinned silicon substrate 101' and patterned, wherein the pattern of the hard mask layer corresponds to the silicon lens 120. The patterned hard mask layer may then be used as an etching mask to perform an etching process on the thinned silicon substrate 101' to form the silicon lens 120. The etching process may be a dry etching process or a wet etching process, which may include an isotropic etching process. In some embodiments, more than one photolithography and etching process may be used to form the silicon lens 120. After forming the silicon lens 120 , the hard mask layer may be removed from the thinned silicon substrate 101 ′ using an ashing process or other acceptable etching process.

[0106] Next, in Figure 8In the embodiment, a plurality of silicon pillars 122 are uniformly formed in the region of the thinned silicon substrate 101' except for the silicon lens 120, wherein gaps 123 are provided between the silicon pillars 122. The silicon pillars 122 and the gaps 123 can be formed using acceptable photolithography and etching techniques. For example, in some embodiments, a photoresist layer (not shown) can be formed on the bottom surface of the thinned silicon substrate 101' and patterned, wherein the pattern of the photoresist layer corresponds to the gaps 123. The patterned photoresist layer can then be used as an etching mask to perform an etching process on the thinned silicon substrate 101' to form the gaps 123. The etching process can include, for example, an isotropic dry etching process. Other processes suitable for forming the gaps 123 can also be used. After the gaps 123 are formed, the photoresist layer can be removed using a suitable removal process. The remaining portion of the thinned silicon substrate 101' forms the silicon pillars 122.

[0107] Next, in Figure 9 In the embodiment of the present invention, a dielectric material 124 (also referred to as gap filling material 124) is deposited on the bottom surface of the thinned silicon substrate 101' and fills the gaps 123 between the silicon pillars 122 (and also fills the gaps above the lens surface of the silicon lens 120). The dielectric material 124 can be formed of silicon oxide, silicon nitride, polymer, etc., or a combination thereof, and can be formed by CVD, PVD, ALD, or other suitable deposition processes. Other suitable dielectric materials formed by any acceptable process can also be used. A planarization process such as a CMP process, a grinding process, etc. can then be used to planarize the dielectric material 124. In some embodiments, after the planarization process is performed, the bottom surfaces of the silicon pillars 122 and the dielectric material 124 can be substantially flush or coplanar. Thus, the lens layer 118 including the silicon lens 120 and the silicon pillars 122 is formed below the reflective layer 112.

[0108] Continue to refer Figure 9 , a singulation process is then performed to separate the plurality of light guide structures 110 formed on the same silicon substrate 101 (e.g., a silicon wafer) into a plurality of individual light guide structures 110 (for simplicity, only one light guide structure 110 is shown). In some embodiments, the singulation process may include sawing the scribe lines 127 using a mechanical saw. Other suitable singulation processes may also be used. In some embodiments, after the singulation process, the reflectors 114 are embedded within the reflective layer 112 (i.e., not exposed from the sidewalls of the reflective layer 112), so that they can be protected. The silicon lens 120 may also be protected by the dielectric material 124 and not exposed. In this way, the risk of damaging the passive optical elements of the light guide structure 110 (e.g., including the reflector 114 and the silicon lens 120) during subsequent assembly steps can be reduced.

[0109] Next, in Figure 10In the embodiment, after the light guide structure 110 is formed, the optical glue 128 is used to connect the optical fiber array unit 102 and the light guide structure 110. According to some embodiments, before connecting the optical fiber array unit 102 and the light guide structure 110, an alignment process of aligning the optical fibers 106 of the optical fiber array unit 102 and the reflectors 114 of the light guide structure 110 laterally and vertically can be performed. After the alignment process is performed, the optical glue 128 is dispensed into the gap between the optical fiber array unit 102 and the adjacent sidewalls of the light guide structure 110. The optical glue 128 can further extend into the gap between the optical fibers 106 and the reflective layer 112 to improve the optical coupling between the optical fibers 106 and the reflective layer 112 (e.g., the reflector 114). The optical glue 128 can be applied in liquid form and then cured (e.g., by UV curing).

[0110] Next, in Figure 11 In the process, use optical adhesive 132 to Figure 10 The resulting structure is connected to the carrier 130 to form the previously referenced Figure 1 The integrated fiber array unit (FAU) structure 100 is described. The carrier 130 can be used as a flat interface of the fiber array unit structure 100 to connect to the photonic package 620 (see, for example, Figure 26 ), which helps to improve the physical and optical coupling between the fiber array unit structure 100 and the photonic package 620. Similarly, the optical glue 132 can be applied in liquid form and then cured (for example, by UV curing).

[0111] It should be understood that since the integrated optical fiber array unit structure 100 of the above embodiment integrates the optical fiber array unit 102 and the passive optical components (e.g., the reflector 114 and the silicon lens 120), its optical performance is improved. In addition, this also eliminates the need for additional passive optical components outside the optical fiber array unit structure, thereby reducing the need for these optical components in the semiconductor package 600 (e.g., see Figure 26 ) area. Therefore, the package size of the semiconductor package 600 can be reduced.

