Optical module of flip chip
The flip-chip optical module design with integrated lenses and optical fiber connections addresses signal distortion issues in existing packaging by minimizing interconnect length, enhancing transmission performance and efficiency.
Patent Information
- Application Number
- CN202510262246.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-03-06
- Publication Date
- 2025-07-15
AI Technical Summary
In the existing flip-flop process device packaging scheme, the optoelectronic chip interconnection lines are longer, resulting in signal distortion and a long optical path, which affects the transmission performance of the optical module.
The flip chip process is adopted to fix the DSP chip and VCSEL chip on the silicon adapter board, and the electrical signal is connected through the conductive channel. The optical path connection is achieved by combining the optical fiber jumper with its own lens, shortening the length of the interconnection line, and optimizing the optical path using lenses and reflective surfaces.
It realizes the shortest length of high-speed interconnection lines between optoelectronic chips, minimizes high-speed electrical signal distortion, improves the transmission performance of optical modules, and has a compact optical path structure, small space and high coupling efficiency.
Smart Images
Figure CN120322053A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of optical modules, and in particular to a flip-chip optical module. Background Art
[0002] Several technical solutions used in semiconductor packaging include chip bonding, wire bonding, and flip chip connection technology. Wire bonding and flip chip bonding are the most common. The wire bonding connection method is to place the front side of the chip upwards and connect the chip to the circuit board through gold wires. Flip chip technology is to solder the components downwards to the substrate, carrier or circuit board through the bumps on the chip. Flip chip connection is increasingly widely used in the packaging industry due to its compact structure and high reliability.
[0003] At present, the common flip-chip device packaging solution is to flip the DSP chip on the glass transfer board, place the VCSEL chip / PD chip on the top of the glass transfer board, open a through hole on the glass transfer board to connect the electrical signal of the DSP chip below to the top, and the VCSEL chip / PD chip is electrically connected by wire bonding, and a collimating / focusing lens is formed on the lens. The disadvantage of this solution is that the interconnection line of the optoelectronic chip is long, which is easy to cause signal distortion and the optical path is long. Summary of the invention
[0004] The object of the present invention is to provide a flip-chip optical module, which can achieve the shortest length of high-speed interconnection lines between optoelectronic chips, minimize the distortion of high-speed electrical signals, and effectively improve the transmission performance of the optical module.
[0005] To achieve the above-mentioned purpose, the technical solution of the present invention is a flip-chip optical module, comprising a PCB board, a DSP chip and a Vcsel chip, and also comprising a first silicon adapter board and a first optical fiber jumper with a built-in lens, wherein the first silicon adapter board and the first optical fiber jumper with a built-in lens are both arranged on the PCB board; the DSP chip and the Vcsel chip are both fixed on the bottom surface of the first silicon adapter board through a flip-chip process, and the DSP chip is connected to the Vcsel chip through an electrically conductive channel signal in the first silicon adapter board; the divergent light emitted by the Vcsel chip is collimated and reflected by the first silicon adapter board and then emitted into the first optical fiber jumper with a built-in lens.
[0006] As one of the implementation manners, the first silicon adapter board is provided with a first lens and a first reflecting surface. The first lens is disposed above the Vcsel chip and is used to collimate the divergent light emitted by the Vcsel chip and then emit it to the first reflecting surface. The first reflecting surface is disposed above the first lens and is used to receive the emitted light from the first lens and reflect it to the fiber jumper with the first self - contained lens.
[0007] As one of the implementation manners, the surface of the first lens is coated with an AR film.
[0008] As one of the implementation manners, the fiber jumper with the first self - contained lens includes a first substrate. One end of the first substrate is provided with a second lens, and the other end is connected to a first optical fiber. The second lens receives the emitted light from the first silicon adapter board and focuses it into the first optical fiber.
[0009] As one of the implementation manners, the optical module further includes a second silicon adapter board, a fiber jumper with a second self - contained lens, and a PD chip. The PD chip and the DSP chip are fixed on the bottom surface of the second silicon adapter board by a flip - chip process. The DSP chip and the PD chip are electrically connected through a conductive channel in the second silicon adapter board. The divergent light emitted by the fiber jumper with the second self - contained lens is reflected and focused by the second silicon adapter board and then enters the PD chip.
[0010] As one of the implementation manners, the second silicon adapter board is provided with a third lens and a second reflecting surface. The second reflecting surface is disposed above the third lens and is used to reflect the divergent light emitted by the fiber jumper with the second self - contained lens to the third lens. The third lens is disposed above the PD chip and is used to receive the reflected light from the second reflecting surface and focus it onto the PD chip.
