A silicon optical packaging device and a method of manufacturing the same

Abstract

The application provides a silicon optical packaging device and a preparation method thereof. The silicon optical packaging device comprises a light guide structure, a heat dissipation structure, a plastic sealing layer, a first structure and a second structure. The light guide structure is a right trapezoidal structure. A surface where a non-right waist of the light guide structure is located is a total reflection surface. Light signals entering the light guide structure from a direction parallel to a bottom side of the surface where the right waist is located can be totally reflected to a plane where a front surface of the plastic sealing layer is located. The heat dissipation structure is arranged in a spaced manner with the light guide structure and is embedded in the plastic sealing layer. The light guide structure can greatly reduce transmission loss of the light guide structure in transmitting light signals. The light guide structure and the heat dissipation structure are embedded in the plastic sealing layer, so that the heat dissipation capacity can be improved. The first structure and the second structure are directly formed on two sides of the plastic sealing layer, so that the silicon optical packaging device can replace a PCB substrate and an optical path, and the space utilization rate is improved.

Description

Technical Field

[0001] This invention relates to the field of optical technology, and in particular to a silicon photonics packaging device and its fabrication method. Background Technology

[0002] Silicon optical modules employ two light transmission methods. The first method involves forming a linear optical path made of polymer material on a PCB substrate. This path has an input and an output end. The input end connects to an optical fiber, and the output end connects to an optical chip. Because this optical path is located below the connection end of the optical chip, the output end needs to extend the optical path towards the connection end of the optical chip, resulting in a right-angle extension at its end. Since the optical signal enters at the input end and undergoes diffuse reflection at the end, a small amount of the signal passes through the extension and enters the optical chip, leading to significant signal loss (approximately only 10%–20% of the original signal remains). The second method involves forming a thin layer of silicon dioxide on a silicon substrate as a light guide structure. This light guide structure has a shape roughly the same as the optical path and has two ends, one of which connects to an optical fiber. Because the thickness of the silicon dioxide layer is less than the thickness of the optical path, the signal loss in this light guide structure is even more severe. In addition, since silicon dioxide cannot directly process optical signals transmitted through optical fibers, the optical signals need to be converted into signals that the optical chip can receive. Therefore, the other end of the optical guide structure cannot be directly connected to the optical chip. Summary of the Invention

[0003] The purpose of this invention is to provide a silicon photonics packaging device and its fabrication method, which can reduce the loss of optical signals before entering the optical chip.

[0004] To address the aforementioned problems, this invention provides a silicon photonics packaging device, comprising a light guide structure, a heat dissipation structure, a molding layer, a first structure, a second structure, and an optical chip.

[0005] The optical guide structure is a right-angled trapezoidal structure with a front and a back side arranged opposite to each other. Its longitudinal section includes a first bottom edge and a second bottom edge arranged opposite to each other, and a first side edge and a second side edge arranged opposite to each other. The first bottom edge is located on the front side of the optical guide structure, and the second bottom edge is located on the back side of the optical guide structure. The length of the first bottom edge is greater than the length of the second bottom edge, and the angle between the first bottom edge and the first side edge is 90°. The angle between the first bottom edge and the second side edge is around 45°. The optical guide structure is connected to an optical fiber in the plane where the first side edge is located. The surface where the second side edge is located is a total reflection surface, which can totally reflect the optical signal entering the optical guide structure from the surface where the first side edge is located in a direction parallel to the front side to the plane where the first bottom edge is located.

[0006] The heat dissipation structure is spaced apart from the light guide structure and embedded in the molding layer. The heat dissipation structure has a front and a back that are arranged opposite to each other, and the second side is located between the heat dissipation structure and the first side.

[0007] The molding compound has a front and a back side disposed opposite to each other, and a first side side and a second side side disposed opposite to each other. The light guide structure, the heat dissipation structure and the front side of the molding compound are disposed on the same side. The first side side of the molding compound is disposed parallel to the plane containing the first side edge, and the first side edge is located between the first side side and the second side side. The front side of the molding compound exposes the front side of the light guide structure and the front side of the heat dissipation structure. The back side of the molding compound exposes the back side of the heat dissipation structure. The back side of the light guide structure is located between the front side and the back side of the molding compound. The molding compound has a plurality of through holes that penetrate the molding compound along the thickness direction and are filled with conductive material.

[0008] The first structure is located on the front side of the molding compound, and the first structure is electrically connected from the front side of the molding compound to the conductive material in the through hole and the heat dissipation structure;

[0009] The second structure is located on the back side of the molding compound, and the second structure is electrically connected from the back side of the molding compound to the conductive material in the through-hole and the heat dissipation structure; and

[0010] The optical chip is located on the first structure and is electrically connected to the first structure, and is also connected to the front light of the light guide structure.

[0011] Optionally, the included angle between the first bottom edge and the second side edge is 45°.

[0012] Optionally, the light guide structure includes a light conductor and a low-reflectivity coating applied to the surface of the light conductor. The light conductor is made of glass, and the reflectivity of the low-reflectivity coating is lower than that of the light conductor, such that a light signal entering the light guide structure from the surface of the first side parallel to the front of the light guide structure is totally reflected by the plane of the second side to the plane of the first bottom side.

[0013] Furthermore, the light guide structure has a connection port on the plane of the first side, the connection port is used to connect an optical fiber, and the low reflectivity coating at the connection port exposes the light conductor.

[0014] Furthermore, a guide groove is provided on the front side of the molding layer, the guide groove passing through the molding layer between the first side and the connection port, and the optical fiber is placed in the guide groove.

[0015] Furthermore, the guide groove is a V-shaped groove.