[0112] In other embodiments, various other passive optical elements may be embedded in the reflective layer 112 to improve the optical performance of the integrated optical fiber array unit structure. For example, Figure 12 A cross-sectional view of an integrated optical fiber array unit structure 200 according to some embodiments is shown. The integrated optical fiber array unit structure 200 is similar to Figures 1 to 11 The integrated optical fiber array unit structure 100 is further embedded in the reflective layer 112 except that a plurality of waveguides 136 and optical splitters 138 are further embedded in the reflective layer 112. Figure 12As shown, when the waveguide 136 and the optical splitter 138 are inserted into the reflective layer 112, the positions of the reflector 114 and the silicon lens 120 are also changed. It should be understood that the positions of the waveguide 136, the reflector 114 and the silicon lens 120 depend on the photonic package 620 (for example, see Figure 26 ) within the optical coupler.

[0113] The waveguides 136 are laterally positioned between the reflectors 114 and the optical fibers 106 of the fiber array unit 102 to help guide light. For example, in a plan view (not specifically shown), the waveguides 136 are elongated and parallel to each other, and the waveguides 136 can be aligned with the reflectors 114 in a one-to-one manner (e.g., one waveguide 136 and one corresponding reflector 114 are arranged in a line along the X direction) and can be aligned with the optical fibers 106 in a one-to-one manner (e.g., one waveguide 136 and one corresponding optical fiber 106 are arranged in a line along the X direction). The waveguides 136 can also be positioned so that the fiber core of each optical fiber 106 is aligned in a cross-sectional view (e.g., see FIG. Figure 12 ) are aligned with the corresponding waveguide 136 (ie, they are at the same vertical height) to allow optical coupling between the optical fiber 106 and the corresponding waveguide 136.

[0114] In some embodiments, each waveguide 136 may have a larger dimension (eg, height H, as shown) at its end adjacent to the corresponding optical fiber 106. Figure 12 ) to match the size (e.g., diameter) of the fiber core, thereby increasing the optical coupling efficiency between the optical fiber 106 and the corresponding waveguide 136. The height H of the waveguide 136 can be increased by increasing the number of layers and / or thickness of the waveguide 136.

[0115] Due to the difference in refractive index between the waveguide 136 and the surrounding dielectric layer 116, the waveguide 136 exhibits high internal reflection, which substantially confines light within the waveguide 136, depending on the wavelength of the light and the refractive index of the respective materials. In some embodiments, the refractive index of the material of the waveguide 136 is higher than the refractive index of the material of the dielectric layer 116. For example, the waveguide 136 may comprise silicon nitride, while the dielectric layer 116 may comprise silicon oxide. However, other suitable materials for the waveguide 136 and the dielectric layer 116 may also be used.

[0116] Waveguide 136 can be formed by any acceptable deposition process, such as spin coating, CVD, lamination, or a combination thereof. In some embodiments, waveguide 136 is a nitride (e.g., silicon nitride) waveguide formed by patterning a silicon nitride layer using acceptable photolithography and etching processes. It should be noted that silicon nitride has a higher dielectric constant than silicon, and thus nitride waveguides can have greater internal confinement of light than silicon waveguides. This can also make the performance or leakage of nitride waveguides less sensitive to process variations, less sensitive to dimensional uniformity, and less sensitive to surface roughness (e.g., edge roughness or line width roughness). Further details of waveguide 136 will not be discussed here.

[0117] The optical splitter 138 can be integrated with the waveguide 136 and can be formed together with the waveguide 136 (for example, the optical splitter 138 and the waveguide 136 can share some of the same structures and process steps). The optical splitter 138 can be optically coupled to the waveguide 136 and can interact with the optical signal within the waveguide 136. In the present embodiment, each optical splitter 138 is, for example, a polarization beam splitter (PBS), which allows a light beam with a specific polarization direction to pass through and reflects another light beam with a specific polarization direction. For example, the polarization beam splitter 138 allows P-polarized light to pass through and reflects S-polarized light, but the present invention is not limited to this. In this way, the light beam from the optical fiber 106 can be converted into a specific polarization direction by the polarization beam splitter 138 before reaching the reflector 114. Other structures, configurations or arrangements of the waveguide 136 and / or the optical splitter 138 are also possible and are not limited to Figure 12 Further details of the optical splitter 138 will not be described here. In other embodiments, the optical splitter 138 may be omitted.

[0118] Figure 13 A cross-sectional view of an integrated fiber array unit (FAU) structure 300 is shown according to some embodiments. The integrated fiber array unit structure 300 is similar to Figures 1 to 11 The integrated optical fiber array unit structure 100 is shown in FIG. 1 , except that the light guide structure 110 is replaced by a light guide structure 110′. In the light guide structure 110′ of this embodiment, there is no glass cover 126. Instead, a protective material 140 (also referred to as a passivation layer 140) is formed on the reflective layer 112 for protection. In addition, the light guide structure 110′ is directly bonded to the carrier 130. In this way, the number of assembly steps between the light guide structure 110′ and the optical fiber array unit 102 and the amount of optical adhesive used can be reduced (for example, the optical adhesive can be omitted). Figures 1 to 11In the embodiment of the present invention, the optical glue 128 is used to connect the light guide structure 110 and the optical fiber array unit 102).