[0011] As one of the implementation manners, the fiber jumper with the second self - contained lens includes a second substrate. One end of the second substrate is provided with a fourth lens, and the other end is connected to a second optical fiber. The fourth lens receives the divergent light emitted by the second optical fiber and emits it into the second silicon adapter board.
[0012] As one of the implementation manners, a converging lens is further disposed on the optical path between the fiber jumper with the second self - contained lens and the second silicon adapter board. The converging lens is fixed on the side surface of the second silicon adapter board.
[0013] As one of the implementation manners, the first silicon adapter board and the second silicon adapter board are of an integral structure, and / or the fiber jumper with the first self - contained lens and the fiber jumper with the second self - contained lens are of an integral structure.
[0014] As one of the implementation manners, the DSP chip is disposed on a heat sink.
[0015] Compared with the prior art, the present invention has the following beneficial effects:
[0016] (1) The present invention can achieve the shortest high-speed interconnection line length between optoelectronic chips, minimize the distortion of high-speed electrical signals to the greatest extent, and effectively improve the transmission performance of the optical module;
[0017] (2) The overall optical path structure layout of the present invention is compact, occupies little space in the vertical height direction, and can realize the optical path connection only through the silicon adapter board and the fiber optic jumper with a built-in lens. The optical path is short, the coupling process is simple, and both the TX optical path and the RX optical path have high coupling efficiency. BRIEF DESCRIPTION OF THE DRAWINGS
[0018] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.
[0019] Figure 1 Schematic diagram of the TX optical path of the flip-chip optical module provided by the embodiment of the present invention;
[0020] Figure 2 Schematic diagram of the RX optical path of the flip-chip optical module provided by the embodiment of the present invention;
[0021] Figure 3 Schematic diagram of the first lens and the third lens etched on the entire silicon adapter board provided by the embodiment of the present invention;
[0022] In the figure: 1, PCB board; 2, DSP chip; 3, Vcsel chip; 4, first silicon adapter board; 41, first lens; 42, first reflecting surface; 5, first fiber optic jumper with a built-in lens; 51, second lens; 52, first optical fiber; 6, PD chip; 7, second silicon adapter board; 71, third lens; 72, second reflecting surface; 8, second fiber optic jumper with a built-in lens; 81, fourth lens; 82, second optical fiber; 9, converging lens; 10, heat sink. DETAILED DESCRIPTION OF THE INVENTION
[0023] The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the drawings in the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, rather than all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the protection scope of the present invention.
[0024] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "center", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present invention.
[0025] The terms "first" and "second" are only used for descriptive purposes and should not be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of such features; in the description of the present invention, unless otherwise specified, the meaning of "a plurality" is two or more.
[0026] As Figure 1 shown, this embodiment provides a flip-chip optical module, which includes a PCB board 1, a DSP chip 2, and a Vcsel chip 3, and further includes a first silicon interposer 4 and a first fiber optic jumper 5 with a built-in lens. Both the first silicon interposer 4 and the first fiber optic jumper 5 with a built-in lens are disposed on the PCB board 1; both the DSP chip 2 and the Vcsel chip 3 are fixed on the bottom surface of the first silicon interposer 4 through a flip-chip process, and the DSP chip 2 and the Vcsel chip 3 are electrically connected through a conductive channel in the first silicon interposer 4; the divergent light emitted by the Vcsel chip 3 is collimated and reflected by the first silicon interposer 4 and then enters the first fiber optic jumper 5 with a built-in lens. In this embodiment, the DSP chip 2 and the Vcsel chip 3 are respectively packaged onto the bottom surface of the first silicon interposer 4 through a flip-chip process, and the DSP chip 2 and the Vcsel chip 3 are electrically connected through the conductive channel in the first silicon interposer 4, which can achieve the shortest length of the high-speed interconnection line between the optoelectronic chips, minimize the distortion of high-speed electrical signals to the greatest extent, and effectively improve the transmission performance of the TX component of the optical module.
[0027] Specifically, the PCB board 1 is provided with a first groove for accommodating the Vcsel chip 3 and a through groove for accommodating the DSP chip 2. When the first silicon interposer 4 is welded and fixed on the PCB board 1, the Vcsel chip 3 is exactly located in the first groove, and the DSP chip 2 is exactly located in the through groove.