[0016] Furthermore, the front side of the light guide structure has a light outlet, and the low reflectivity coating at the light outlet exposes the light conductor. The light outlet is used to connect to the optical chip, and after total internal reflection of the light signal entering the light guide structure from the connection port in a direction parallel to the front side of the light guide structure, it is transmitted to the optical chip in a direction perpendicular to the front side of the light guide structure through the light outlet.

[0017] Furthermore, the shape of the light outlet is circular or square.

[0018] Furthermore, the optical chip has an optical connection port and an electrical connection port, the optical connection port being optically connected to the light output port, and the electrical connection port being electrically connected to the first structure.

[0019] Optionally, the thickness of the optical guide structure is 100 micrometers to 150 micrometers.

[0020] Optionally, the first structure includes a first passivation layer, a first metal layer, and a second passivation layer sequentially formed on the front side of the molding compound.

[0021] The first passivation layer covers the front side of the molding compound, the front side of the heat dissipation structure, and the front side of the light guide structure, and exposes the conductive material in the through hole, a part of the front area of ​​the heat dissipation structure, the light outlet of the light guide structure, and the guide groove on the front side of the molding compound from the front side of the molding compound.

[0022] The first metal layer is located on a portion of the first passivation layer. The first metal layer includes a plurality of first solder pads, which are electrically connected to the conductive material and the heat dissipation structure in the via, respectively.

[0023] The second passivation layer covers the first passivation layer and the first metal layer. At least two first connection holes are formed in the second passivation layer. The first connection holes expose the first metal layer and are filled with conductive material for electrically connecting the optical chip.

[0024] Optionally, it includes a third passivation layer, a second metal layer, and a fourth passivation layer sequentially formed on the back side of the molding compound.

[0025] The third passivation layer covers the back side of the molding compound and the back side of the heat dissipation structure, and exposes the conductive material in the via and a portion of the back side of the heat dissipation structure from the back side of the molding compound;

[0026] The second metal layer includes a plurality of second solder pads located on a portion of the third passivation layer and electrically connected to the conductive material in the via and the heat dissipation structure, respectively; and

[0027] The fourth passivation layer covers the third passivation layer and the second metal layer. The fourth passivation layer has at least two second connection holes, which expose the second metal layer. The second connection holes are filled with conductive material, which is used for electrical connection to external circuits.

[0028] On the other hand, the present invention also provides a method for fabricating a silicon photonics packaging device, which includes the following steps:

[0029] A light guide structure and a heat dissipation structure to be packaged are provided. The light guide structure is a right-angled trapezoidal structure with a front and a back side arranged opposite to each other. Its longitudinal section includes a first bottom edge and a second bottom edge arranged opposite to each other, and a first side edge and a second side edge arranged opposite to each other. The first bottom edge is located on the front side of the light guide structure, and the second bottom edge is located on the back side of the light guide structure. The length of the first bottom edge is greater than the length of the second bottom edge, and the angle between the first bottom edge and the first side edge is 90°. The angle between the first bottom edge and the second side edge is around 45°. An optical fiber is connected to the plane where the first side edge is located. The surface where the second side edge is located is a total internal reflection surface, which can totally reflect the light signal entering the light guide structure from the surface where the first side edge is located in a direction parallel to the front side to the plane where the first bottom edge is located. The heat dissipation structure has a front and a back side arranged opposite to each other, and the second side edge is located between the heat dissipation structure and the first side edge.

[0030] A first carrier plate is provided, and a first adhesive layer is formed on one side of the first carrier plate. The light guide structure and the heat dissipation structure are placed on the first adhesive layer at intervals, wherein the front sides of the heat dissipation structure and the light guide structure both face the first adhesive layer.

[0031] A molding compound is filled between the light guide structure and the heat dissipation structure, and the molding compound is cured to form a molding layer. The molding layer has a front and a back side disposed opposite to each other, as well as a first side side and a second side side disposed opposite to each other. The light guide structure, the heat dissipation structure, and the front side of the molding layer are disposed on the same side. The first side side of the molding layer is disposed parallel to the plane containing the first side side, and the first side side is located between the first side side and the second side side. The front side of the molding layer exposes the front side of the light guide structure and the front side of the heat dissipation structure. The back side of the molding layer exposes the back side of the heat dissipation structure. The back side of the light guide structure is located between the front side and the back side of the molding layer.

[0032] Remove the first carrier board;

[0033] A plurality of through-holes are formed in the molding compound, the through-holes penetrating the molding compound along its thickness direction, and the through-holes are filled with conductive material; a first structure is formed on the front side of the molding compound, the first structure being electrically connected from the front side of the molding compound to the conductive material in the through-holes and the heat dissipation structure; a second structure is formed on the back side of the molding compound, the second structure being electrically connected from the back side of the molding compound to the conductive material in the through-holes and the heat dissipation structure; and

[0034] An optical chip is provided, which is fixed on the first structure and electrically connected to the first structure, and is also connected to the front light of the light guide structure.

[0035] Optionally, a guide groove is also formed in the molding compound, the guide groove being located on the front side of the molding compound and penetrating the molding compound between the first side and the connection port, thus exposing the connection port.

[0036] Optionally, the optical chip has an optical connection port and an electrical connection port. The optical connection port is optically connected to the light output port of the light guide structure, and the electrical connection port is electrically connected to the first structure.