[0119] In addition, Figure 13 In the example of FIG, the optical adhesive 132 used to connect the fiber array unit 102 to the carrier board 130 can extend into the gap between the light guide structure 110′ and the adjacent sidewall of the fiber array unit 102 to improve the optical coupling between the optical fiber 106 and the reflective layer 112 (e.g., the reflector 114). In some cases, the optical adhesive 132 can also extend onto the top surface of the protective material 140, which helps to enhance the adhesion between the protective material 140 and the reflective layer 112.

[0120] In some embodiments, a recess 146 is formed on the top surface of the carrier 130 (not shown). Figure 13 shown in Figure 18 The recess 146 may be provided with a recessed portion (e.g., a recessed portion 146) to accommodate the optical fiber 106. This facilitates reducing the height of the optical fiber array unit structure 300. In some cases, the depth D of the recess 146 may be within a range between approximately 0 μm and approximately 50 μm, depending on the diameter of the optical fiber 106 (e.g., the larger the diameter of the optical fiber 106, the greater the depth D of the recess 146). Other depths of the recess 146 may also be used.

[0121] Figures 14 to 19 shows the formation according to some embodiments Figure 13 A cross-sectional view of an intermediate step of the integrated optical fiber array unit structure 300. Figure 14 In the Figure 5 , and then forming a protective material 140 over the reflective layer 112. The protective material 140 may include one or more materials similar to those described above for the dielectric layer 116, such as silicon oxide or silicon nitride, or may include different materials. In some embodiments, the protective material 140 is denser than the dielectric layer 116 and has the function of isolating the optical elements (e.g., the reflector 114) within the dielectric layer 116 from harmful chemicals and gases (e.g., moisture) in the external environment. In such an embodiment, the protective material 140 may be undoped silicate-glass (USG), tetraethoxysilane (TEOS) oxide, or other suitable protective materials.

[0122] Next, in Figure 15 In the embodiment of the present invention, a temporary glass carrier (e.g., the glass cover 126 described above) is bonded to the protective material 140 above the reflective layer 112. The glass cover 126 can be bonded to the protective material 140 via a bonding layer (e.g., the bonding layer 125 described above). The material and formation method of the bonding layer 125 can be referred to. Figure 6 The content described in .

[0123] Next, in Figure 16 In the embodiment, a lens layer 118 including a silicon lens 120 and a silicon pillar 122 is formed below the reflective layer 112. The lens layer 118 can be formed by thinning the silicon substrate 101, forming the silicon lens 120 on the bottom surface of the thinned silicon substrate 101', forming the silicon pillar 122 in the region of the thinned silicon substrate 101' except for the silicon lens 120, and filling the gaps between the silicon pillars 122 with a dielectric material 124, as described above with reference to FIG. Figures 7 to 9 Therefore, details about the lens layer 118 are not described here.

[0124] Next, in Figure 17 In the embodiment, the bonding layer 142 is used to Figure 16 The resulting structure is bonded to the carrier 130. In some cases, the bonding layer 142 may include a material suitable for dielectric-to-dielectric bonding. For example, the bonding layer 142 may be formed of or include a dielectric material, such as silicon oxide (SiO2), SiN, SiON, SiOCN, SiC, SiCN, etc. or a combination thereof, and the bonding layer 142 may be formed on the lens layer 118 or the carrier 130 using CVD, HDPCVD, PECVD, LPCVD, ALD, etc. Other suitable dielectric or bonding materials formed by any acceptable process may also be used. In some embodiments, the material of the bonding layer 142 may be the same as or different from the material of the bonding layer 125. In addition, Figure 17 Also shown is an edge region 144 of the carrier board 130 where the optical fibers 106 of the optical fiber array unit 102 are to be placed. Therefore, the edge region 144 may also be referred to as an optical fiber placement region 144 .

[0125] Next, in Figure 18 In the embodiment of the present invention, a suitable removal process (e.g., a grinding process, an etching process, or other suitable removal process) is used to remove the temporary glass cover 126 and the bonding layer 125 from the protective material 140. Subsequently, another removal process (also referred to as a second removal process) is performed to remove the structural layers (e.g., the protective material 140, the reflective layer 112, the lens layer 118, and the bonding layer 142) on the carrier 130 in the edge region 144. The second removal process may include a grinding process, an etching process, or other suitable removal process. In some embodiments, the second removal process further removes a portion of the carrier 130 in the edge region 144 to form a portion for accommodating the optical fiber 106 (e.g., see Figure 19 ) of the recess 146. As described above, the depth D of the recess 146 is determined by the diameter of the optical fiber 106. In other embodiments, the recess 146 does not exist.