[0028] Further, the first silicon interposer 4 is provided with a first lens 41 and a first reflecting surface 42. The first lens 41 is disposed above the Vcsel chip 3 and is used to collimate the divergent light emitted by the Vcsel chip 3 and then emit it to the first reflecting surface 42. The first reflecting surface 42 is disposed above the first lens 41 and is used to receive the outgoing light from the first lens 41 and reflect it to the fiber optic jumper 5 with a first built-in lens. As Figure 3 shown, in this embodiment, a dry etching process can be used to fabricate the first lens 41 and the first reflecting surface 42 on the first silicon interposer 4, so as to collimate the divergent light emitted by the Vcsel chip 3 and reflect the light in the vertical direction to the horizontal direction.
[0029] Optimally, an AR film is coated on the surface of the first lens 41. By coating an anti-reflection film on the surface of the first lens 41, reflection loss can be reduced and imaging quality can be improved.
[0030] Further, the fiber optic jumper 5 with a first built-in lens includes a first substrate. One end of the first substrate is provided with a second lens 51, and the other end is connected to a first optical fiber 52. The second lens 51 receives the outgoing light from the first silicon interposer 4 and focuses it into the first optical fiber 52. In this embodiment, the first substrate can be made of PEI (polyetherimide). A second lens 51 made of PEI material is provided at one end of the first substrate close to the first silicon interposer 4. The second lens 51 receives the light reflected by the first reflecting surface 42 and focuses it into the first optical fiber 52. Further, the end of the first optical fiber 52 is adhesively bonded in the first substrate, and the end of the first optical fiber 52 is processed into an angle of 0 degrees or 8 degrees by a laser cutting process, which can effectively reduce end face reflection and improve the transmission efficiency of optical signals.
[0031] As Figure 2 shown, in some embodiments, the optical module further includes a second silicon interposer 7, a fiber optic jumper 8 with a second built-in lens, and a PD chip 6. The PD chip 6 and the DSP chip 2 are fixed on the bottom surface of the second silicon interposer 7 by a flip-chip process. The DSP chip 2 and the PD chip 6 are electrically connected through a conductive channel in the second silicon interposer 7. The divergent light emitted by the fiber optic jumper 8 with a second built-in lens is reflected and focused by the second silicon interposer 7 and then enters the PD chip 6. In this embodiment, the DSP chip 2 and the PD chip 6 are respectively packaged on the bottom surface of the second silicon interposer 7 by a flip-chip process, and the DSP chip 2 and the PD chip are electrically connected through a conductive channel in the second silicon interposer 7, which can achieve the shortest length of the high-speed interconnection line between the optoelectronic chips, minimize the distortion of high-speed electrical signals to the greatest extent, and effectively improve the transmission performance of the RX component of the optical module.
[0032] Specifically, the PCB board 1 is provided with a second groove for accommodating the PD chip 6. When the second silicon adapter board 7 is welded and fixed on the PCB board 1, the PD chip 6 is exactly located in the second groove.
[0033] Further, the second silicon adapter board 7 is provided with a third lens 71 and a second reflecting surface 72. The second reflecting surface 72 is disposed above the third lens 71 and is used for reflecting the divergent light emitted by the fiber jumper 8 with the second self - contained lens to the third lens 71. The third lens 71 is disposed above the PD chip 6 and is used for receiving the reflected light from the second reflecting surface 72 and focusing it onto the PD chip 6. As Figure 3 shown, in this embodiment, a dry etching process can be used to fabricate the second reflecting surface 72 and the third lens 71 on the second silicon adapter board 7, so as to reflect the horizontal light emitted by the fiber jumper 8 with the second self - contained lens in the vertical direction and focus it on the PD chip 6.
[0034] Further, the fiber jumper 8 with the second self - contained lens includes a second base body. One end of the second base body is provided with a fourth lens 81, and the other end is connected with a second optical fiber 82. The fourth lens 81 receives the divergent light emitted by the second optical fiber 82 and emits it into the second silicon adapter board 7. In this embodiment, the second base body can be made of PEI (polyetherimide). The fourth lens 81 made of PEI is disposed at one end of the second base body close to the second silicon adapter board 7. The fourth lens 81 can preliminarily focus the divergent light emitted by the second optical fiber 82. Further, the end of the second optical fiber 82 is adhesively bonded in the second base body by glue, and the end of the second optical fiber 82 is processed into an angle of 0 degrees or 8 degrees by a laser cutting process, which can effectively reduce the end - face reflection and improve the transmission efficiency of the optical signal.