[0037] Compared with the prior art, the present invention has the following beneficial effects:

[0038] This invention provides a silicon photonics packaging device and its fabrication method. The silicon photonics packaging device includes a light guide structure, a heat dissipation structure, a molding compound, a first structure, a second structure, and an optical chip. The light guide structure is a right-angled trapezoidal structure with a front and a back side arranged opposite each other. Its longitudinal section includes a first bottom edge and a second bottom edge arranged opposite each other, as well as a first side edge and a second side edge arranged opposite each other. The first bottom edge is located on the front side of the light guide structure, and the second bottom edge is located on the back side of the light guide structure. The length of the first bottom edge is greater than the length of the second bottom edge, and the angle between the first bottom edge and the first side edge is 90°. The angle between the first bottom edge and the second side edge is approximately 45°. An optical fiber is connected to the plane containing the first side edge of the light guide structure. The heat dissipation structure is spaced apart from the light guide structure and embedded in the molding compound. The heat dissipation structure has a front and a back side arranged opposite each other, and the second side edge is located between the heat dissipation structure and the first side edge. The molding compound has a front and a back side arranged opposite each other, as well as a first side edge and a second side edge arranged opposite each other. The light guide structure... The heat dissipation structure and the front side of the molding compound are disposed on the same side. The first side of the molding compound is parallel to the plane containing the first side edge, and the first side edge is located between the first side edge and the second side edge. The front side of the molding compound exposes the front side of the light guide structure and the front side of the heat dissipation structure. The back side of the molding compound exposes the back side of the heat dissipation structure. The back side of the light guide structure is located between the front side and the back side of the molding compound. The molding compound has multiple through holes that penetrate the molding compound along the thickness direction and are filled with conductive material. The first structure is located on the front side of the molding compound and is electrically connected from the front side of the molding compound to the conductive material in the through holes and the heat dissipation structure. The second structure is located on the back side of the molding compound and is electrically connected from the back side of the molding compound to the conductive material in the through holes and the heat dissipation structure. The optical chip is located on the first structure and is electrically connected to the first structure and is also optically connected to the front side of the light guide structure. The optical guide structure of the present invention has virtually no optical signal loss during the entire process of transmitting optical signals, greatly reducing the transmission loss of optical signals transmitted by the optical guide structure; furthermore, by embedding the optical guide structure and heat dissipation structure in the molding compound, the heat dissipation capacity can be improved. The first structure and the second structure are directly formed on both sides of the molding compound, so that the silicon photonics packaging device of this embodiment replaces the PCB substrate and the optical path, improving space utilization, reducing the size of the silicon photonics packaging device, and thus saving space. Attached Figure Description

[0039] Figure 1 This is a schematic diagram of a silicon photonics packaging device according to an embodiment of the present invention;

[0040] Figure 2This is a schematic diagram of the guide groove provided in an embodiment of the present invention;

[0041] Figure 3 This is a schematic diagram of an optical guide structure provided in an embodiment of the present invention.

[0042] Explanation of reference numerals in the attached figures:

[0043] 1-Fiber optic cable; 110-Optical guide structure; 111-Optical conductor; 111a-First bottom edge; 111b-Second bottom edge; 111c-First side edge; 111d-Second side edge; 112-Low reflectivity coating; 120-Heat dissipation structure; 130-Encapsulation layer; 140-Through hole; 150-Guide groove; 210-First passivation layer; 211-Light outlet; 220-First metal layer; 230-Second passivation layer; 240-First connection hole; 310-Third passivation layer; 320-Second metal layer; 330-Fourth passivation layer; 340-Second connection hole. Detailed Implementation

[0044] The following will provide a more detailed description of a silicon photonics packaging device and its fabrication method according to the present invention. The invention will now be described in more detail with reference to the accompanying drawings, which illustrate preferred embodiments of the invention. It should be understood that those skilled in the art can modify the invention described herein while still achieving its advantageous effects. Therefore, the following description should be understood as being of general knowledge to those skilled in the art and is not intended to limit the invention.

[0045] For clarity, not all features of the actual embodiments are described. In the following description, well-known functions and structures are not detailed in detail, as they would obscure the invention with unnecessary detail. It should be understood that in the development of any actual embodiment, numerous implementation details must be made to achieve the developer's specific objectives, such as changes from one embodiment to another according to limitations related to the system or business. Furthermore, it should be understood that such development work may be complex and time-consuming, but is merely routine work for those skilled in the art.

[0046] To make the objectives and features of the present invention more apparent and understandable, the specific embodiments of the present invention will be further described below with reference to the accompanying drawings. It should be noted that the drawings are all in a very simplified form and use non-precise ratios, and are only used to conveniently and clearly assist in illustrating the objectives of the embodiments of the present invention.

[0047] Figure 1 This is a schematic diagram of a silicon photonics packaging device provided in this embodiment. Figure 1As shown, this embodiment provides a silicon photonics packaging device, including a light guide structure 110, a heat dissipation structure 120, and a molding compound 130. The light guide structure 110 and the heat dissipation structure 120 are spaced apart and embedded in the molding compound 130. The molding compound 130 has a front and a back side disposed opposite to each other, and a first side and a second side side disposed opposite to each other. The first side and the second side side connect the front side and the back side of the molding compound 130. Both the light guide structure 110 and the heat dissipation structure 120 have front and back sides disposed opposite to each other, and the front sides of the molding compound 130, the light guide structure 110, and the heat dissipation structure 120 are disposed on the same side. The front side of the molding compound 130 exposes the front side of the light guide structure 110 and the front side of the heat dissipation structure 120, and the back side of the molding compound 130 exposes the back side of the heat dissipation structure 120. The thickness of the molding layer 130 is the same as the thickness of the heat dissipation structure 120, and the thickness of the heat dissipation structure 120 is greater than the thickness of the light guide structure 110, so that the back side of the molding layer 130 does not expose the back side of the light guide structure 110, that is, the back side of the light guide structure 110 is located between the front and back sides of the molding layer 130.