[0126] Continue to refer Figure 18 , a segmentation process is then performed to separate the multiple light guide structures 110' formed on the same silicon substrate 101 into multiple individual light guide structures 110' (for simplicity, only one light guide structure 110' is shown). The carrier 130 located below the light guide structure 110' is also cut through during the segmentation process. In some embodiments, the segmentation process may include sawing the scribe line 147 using a mechanical saw. Other suitable segmentation processes may also be used. In some embodiments, after the segmentation process, the reflector 114 and the silicon lens 120 are embedded in the light guide structure 110' and are not exposed. In this way, the risk of damaging the passive optical elements of the light guide structure 110' (for example, including the reflector 114 and the silicon lens 120) during subsequent assembly steps can be reduced. In some embodiments, after the segmentation process, the recess 146 of the carrier 130 (if present) is adjacent to the light guide structure 110' above the carrier 130.

[0127] Next, in Figure 19 In the embodiment, the optical fiber array unit 102 is connected to the carrier board 130 using optical glue 132 to form the previously referenced Figure 13 The integrated fiber array unit (FAU) structure 300 is described. Similarly, the carrier 130 can be used as a flat interface for the fiber array unit structure 300 to connect to the photonic package 620 (see, for example, Figure 26 ), which helps improve the physical and optical coupling between the fiber array unit structure 300 and the photonic package 620. In some embodiments, after the fiber array unit 102 is placed on the top surface of the carrier 130 (e.g., in the fiber placement area 144) or in the recess 146 of the carrier 130 and the optical fiber 106 is aligned with the reflector 114, the optical glue 132 can be dispensed into the gap between the optical fiber 106 and the carrier 130. As described above, in some cases, the optical glue 132 can also extend into the gap between the light guide structure 110' and the adjacent sidewalls of the fiber array unit 102 or extend onto the top surface of the protective material 140. The optical glue 132 can be applied in liquid form and then cured (e.g., by UV curing).

[0128] Figure 20 A cross-sectional view of an integrated fiber array unit (FAU) structure 400 is shown according to some embodiments. The integrated fiber array unit structure 400 is similar to Figures 13 to 19 The integrated optical fiber array unit structure 300 further includes a plurality of waveguides 136 and optical splitters 138 embedded in the reflective layer 112 of the optical waveguide structure 110'. Figure 12 The waveguide 136 and the beam splitter 138 shown in FIG are the same or similar, so the details regarding the waveguide 136 and the beam splitter 138 will not be repeated here. In other embodiments, the beam splitter 138 may be omitted.

[0129] Figure 21 A cross-sectional view of an integrated fiber array unit (FAU) structure 500 according to some embodiments is shown. The integrated fiber array unit structure 500 consists of three parts: a fiber array unit (FAU) 102 holding a plurality of optical fibers 106, a light guide structure 110", and an L-shaped carrier 150. The fiber array unit 102 is similar to the previously described FAU. Figure 1 、 Figure 2A and Figure 2B The fiber array unit 102 is the same or similar to the one described. During assembly, the fiber array unit 102 and the light guide structure 110 ″ are connected using optical glue 128 , and they are further connected to the L-shaped carrier 150 via optical glue 152 .

[0130] Light guide structure 110" and Figures 1 to 11 The light guide structure 110 is similar to the light guide structure 110, except that the lens layer 118 is not present and a thin glass sheet 148 is provided below the reflective layer 112. The thin glass sheet 148 is used to allow the light guide structure 110 to be substantially flush or coplanar with the bottom surface of the optical fiber 106 of the optical fiber array unit 102, which facilitates alignment of the reflector 114 within the reflective layer 112 with the optical fiber 106 and attachment of the integrated optical fiber array unit structure 500 to the photonic package 620 (e.g., see Figure 26 ). For example, in some cases, the thickness T3 of the thin glass sheet 148 is in a range between about 30 μm and about 70 μm (e.g., about 50 μm), but other thicknesses may be used depending on the diameter of the optical fiber 106. In addition, the glass material of the thin glass sheet 148 allows light (e.g., UV light) to pass through to cure the optical glue 636 used to attach the optical fiber array unit structure 500 to the photonic package 620 during the UV curing process (e.g., see Figure 26 ).

[0131] Although not shown, in other embodiments, the reflective layer 112 of the light guide structure 110 ″ may further include embedded waveguides and beam splitters (eg, the waveguide 136 and beam splitter 138 described above) in addition to the embedded reflector 114 .

[0132] The L-shaped carrier 150 is used to mechanically support the light guide structure 110" and the optical fiber array unit 102, thereby improving the structural stability of the integrated optical fiber array unit structure 500. In some cases, the L-shaped carrier 150 placed above the light guide structure 110" and the optical fiber array unit 102 allows force to be applied from above during assembly of the integrated optical fiber array unit structure 500, thereby making the light guide structure 110" flush with the bottom surface of the optical fiber 106 of the optical fiber array unit 102. In addition, the vertically extending portion of the L-shaped carrier 150 covers the sidewalls of the light guide structure 110", so that the optical elements (e.g., the reflector 114) within the light guide structure 110" are well protected. In some embodiments, the L-shaped carrier 150 includes a material that is transparent to ultraviolet light (e.g., glass or sapphire) to allow UV light to pass through during the UV curing process of the optical adhesive 636. In some cases, the thickness T4 of the L-shaped carrier 150 is in a range between about 300 μm and about 500 μm, but other thicknesses may also be used.