[0048] Figure 3 This is a schematic diagram of the optical guide structure provided in this embodiment. Figure 3 As shown, the light guide structure 110 is a right-angled trapezoidal structure, and its cross-section (i.e., longitudinal section) in the thickness direction is also a right-angled trapezoidal, so that the light guide structure 110 has a first bottom edge 111a and a second bottom edge 111b arranged opposite to each other, and a first side edge 111c and a second side edge 111d arranged opposite to each other. The first bottom edge 111a is located on the front side of the light guide structure, and the second bottom edge 111b is located on the back side of the light guide structure 110. The first side of the molding layer is parallel to the plane where the first side edge 111c is located, and the first side edge 111c is located between the first side edge and the second side edge 111d. The first side edge 111c is located closer to the first side edge, and the second side edge 111d is located closer to the second side edge, so that the second side edge 111d is located between the heat dissipation structure and the first side edge 111c. The length of the first bottom edge 111a is greater than the length of the second bottom edge 111b, and the angle between the first bottom edge 111a and the first side edge 111c is 90°. The angle between the first bottom edge 111a and the second side edge 111d is around 45°. Further, the angle between the first bottom edge 111a and the second side edge 111d is 40° to 50°. Preferably, the angle between the first bottom edge 111a and the second side edge 111d is 45°.

[0049] The optical guide structure 110 connects an optical fiber to the plane containing the first side 111c, and the surface containing the second side 111d is a total internal reflection surface, enabling optical signals entering the optical guide structure 110 from the surface containing the first side 111c in a direction parallel to the front of the molding layer to be completely reflected to the plane containing the first bottom edge. Specifically, the optical guide structure 110 includes an optical conductor 111 and a low-reflectivity coating 112 applied to the surface of the optical conductor 111. The optical conductor 111 is made of glass, and the reflectivity of the low-reflectivity coating 112 is lower than that of the optical conductor 111, allowing optical signals entering the optical guide structure 110 from the surface containing the first side 111c in a direction parallel to the front of the optical guide structure 110 to be completely reflected to the plane containing the first bottom edge 111a via the plane containing the second side 111d. The thickness of the optical guide structure 110 is 100 micrometers to 150 micrometers. It is currently difficult to fabricate an optical path using two reflective materials on a PCB substrate. In the semiconductor industry, only silicon dioxide and silicon nitride are suitable materials for optical signal transmission. These two materials have similar reflectivity, making total internal reflection of the optical signal impossible. Therefore, the optical guide structure 110 of this embodiment achieves total internal reflection of the optical signal entering the optical guide structure 110 through a high-reflectivity optical conductor 111 and a low-reflectivity coating 112. Furthermore, during optical signal propagation, the optical guide structure 110 of this embodiment can directly process the optical signal transmitted through the optical fiber without requiring further processing.

[0050] The surface of the optical guide structure 110 near the first side is provided with a connection port (not shown in the figure) for connecting the optical fiber 1, and the low reflectivity coating 112 at the connection port exposes the optical conductor 111, so that the optical signal in the optical fiber 1 can directly enter the optical conductor 111 at the connection port.

[0051] The light guide structure 110 has a light exit port 211 on its front side. The low-reflectivity coating at the light exit port 211 exposes the light conductor. The light exit port 211 is used to connect to the optical chip. Light signals entering the light guide structure 110 from the connection port in a direction parallel to the front side of the light guide structure 110 undergo total internal reflection in the plane of the second side 111d, and are then transmitted out through the light exit port in a direction perpendicular to the front side of the light guide structure 110. There is virtually no loss of light signal during the entire process. The shape of the light exit port 211 is a regular shape, such as a circle or a square. When the light exit port 211 is circular, its diameter is 50 micrometers to 100 micrometers. When the light exit port 211 is square, the length of each of its four sides is 50 micrometers to 100 micrometers.

[0052] The molding compound 130 is made of materials including epoxy resin, containing 85%-90% silica particles, and polymer materials. Currently, PCB substrates dissipate heat through surface copper, but the coefficient of thermal expansion of copper is greater than that of the PCB substrate itself, making it impossible to balance the thermal expansion coefficient of the PCB substrate. In this embodiment, the heat dissipation structure 120 can be made of metals (e.g., aluminum nitride composite metal), ceramics, etc., so that the thermal expansion coefficient of the heat dissipation structure is less than that of the molding compound, thereby obtaining a silicon photonics packaging device with a low thermal expansion coefficient, thus balancing the thermal expansion coefficients of heat dissipation and the silicon photonics packaging device.

[0053] A through-hole 140 is formed in the molding compound 130, extending through both the front and back sides of the molding compound 130 along its thickness direction. The through-hole 140 is filled with a conductive material. The conductive material filling the through-hole 140 is used to electrically connect the circuitry on the front side of the molding compound 130 to the circuitry on the back side of the molding compound 130. The conductive material may be, for example, a conductive metal, conductive alloy, or conductive adhesive such as Cu (copper), W (tungsten), Ag (silver), or Au (gold).

[0054] Figure 2 This is a schematic diagram of the guide groove provided in this embodiment. Figure 2 As shown, a guide groove 150 is also formed on the front side of the molding compound 130. The guide groove 150 extends through the molding compound 130 between the first side 111c and the connection port in a direction from the first side 111c to the second side 111d, and exposes the optical guide structure 110 facing the connection port. The guide groove 150 is used to place and connect the optical fiber 1. The guide groove 150 can be a V-groove so that the optical fiber 1 placed therein can stop automatically, thereby allowing the optical signal to enter the optical guide structure 110 in a direction parallel to the front side, and this structure is easy to implement. Preferably, the inner wall of the guide groove 150 is plated with a metal plating layer, such as a nickel-gold plating layer.

[0055] Please continue reading. Figure 1 The molding compound 130 has a first structure formed on its front side, and the first structure is electrically connected from the front side of the molding compound 130 to the conductive material in the through hole 140 and the heat dissipation structure 120.

[0056] The first structure includes a first passivation layer 210, a first metal layer 220, and a second passivation layer 230 sequentially formed on the front side of the molding compound 130. The first passivation layer 210 covers the front side of the molding compound 130 and the front side of the heat dissipation structure 120. To save space, the first passivation layer 210 also covers the front side of the light guide structure 110 to form a first metal layer on the front side of the light guide structure 110, thereby improving the utilization rate of the front side of the molding compound 130. The first passivation layer 210 exposes the conductive material in the via 140, a portion of the front area of ​​the heat dissipation structure 120, the light outlet 211, and the guide groove 150 from the front side of the molding compound 130.

[0057] The first metal layer 220 is located on a portion of the first passivation layer 210. The first metal layer 220 includes a plurality of first pads and internal circuitry. The plurality of first pads of the first metal layer 220 are electrically connected to the conductive material in the via 140 and the heat dissipation structure 120, respectively.

[0058] The second passivation layer 230 covers the first passivation layer 210 and the first metal layer 220. The first passivation layer 210 and the second passivation layer 230 are used to electrically isolate the first metal layer 220 to avoid short circuits. The second passivation layer 230 exposes the heat dissipation structure 120, the light outlet 211, the guide groove 150 and part of the first metal layer 220.

[0059] At least two first connection holes 240 are formed in the second passivation layer 230. The first connection holes 240 expose the first metal layer 220. The first connection holes 240 are filled with conductive material and are used for electrical connection to devices located above them, such as optical chips.

[0060] Both the first passivation layer 210 and the second passivation layer 230 are insulating materials, such as polymer materials, and more specifically, one or a combination of polyimide, benzocyclobutene (BCB), or poly(p-dioxazolebenzene) (PBO). The materials of the first passivation layer 210 and the second passivation layer 230 can be the same or different. In this embodiment, the materials of the first passivation layer 210 and the second passivation layer 230 are the same, for example, both are polyimide.

[0061] The first metal layer 220 can be a metallic material such as Cu, Ag, W or Au, a conductive alloy, a conductive oxide (e.g., ITO), or an inorganic material, or it can be a conductive organic material, such as a conductive polymer. The thickness of the first metal layer 220 on the surface of the first passivation layer 210 is about 3 micrometers to 10 micrometers, preferably 3 micrometers to 5 micrometers.

[0062] A second structure is formed on the back side of the molding compound 130. The second structure is electrically connected from the back side of the molding compound 130 to the conductive material in the via 140 and the heat dissipation structure 120. The second structure includes a third passivation layer 310, a second metal layer 320, and a fourth passivation layer 330 sequentially formed on the back side of the molding compound 130. The third passivation layer 310 covers the back side of the molding compound 130 and the back side of the heat dissipation structure 120, and exposes the conductive material in the via 140, a portion of the back side of the heat dissipation structure 120, and a portion of the back side of the molding compound 130 from the back side of the molding compound 130.

[0063] The second metal layer 320 includes a plurality of second solder pads located on a portion of the third passivation layer 310 and electrically connected to the conductive material in the via 140 and the heat dissipation structure 120, respectively.

[0064] The fourth passivation layer 330 covers the third passivation layer 310 and the second metal layer 320. The third passivation layer 310 and the fourth passivation layer 330 are used to electrically isolate the second metal layer 320 to prevent it from short-circuiting.

[0065] The fourth passivation layer 330 is provided with at least two second connection holes 340, the at least two second connection holes 340 expose the second metal layer 320, the second connection holes 340 are filled with conductive material, and the conductive material in the second connection holes 340 is used for electrical connection to external circuits (such as PCB substrate or FPC substrate).

[0066] Both the third passivation layer 310 and the fourth passivation layer 330 are insulating materials, such as polymer materials, and more specifically, one or a combination of polyimides, benzocyclobutene (BCB), or poly(p-dioxazolebenzene) (PBO). The materials of the first passivation layer 210, the second passivation layer 230, the third passivation layer 310, and the fourth passivation layer 330 can be completely identical, partially identical, or completely different. In this embodiment, the third passivation layer 310 and the fourth passivation layer 330 are made of the same material, for example, both are polyimides.

[0067] The second metal layer 320 can be a metallic material such as Cu, Ag, W or Au, a conductive alloy, a conductive oxide (e.g., ITO), or an inorganic material, or it can be a conductive organic material, such as a conductive polymer. The thickness of the second metal layer 320 on the surface of the third passivation layer 310 is about 3 micrometers to 10 micrometers, preferably 3 micrometers to 5 micrometers.

[0068] The silicon photonics packaging device further includes an optical chip (not shown in the figure), which is located on the first structure and electrically connected to the first structure, and also optically connected to the front side of the light guide structure. Specifically, the optical chip has an optical connection port and an electrical connection port; the optical connection port is optically connected to the light outlet 211, and the electrical connection port is electrically connected to the first structure.

[0069] In this embodiment, the light guide structure 110 and the heat dissipation structure 120 are embedded in the molding compound layer 130, which improves heat dissipation capacity. The first and second structures are directly formed on both sides of the molding compound layer 130, allowing the silicon photonics packaging device of this embodiment to replace the PCB substrate and optical path, improving space utilization, reducing the size of the silicon photonics packaging device, and thus saving space. At the same time, the structure of the light guide structure 110 in this embodiment greatly reduces the transmission loss of the optical signal transmitted by the light guide structure 110.