[0133] Figures 22 to 25 shows the formation according to some embodiments Figure 21 A cross-sectional view of an intermediate step of the integrated optical fiber array unit structure 500. Figure 22 In the Figure 6 Then, a suitable removal process (eg, CMP process, grinding process, etching process or other suitable removal process) is used to remove the silicon substrate 101 below the reflective layer 112 (see Figure 6 ).

[0134] Next, in Figure 23 In the embodiment, the glass substrate 148' is bonded to the bottom side of the reflective layer 112 by, for example, a bonding layer (not separately shown). The bonding layer can be the same as or similar to the bonding layer 125 described above. The glass substrate 148' is then thinned to a thickness T3 (e.g., about 30 μm to about 70 μm, as described above) using a thinning process (e.g., a grinding process, an etching process, or other suitable process) to form the previously formed glass substrate 148'. Figure 21 As described above, providing the thin glass sheet 148 can compensate for the height difference between the reflective layer 112 and the bottom surface of the optical fiber 106 of the optical fiber array unit 102, thereby facilitating the alignment of the reflector 114 in the reflective layer 112 with the optical fiber 106 (see, for example, FIG. Figure 24 ) between them.

[0135] Continue to refer Figure 23, a segmentation process is then performed to separate the plurality of light guide structures 110" formed on the same silicon substrate 101 into a plurality of individual light guide structures 110" (for simplicity, only one light guide structure 110" is shown). The thin glass sheet 148 is also cut through during the segmentation process. In some embodiments, the segmentation process may include sawing the scribe line 154 using a mechanical saw. Other suitable segmentation processes may also be used. In some embodiments, after the segmentation process, the reflector 114 is embedded within the light guide structure 110" and is not exposed. In this way, the risk of damaging the passive optical elements (e.g., including the reflector 114) of the light guide structure 110" during subsequent assembly steps can be reduced. Although not shown, in other embodiments, various other passive optical elements (e.g., the waveguide 136 and / or the beam splitter 138 described above) may be integrated into the reflective layer 112 to improve optical performance, as described above.

[0136] Next, in Figure 24 In the embodiment, after forming the light guide structure 110", the optical adhesive 128 is used to connect the optical fiber array unit 102 and the light guide structure 110". The connection method between the optical fiber array unit 102 and the light guide structure 110" can be similar to Figure 10 The connection method between the optical fiber array unit 102 and the light guide structure 110 is shown, so similar details are not repeated here.

[0137] Next, in Figure 25 In the process, use optical adhesive 152 to Figure 24 The resulting structure is connected to the L-shaped carrier 150 to form the previously referenced Figure 21 The integrated fiber array unit (FAU) structure 500 is described. Similarly, the optical glue 152 can be dispensed in liquid form and subsequently cured (e.g., by UV curing). The optical glue 152 can extend between the top surface of the fiber array unit 102 and the light guide structure 110" and the horizontal extension of the L-shaped carrier 150, and can extend between the side walls of the light guide structure 110" and the vertical extension of the L-shaped carrier 150. The L-shaped carrier 150 enhances the structural stability of the integrated fiber array unit structure 500 and protects the optical components therein (e.g., the reflector 114).

[0138] It should be understood that the structures, configurations, and manufacturing methods described herein are illustrative only and are not intended to, and should not be construed to, limit the present invention. Numerous alternatives and modifications will be readily apparent to those skilled in the art upon learning the contents of the present invention. For example, the various features of the various embodiments described above may be combined in any manner.

[0139] Figure 26A cross-sectional view of a portion of a semiconductor package 600 (also referred to as a semiconductor system) according to some embodiments is shown. The semiconductor package 600 includes an integrated fiber array unit structure (e.g., Figure 12 Fiber array unit structure 200 is shown. In other embodiments, fiber array unit structure 200 may be replaced with fiber array unit structure 100, fiber array unit structure 300, fiber array unit structure 400, or fiber array unit structure 500. The assembly of fiber array unit structure 200 within semiconductor package 600 will be described later.

[0140] The semiconductor package 600 includes a packaging substrate 610, which is used to provide electrical connections between various semiconductor devices (e.g., the photonic package 620 described below and other devices not shown) packaged in the semiconductor package 600 and external electronic devices (not shown). In some embodiments, the packaging substrate 610 is a printed circuit board (PCB), which can be a cored or coreless substrate. The details of the printed circuit board are not described here. Other suitable packaging substrates may also be used. In some embodiments, various device elements (not shown), such as active or passive components (e.g., transistors, diodes, resistors, capacitors, inductors, etc.), may also be formed in or on the packaging substrate 610. Although not shown, an electrical connector may be formed on the bottom of the packaging substrate 610 to achieve electrical connection between the semiconductor package 600 and the external electronic device.