[0070] Please continue reading. Figure 1 This embodiment also provides a method for fabricating a silicon photonics packaging device, including the following steps:

[0071] S1: Provide a light guide structure 110 and a heat dissipation structure 120 to be packaged. The light guide structure 110 is a right trapezoidal structure with a front side and a back side arranged opposite to each other. Its longitudinal section includes a first bottom edge 111a and a second bottom edge 111b arranged opposite to each other, and a first side edge 111c and a second side edge 111d arranged opposite to each other. The first bottom edge is located on the front side of the light guide structure, and the second bottom edge is located on the back side of the light guide structure. Wherein, the length of the first bottom edge 111a is greater than the length of the second bottom edge 111b, and the angle between the first bottom edge 111a and the first side edge 111c is 90°, and the angle between the first bottom edge 111a and the second side edge 111d is around 45°. The optical fiber is connected to the plane where the first side edge 111c is located. The surface where the second side edge 111d is located is a total reflection surface, which can totally reflect the light signal entering the optical fiber from the surface where the first side edge 111c is located in a direction parallel to the front side to the plane where the first bottom edge 111a is located. The heat dissipation structure has a front side and a back side that are arranged opposite to each other, and the second side edge is located between the heat dissipation structure and the first side edge.

[0072] In this step, the light guide structure 110 includes a light conductor 111 and a low reflectivity coating 112 applied to the surface of the light conductor 111. The reflectivity of the low reflectivity coating 112 is lower than that of the light conductor 111. The light guide structure 110 is provided with a light outlet 211 on the front and a connection port on the plane of the first side 111c. The light outlet 211 and the connection port expose the light conductor 111.

[0073] S2: A first carrier plate is provided, on one side of which a first adhesive layer is formed. The light guide structure 110 and the heat dissipation structure 120 are placed at intervals on the first adhesive layer, wherein the front sides of the heat dissipation structure 120 and the light guide structure 110 both face the first adhesive layer, and the shape of the first carrier plate is, for example, square or circular.

[0074] S3: Fill the space between the light guide structure 110 and the heat dissipation structure 120 with molding material and cure the molding material to form a molding layer 130. The molding layer 130 has a front and a back side disposed opposite to each other, as well as a first side side and a second side side disposed opposite to each other. The front sides of the molding layer 130, the light guide structure 110 and the heat dissipation structure 120 are disposed on the same side. The first side side of the molding layer 130 is parallel to the plane where the first side edge 111c is located, and the first side edge 111c is located between the first side side and the second side edge 111d. The front side of the molding layer 130 exposes the front side of the heat dissipation structure 120 and the front side of the light guide structure 110. The back side of the molding layer 130 exposes the back side of the heat dissipation structure 120. The back side of the light guide structure 110 is located between the front side and the back side of the molding layer 130.

[0075] S4: Remove the first carrier board.

[0076] S5: A plurality of through holes 140 are formed in the molding compound 130, the through holes 140 penetrating the molding compound 130 along the thickness direction of the molding compound 130, and the through holes 140 are filled with conductive material; a first structure is formed on the front side of the molding compound 130, the first structure being electrically connected from the front side of the molding compound 130 to the conductive material in the through holes 140 and the heat dissipation structure 120; a second structure is formed on the back side of the molding compound 130, the second structure being electrically connected from the back side of the molding compound 130 to the conductive material in the through holes 140 and the heat dissipation structure 120.

[0077] In this step, a guide groove 150 is also formed in the molding compound 130. The guide groove 150 is located on the front side of the molding compound 130 and penetrates the side side (i.e. the first side side) of the molding compound 130 near the first side 111c, and exposes the connection port.

[0078] The guide groove 150 is obtained through laser manufacturing process. The first passivation layer 210 of the first structure exposes the light outlet 211, the conductive material in the through-hole 140, and part of the front side of the heat dissipation structure 120 through an opening process. The second passivation layer 230 of the first structure forms at least two first connection holes 240 through an opening process, exposing the first metal layer 220. The device is soldered by plating a nickel-gold plating layer or solder material at the at least two first connection holes 240. The third passivation layer 310 of the second structure exposes the conductive material in the through-hole 140 and part of the back side of the heat dissipation structure 120 through an opening process. The fourth passivation layer 330 of the second structure forms at least two second connection holes 340 through an opening process, exposing the second metal layer 320. The device is soldered to an external circuit by plating a nickel-gold plating layer or solder material at the at least two second connection holes 340.

[0079] S7: Provide an optical chip, fix the optical chip on the first structure, and electrically connect it to the first structure, and also connect it to the front side of the light guide structure. Specifically, the optical chip has an optical connection port and an electrical connection port. The optical connection port is optically connected to the light outlet 211, and the electrical connection port is electrically connected to the conductive material in a portion of the first connection hole 240. The electrical connection port is soldered to the first structure.