[0141] According to some embodiments, the photonic package 620 is attached (e.g., bonded) to the packaging substrate 610. The photonic package 620 includes an electronic die 621 bonded to a photonic die 622. For simplicity, details of the electronic die 621 and the photonic die 622 are not shown. The electronic die 621 can be, for example, a semiconductor device, a die, or a wafer that communicates with the photonic die 622 using electrical signals. The electronic die 621 does not receive, transmit, or process optical signals. In contrast, the photonic die 622 can receive, transmit, or process optical signals, for example, converting optical signals into electrical signals, or vice versa. In addition to optical signals, the photonic die 622 can also transmit, receive, or process electrical signals.

[0142] In some embodiments, the electronic die 621 includes a substrate (e.g., a semiconductor substrate such as silicon), electronic components (e.g., transistors, diodes, capacitors, resistors, etc.) formed in and / or on the substrate, and an interconnect structure formed on the substrate for interconnecting the electronic components to form an integrated circuit. The photonic die 622 may include a substrate (e.g., a buried oxide (BOX) substrate), photonic components (e.g., photodetectors, modulators, etc.) formed in and / or on the substrate, waveguides, optical couplers (e.g., grating couplers or edge couplers), and / or other photonic structures, and an interconnect structure formed on the substrate and electrically connected to the photonic components. The photonic components, waveguides, and optical couplers can be optically coupled to form a "photonic integrated circuit (PIC)" for receiving, transmitting, or processing optical signals. The interconnect structure of the electronic die 621 and the interconnect structure of the photonic die 622 can be electrically connected to each other.

[0143] In some embodiments, the integrated circuits of electronics die 621 include controllers, drivers, transimpedance amplifiers, or a combination thereof for controlling the operation of the photonic components of photonic die 622. In some embodiments, electronics die 621 provides serializer / deserializer (SerDes) functionality. In this way, electronics die 621 can serve as part of the I / O interface between optical and electrical signals within photonic package 620.

[0144] In some embodiments, the electronic die 621 can be bonded to the photonic die 622 via a suitable bonding process, such as dielectric-to-dielectric bonding and / or metal-to-metal bonding (e.g., direct bonding, fusion bonding, oxide-to-oxide bonding, hybrid bonding, etc.). Although not shown, a bonding layer can be provided at the interface between the electronic die 621 and the photonic die 622 to facilitate the bonding process. Further details regarding the photonic package 620 will not be repeated here.

[0145] In some embodiments, the photonic package 620 is bonded to contact pads (not shown) exposed on the upper surface of the packaging substrate 610 via electrical connectors 623. The electrical connectors 623 may include conductive posts, solder balls, controlled collapse chip connection (C4) bumps, microbumps, one or more other suitable bonding structures, or a combination thereof. An underfill layer 624 may be formed in the gap between the photonic package 620 and the packaging substrate 610 to surround and protect the electrical connectors 623 and enhance the connection between the photonic package 620 and the packaging substrate 610. In some embodiments, a metal cover 630 is attached to the top surface of the packaging substrate 610 via an adhesive 632, which helps reduce warping of the packaging substrate 610. The metal cover 630 may also be attached to the photonic package 620 via a thermal interface material (TIM) 634 to help dissipate heat. In some embodiments, the metal cover 630 further has an opening 631 (depicted in dashed lines) that allows the integrated fiber array unit structure 200 to be attached to the photonic package 620. In other embodiments, the metal cover 630 may be replaced by a reinforcement ring.

[0146] In some embodiments, the assembly of the integrated optical fiber array unit structure 200 and the photonic package 620 may include the following operations: placing the optical fiber array unit structure 200 on the exposed surface of the photonic package 620 through the opening 631 of the metal cover 630; aligning the reflector 114 (or the silicon lens 120, if present) of the optical fiber array unit structure 200 with the optical coupler (not shown) within the photonic package 620; dispensing optical glue 636 into the gap between the optical fiber array unit structure 200 and the photonic package 620; and then curing (e.g., UV curing) the optical glue 636.

[0147] Due to the above structural design of the integrated optical fiber array unit structure 200, the optical signal from the optical fiber 106 can be guided (e.g., redirected) by the reflector 114 in the reflective layer 112 to the lens layer 118 below, then pass through the silicon lens 120 and the carrier 130, and then enter the photonic package 620, and then reach the optical coupler (e.g., grating coupler or edge coupler, not released) in the photonic package 620, as shown in FIG. Figure 26 As shown in the optical path S in FIG. , optical coupling is achieved between the optical fiber 106 of the integrated optical fiber array unit structure 200 and the optical coupler in the photonic package 620. Although not shown, in some cases, one or more lenses and / or reflectors may be further provided in the photonic package 620 to facilitate such optical coupling.