[0080] In summary, this invention provides a silicon photonics packaging device and its fabrication method. The silicon photonics packaging device includes a light guide structure, a heat dissipation structure, a molding compound, a first structure, a second structure, and an optical chip. The light guide structure is a right-angled trapezoidal structure with a front and a back side arranged opposite each other. Its longitudinal section includes a first bottom edge and a second bottom edge arranged opposite each other, as well as a first side edge and a second side edge arranged opposite each other. The first bottom edge is located on the front side of the light guide structure, and the second bottom edge is located on the back side of the light guide structure. The length of the first bottom edge is greater than the length of the second bottom edge, and the angle between the first bottom edge and the first side edge is 90°. The angle between the first bottom edge and the second side edge is approximately 45°. An optical fiber is connected to the plane containing the first side edge of the light guide structure. The heat dissipation structure is spaced apart from the light guide structure and embedded in the molding compound. The heat dissipation structure has a front and a back side arranged opposite each other, and the second side edge is located between the heat dissipation structure and the first side edge. The molding compound has a front and a back side arranged opposite each other, as well as a first side edge and a second side edge arranged opposite each other. The light guide structure... The structure, heat dissipation structure, and the front side of the molding compound are arranged on the same side. The first side of the molding compound is parallel to the plane containing the first side edge, and the first side edge is located between the first side edge and the second side edge. The front side of the molding compound exposes the front side of the light guide structure and the front side of the heat dissipation structure. The back side of the molding compound exposes the back side of the heat dissipation structure. The back side of the light guide structure is located between the front and back sides of the molding compound. The molding compound has multiple through holes that penetrate the molding compound along its thickness direction and are filled with conductive material. The first structure is located on the front side of the molding compound and is electrically connected from the front side of the molding compound to the conductive material in the through holes and the heat dissipation structure. The second structure is located on the back side of the molding compound and is electrically connected from the back side of the molding compound to the conductive material in the through holes and the heat dissipation structure. The optical chip is located on the first structure and is electrically connected to the first structure, and is also optically connected to the front side of the light guide structure. The optical guide structure of the present invention has virtually no optical signal loss during the entire process of transmitting optical signals, greatly reducing the transmission loss of optical signals transmitted by the optical guide structure; furthermore, by embedding the optical guide structure and heat dissipation structure in the molding layer, the heat dissipation capacity can be improved. The first structure and the second structure are directly formed on both sides of the molding layer, so that the silicon photonics packaging device of this embodiment replaces the PCB substrate and optical path, improving space utilization, reducing the size of the silicon photonics packaging device, and thus saving space.

[0081] Furthermore, it should be noted that, unless otherwise specified or indicated, the terms "first" and "second" in the specification are used only to distinguish the various components, elements, steps, etc. in the specification, and are not used to indicate the logical or sequential relationships between the various components, elements, steps, etc.

[0082] It is understood that although the present invention has been disclosed above with reference to preferred embodiments, these embodiments are not intended to limit the present invention. For any person skilled in the art, many possible variations and modifications can be made to the technical solutions of the present invention based on the disclosed technical content, or equivalent embodiments can be modified accordingly, without departing from the scope of the present invention. Therefore, any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the present invention shall still fall within the protection scope of the present invention.

Claims

1. A silicon photonics packaging device, characterized in that, It includes a light guide structure, a heat dissipation structure, a molding layer, a first structure, a second structure, and an optical chip. The optical guide structure is a right-angled trapezoidal structure with a front and a back side arranged opposite to each other. Its longitudinal section includes a first bottom edge and a second bottom edge arranged opposite to each other, and a first side edge and a second side edge arranged opposite to each other. The first bottom edge is located on the front side of the optical guide structure, and the second bottom edge is located on the back side of the optical guide structure. The length of the first bottom edge is greater than the length of the second bottom edge, and the angle between the first bottom edge and the first side edge is 90°. The angle between the first bottom edge and the second side edge is around 45°. The optical guide structure is connected to an optical fiber in the plane where the first side edge is located. The surface where the second side edge is located is a total reflection surface, which can totally reflect the optical signal entering the optical guide structure from the surface where the first side edge is located in a direction parallel to the front side to the plane where the first bottom edge is located. The heat dissipation structure is spaced apart from the light guide structure and embedded in the molding layer. The heat dissipation structure has a front and a back that are arranged opposite to each other, and the second side is located between the heat dissipation structure and the first side. The molding compound has a front and a back side disposed opposite to each other, and a first side side and a second side side disposed opposite to each other. The light guide structure, the heat dissipation structure and the front side of the molding compound are disposed on the same side. The first side side of the molding compound is disposed parallel to the plane containing the first side edge, and the first side edge is located between the first side side and the second side side. The front side of the molding compound exposes the front side of the light guide structure and the front side of the heat dissipation structure. The back side of the molding compound exposes the back side of the heat dissipation structure. The back side of the light guide structure is located between the front side and the back side of the molding compound. The molding compound has a plurality of through holes that penetrate the molding compound along the thickness direction and are filled with conductive material. The first structure is located on the front side of the molding compound, and the first structure is electrically connected from the front side of the molding compound to the conductive material in the through hole and the heat dissipation structure; The second structure is located on the back side of the molding compound, and the second structure is electrically connected from the back side of the molding compound to the conductive material in the through-hole and the heat dissipation structure; and The optical chip is located on the first structure and is electrically connected to the first structure, and is also connected to the front light of the light guide structure.

2. The silicon photonics packaging device as described in claim 1, characterized in that, The angle between the first bottom edge and the second side edge is 45°.

3. The silicon photonics packaging device as described in claim 1, characterized in that, The light guide structure includes a light conductor and a low-reflectivity coating applied to the surface of the light conductor. The light conductor is made of glass, and the reflectivity of the low-reflectivity coating is lower than that of the light conductor, so that a light signal entering the light guide structure from the surface of the first side parallel to the front of the light guide structure is totally reflected to the plane of the first bottom edge by the plane of the second side.

4. The silicon photonics packaging device as described in claim 3, characterized in that, The optical guide structure has a connection port on the plane of the first side, the connection port is used to connect an optical fiber, and the low reflectivity coating at the connection port exposes the optical conductor.

5. The silicon photonics packaging apparatus as described in claim 4, characterized in that, A guide groove is provided on the front side of the molding layer, the guide groove passes through the molding layer between the first side and the connection port, and the optical fiber is placed in the guide groove.

6. The silicon photonics packaging apparatus as described in claim 5, characterized in that, The guide groove is a V-shaped groove.

7. The silicon photonics packaging apparatus as described in claim 4, characterized in that, The front side of the light guide structure has a light outlet, and the low reflectivity coating at the light outlet exposes the light conductor. The light outlet is used to connect to the optical chip, and after total internal reflection of the light signal entering the light guide structure from the connection port in a direction parallel to the front side of the light guide structure, it is transmitted to the optical chip in a direction perpendicular to the front side of the light guide structure through the light outlet.

8. The silicon photonics packaging apparatus as described in claim 7, characterized in that, The shape of the light outlet is circular or square.

9. The silicon photonics packaging apparatus as described in claim 7, characterized in that, The optical chip has an optical connection port and an electrical connection port. The optical connection port is optically connected to the light output port, and the electrical connection port is electrically connected to the first structure.

10. The silicon photonics packaging apparatus as described in claim 1, characterized in that, The thickness of the optical guide structure is 100 micrometers to 150 micrometers.

11. The silicon photonics packaging apparatus as claimed in claim 1, characterized in that, The first structure includes a first passivation layer, a first metal layer, and a second passivation layer sequentially formed on the front side of the molding compound. The first passivation layer covers the front side of the molding compound, the front side of the heat dissipation structure, and the front side of the light guide structure, and exposes the conductive material in the through hole, a part of the front area of ​​the heat dissipation structure, the light outlet of the light guide structure, and the guide groove on the front side of the molding compound from the front side of the molding compound. The first metal layer is located on a portion of the first passivation layer. The first metal layer includes a plurality of first solder pads, which are electrically connected to the conductive material and the heat dissipation structure in the through-hole, respectively. as well as The second passivation layer covers the first passivation layer and the first metal layer. At least two first connection holes are formed in the second passivation layer. The first connection holes expose the first metal layer and are filled with conductive material for electrically connecting the optical chip.

12. The silicon photonics packaging apparatus as described in claim 1, characterized in that, This includes a third passivation layer, a second metal layer, and a fourth passivation layer sequentially formed on the back side of the molding compound. The third passivation layer covers the back side of the molding compound and the back side of the heat dissipation structure, and exposes the conductive material in the via and a portion of the back side of the heat dissipation structure from the back side of the molding compound; The second metal layer includes a plurality of second solder pads, which are located on a portion of the third passivation layer and are electrically connected to the conductive material in the via and the heat dissipation structure, respectively. as well as The fourth passivation layer covers the third passivation layer and the second metal layer. The fourth passivation layer has at least two second connection holes, which expose the second metal layer. The second connection holes are filled with conductive material, which is used for electrical connection to external circuits.

13. A method for fabricating a silicon photonics packaging device, using the silicon photonics packaging device as described in claim 1, characterized in that, Includes the following steps: A light guide structure and a heat dissipation structure to be packaged are provided. The light guide structure is a right-angled trapezoidal structure with a front and a back side arranged opposite to each other. Its longitudinal section includes a first bottom edge and a second bottom edge arranged opposite to each other, and a first side edge and a second side edge arranged opposite to each other. The first bottom edge is located on the front side of the light guide structure, and the second bottom edge is located on the back side of the light guide structure. The length of the first bottom edge is greater than the length of the second bottom edge, and the angle between the first bottom edge and the first side edge is 90°. The angle between the first bottom edge and the second side edge is around 45°. An optical fiber is connected to the plane where the first side edge is located. The surface where the second side edge is located is a total internal reflection surface, which can totally reflect the light signal entering the light guide structure from the surface where the first side edge is located in a direction parallel to the front side to the plane where the first bottom edge is located. The heat dissipation structure has a front and a back side arranged opposite to each other, and the second side edge is located between the heat dissipation structure and the first side edge. A first carrier plate is provided, and a first adhesive layer is formed on one side of the first carrier plate. The light guide structure and the heat dissipation structure are placed on the first adhesive layer at intervals, wherein the front sides of the heat dissipation structure and the light guide structure both face the first adhesive layer. A molding compound is filled between the light guide structure and the heat dissipation structure, and the molding compound is cured to form a molding layer. The molding layer has a front and a back side disposed opposite to each other, as well as a first side side and a second side side disposed opposite to each other. The light guide structure, the heat dissipation structure, and the front side of the molding layer are disposed on the same side. The first side side of the molding layer is disposed parallel to the plane containing the first side side, and the first side side is located between the first side side and the second side side. The front side of the molding layer exposes the front side of the light guide structure and the front side of the heat dissipation structure. The back side of the molding layer exposes the back side of the heat dissipation structure. The back side of the light guide structure is located between the front side and the back side of the molding layer. Remove the first carrier board; A plurality of through-holes are formed in the molding compound, the through-holes penetrating the molding compound along its thickness direction, and the through-holes are filled with conductive material; a first structure is formed on the front side of the molding compound, the first structure being electrically connected from the front side of the molding compound to the conductive material in the through-holes and the heat dissipation structure; a second structure is formed on the back side of the molding compound, the second structure being electrically connected from the back side of the molding compound to the conductive material in the through-holes and the heat dissipation structure; and An optical chip is provided, which is fixed on the first structure and electrically connected to the first structure, and is also connected to the front light of the light guide structure.

14. The method for fabricating the silicon photonics packaging device as described in claim 13, characterized in that, A guide groove is also formed in the molding compound, the guide groove being located on the front side of the molding compound and penetrating the molding compound between the first side and the connection port, thus exposing the connection port.

15. The method for fabricating the silicon photonics packaging device as described in claim 13, characterized in that, The optical chip has an optical connection port and an electrical connection port. The optical connection port is optically connected to the light output port of the light guide structure, and the electrical connection port is electrically connected to the first structure.

Images