[0148] Embodiments of the fiber array unit (FAU) structure discussed herein can offer several advantages. By integrating the fiber array unit (FAU) holding the optical fibers with a light guide structure (which may include various passive optical components, such as reflectors, lenses, waveguides, and / or beamsplitters), there's no need to add additional passive optical components outside of the FAU structure, thereby reducing the area occupied by these optical components within the semiconductor package. Consequently, the package size of the semiconductor package / system can be reduced. Because the passive optical components are embedded within the light guide structure and not exposed, the risk of damage to these components during assembly of the FAU structure with the photonic package is reduced. Consequently, the product yield and reliability of the integrated FAU structure are improved. In some embodiments, a carrier plate or L-shaped support is included to provide mechanical support for the FAU and light guide structure, thereby enhancing the structural stability of the integrated FAU structure. Furthermore, the bottom of the integrated FAU structure can include a UV-transparent material (e.g., glass or sapphire) to allow UV light to pass through, facilitating the UV curing process of the optical adhesive used to attach the FAU structure to the photonic package.

[0149] According to some embodiments, a fiber array unit (FAU) structure is provided. The fiber array unit structure includes a fiber array unit, a passive optical component structure, and a carrier board. The fiber array unit includes a fiber holder that holds a plurality of optical fibers. The passive optical component structure includes a reflective layer and a lens layer. The reflective layer includes a plurality of reflectors, wherein the reflectors are adjacent to the optical fibers. The lens layer includes a plurality of silicon lenses, wherein the silicon lenses are adjacent to the reflectors. The carrier board is configured to support the fiber array unit and the passive optical component structure. The fiber array unit and the passive optical component structure are adjacent to each other. The lens layer is located between the reflective layer and the carrier board.

[0150] In some embodiments, the optical fiber holder includes a plurality of grooves formed on the lower surface of the optical fiber holder to hold the optical fiber, wherein the optical fiber is located between the optical fiber holder and the carrier. In some embodiments, the reflective layer further includes a dielectric layer, and the reflector is embedded in the dielectric layer. In some embodiments, the reflective layer further includes a plurality of waveguides and a plurality of optical splitters embedded in the dielectric layer. In some embodiments, the lens layer is a silicon lens layer, and the lens layer further includes a plurality of silicon pillars and a gap filling material, the gap filling material filling the gaps between the silicon pillars and between the silicon pillars and the silicon lenses. In some embodiments, the passive optical element structure further includes a glass cover disposed on a side of the reflective layer opposite to the lens layer. In some embodiments, the passive optical element structure further includes a passivation layer disposed on a side of the reflective layer opposite to the lens layer. In some embodiments, the optical fiber array unit structure further includes a first optical adhesive and a second optical adhesive, wherein the first optical adhesive is disposed between the passive optical element structure and the adjacent sidewalls of the optical fiber array unit, and the second optical adhesive is disposed between the passive optical element structure and the bottom surface of the optical fiber array unit and the top surface of the carrier. In some embodiments, the passive optical component structure is bonded to the top surface of the carrier via a bonding layer, and the optical fiber array unit is attached to the top surface of the carrier via an optical adhesive, wherein the optical adhesive further extends into the gap between the passive optical component structure and the adjacent sidewalls of the optical fibers. In some embodiments, the carrier has a recess formed on the top surface of the carrier to accommodate the optical fibers.

[0151] According to some embodiments, a method for forming an optical fiber array unit structure is provided. The method includes forming a reflective layer on a silicon substrate, wherein the reflective layer includes a plurality of reflectors embedded in a dielectric layer. The method includes bonding a glass cover to a side of the reflective layer opposite to the silicon substrate. The method includes thinning the silicon substrate to form a thinned silicon substrate. The method includes etching the thinned silicon substrate to form a silicon lens layer, the silicon lens layer including a plurality of silicon lenses. The method includes performing a segmentation process to cut through the glass cover, the reflective layer, and the silicon lens layer to separate into a plurality of passive optical element structures. The method includes providing an optical fiber array unit. The method includes attaching the optical fiber array unit and the passive optical element structure to a carrier board, wherein the optical fiber array unit and the passive optical element structure are adjacent to each other

[0152] In some embodiments, the method further comprises connecting the optical fiber array unit and the passive optical element using a first optical glue before attaching the optical fiber array unit and the passive optical element to the carrier, and attaching the optical fiber array unit and the passive optical element to the carrier using a second optical glue. In some embodiments, the method further comprises performing an alignment process to align the reflector of the reflective layer of the passive optical element with the optical fiber of the optical fiber array unit before connecting the optical fiber array unit and the passive optical element using the first optical glue. In some embodiments, forming the silicon lens layer further comprises etching a thinned silicon substrate to form a plurality of silicon pillars, filling the gaps between the silicon pillars and between the silicon pillars and the silicon lenses with a gap filling material, and performing a flattening process to remove excess portions of the gap filling material along the bottom surfaces of the silicon pillars. In some embodiments, the carrier comprises a material transparent to ultraviolet light that allows ultraviolet light to pass therethrough.

[0153] According to some embodiments, a method for forming a fiber array unit structure is provided. The method includes forming a reflective layer on a silicon substrate, wherein the reflective layer includes a plurality of reflectors embedded in a dielectric layer. The method includes forming a protective material on a side of the reflective layer opposite the silicon substrate. The method includes bonding a glass cover to the protective material. The method includes thinning the silicon substrate to form a thinned silicon substrate. The method includes etching the thinned silicon substrate to form a silicon lens layer, the silicon lens layer including a plurality of silicon lenses. The method includes bonding a carrier to the side of the silicon lens layer opposite the reflective layer. The method includes removing the glass cover. The method includes removing the protective material, reflective layer, and silicon lens layer on the carrier in a fiber placement region of the carrier. The method includes cutting through the protective material, reflective layer, silicon lens layer, and carrier to separate the plurality of passive optical element structures, wherein each of the passive optical element structures is bonded to the carrier after the cutting is performed. The method includes providing a fiber array unit. The method includes attaching the fiber array unit to the fiber placement region of the carrier.

[0154] In some embodiments, the method further includes, before performing the cutting through, forming a recess on the top surface of the carrier by removing a portion of the fiber placement area of ​​the carrier, wherein the recess of the carrier is configured to accommodate the plurality of optical fibers of the fiber array unit. In some embodiments, the fiber array unit is attached to the fiber placement area of ​​the carrier using optical adhesive, wherein the optical adhesive further extends into the gap between the passive optical component structure and the adjacent sidewalls of the optical fibers. In some embodiments, the optical adhesive further extends onto the top surface of the protective material. In some embodiments, the reflective layer further includes a plurality of waveguides and a plurality of optical splitters embedded within the dielectric layer.

[0155] The above summarizes the features of many embodiments so that those skilled in the art to which the present invention belongs can better understand the various embodiments of the present invention. Those skilled in the art to which the present invention belongs should understand that other processes and structures can be easily designed or modified based on the embodiments of the present invention to achieve the same purposes and / or obtain the same advantages as the embodiments described herein. Those skilled in the art to which the present invention belongs should also understand that these equivalent structures do not depart from the spirit and scope of the present invention. Various changes, substitutions, and modifications may be made to the embodiments of the present invention without departing from the spirit and scope of the appended claims.

Claims

1. An optical fiber array unit structure, characterized in that: include: An optical fiber array unit including an optical fiber holder for holding a plurality of optical fibers; A passive optical component structure comprising: a reflective layer comprising a plurality of reflectors, wherein a plurality of the reflectors are adjacent to a plurality of the optical fibers; and a lens layer comprising a plurality of silicon lenses, wherein the plurality of silicon lenses are adjacent to the plurality of reflectors; and a carrier board configured to support the optical fiber array unit and the passive optical component structure, The optical fiber array unit and the passive optical element structure are adjacent to each other, and the lens layer is located between the reflective layer and the carrier board.

2. The optical fiber array unit structure according to claim 1, wherein: The optical fiber holder includes a plurality of grooves formed on a lower surface of the optical fiber holder for holding the plurality of optical fibers, wherein the plurality of optical fibers are located between the optical fiber holder and the carrier plate.

3. The optical fiber array unit structure according to claim 1, wherein: The reflective layer further includes a dielectric layer, and the plurality of reflectors are embedded in the dielectric layer.

4. The optical fiber array unit structure according to claim 3, wherein: The reflective layer also includes a plurality of waveguides and a plurality of optical splitters embedded within the dielectric layer.

5. The optical fiber array unit structure according to claim 1, wherein: The lens layer is a silicon lens layer, and the lens layer further includes a plurality of silicon pillars and a gap filling material. The gap filling material fills the gaps between the silicon pillars and between the silicon pillars and the silicon lenses.

6. The optical fiber array unit structure according to claim 1, wherein: The passive optical element structure further includes a glass cover disposed on a side of the reflective layer opposite to the lens layer.

7. The optical fiber array unit structure according to claim 1, wherein: The passive optical element structure further includes a passivation layer disposed on a side of the reflective layer opposite to the lens layer.

8. The optical fiber array unit structure according to claim 1, wherein: Also includes: a first optical adhesive disposed between the passive optical element structure and an adjacent side wall of the optical fiber array unit; as well as A second optical adhesive is disposed between the passive optical element structure, the bottom surface of the optical fiber array unit, and the top surface of the carrier board.

9. The optical fiber array unit structure according to claim 1, wherein: The passive optical element structure is bonded to a top surface of the carrier through a bonding layer, and the optical fiber array unit is attached to the top surface of the carrier through an optical glue, wherein the optical glue further extends into the gap between the passive optical element structure and adjacent side walls of the plurality of optical fibers.

10. The optical fiber array unit structure according to claim 9, wherein: The carrier has a recess formed on the top surface of the carrier to accommodate the plurality of optical fibers.

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