[0035] In some embodiments, a converging lens 9 is further disposed on the optical path between the fiber jumper 8 with the second self - contained lens and the second silicon adapter board 7. The converging lens 9 is fixed on the side surface of the second silicon adapter board 7. Specifically, it can be determined whether to set the converging lens 9 according to the actual optical path length. When the actual optical path length is long, the converging lens 9 can be adhesively bonded and fixed on the side surface of the second silicon adapter board 7 facing the fourth lens 81 by optical path glue, so as to further focus the light preliminarily focused by the fourth lens 81, reduce divergence, and improve the light intensity and imaging quality. When the actual optical path length is short, the converging lens 9 may not be set between the fourth lens 81 and the second reflecting surface 72, so as to reduce the system complexity and cost.
[0036] In this embodiment, the DSP chip 2, the Vcsel chip 3, and the PD chip 6 all select models that support the flip - chip process; the first lens 41, the second lens 51, the third lens 71, and the fourth lens 81 are all aspherical lenses; the converging lens 9 is a converging silicon lens.
[0037] Preferably, the first silicon adapter board 4 and the second silicon adapter board 7 are of an integral structure, and / or the first fiber optic jumper with a built-in lens 5 and the second fiber optic jumper with a built-in lens 8 are of an integral structure. In this embodiment, the first silicon adapter board 4 and the second silicon adapter board 7 are of an integral structure to form the entire silicon adapter board, which is integrally assembled onto the PCB board 1 and electrically connected to the PCB board 1. The Vcsel chip 3, the PD chip 6, and the DSP chip 2 are all assembled onto the electroplated pads on the bottom surface of the entire silicon adapter board through the flip-chip process. Conductive channels are provided inside the entire silicon adapter board to connect the DSP chip 2 with the Vcsel chip 3 and the PD chip 6; the first substrate of the first fiber optic jumper with a built-in lens 5 and the second substrate of the second fiber optic jumper with a built-in lens 8 are of an integral structure to form the entire fiber optic jumper with a built-in lens, which is integrally fixed onto the PCB board 1 with UV glue; by using the silicon adapter board and the fiber optic jumper with a built-in lens of an integral structure, the assembly process can be simplified, and the assembly efficiency and connection reliability can be improved.
[0038] For the TX optical path of the optical module in this embodiment: the divergent light emitted by the Vcsel chip 3 is collimated along the vertical direction through the first lens 41 on the entire silicon adapter board, and then reflected to the horizontal direction through the first reflecting surface 42 on the entire silicon adapter board, and exits from the side surface (polished surface) of the entire silicon adapter board. The light after exiting is focused onto the end face of the first optical fiber 52 through the second lens 51 to complete the coupling.
[0039] For the RX optical path of the optical module in this embodiment: the divergent light emitted by the second optical fiber 82 is preliminarily focused after passing through the fourth lens 81 in the horizontal direction, then further focused through the external converging lens 9, then reflected to the vertical direction through the second reflecting surface 72 on the entire silicon adapter board, and finally focused by the third lens 71 on the entire silicon adapter board and received by the PD.
[0040] The manufacturing process of the optical module in this embodiment is as follows:
[0041] 1) The DSP chip 2, the Vcsel chip 3, and the PD chip 6 are encapsulated onto the entire silicon adapter board through the flip-chip process, which can achieve high-precision positioning;
[0042] 2) The entire silicon adapter board is welded and fixed onto the PCB board 1;
[0043] 3) Couple the entire fiber optic jumper with a built-in lens;
[0044] 4) Use UV glue to bond the entire fiber optic jumper with a built-in lens onto the PCB board 1.
[0045] The overall optical path structure of the present invention is compact, occupies little space in the vertical height direction, and the optical path connection can be realized only through a silicon adapter board and an optical fiber jumper with a built-in lens. The optical path is short, the coupling process is simple, and both the TX optical path and the RX optical path have high coupling efficiency.
[0046] Further, the DSP chip 2 is disposed on the heat sink 10. As Figure 1 and Figure 2 shown, when the entire silicon adapter board is welded and fixed on the PCB board 1, the DSP chip 2 and the heat sink 10 are exactly located in the through groove on the PCB board 1, which can reduce the occupied space in the vertical direction, and the heat sink 10 is disposed below the DSP chip 2, which can effectively dissipate heat from the DSP chip 2 and ensure that the DSP chip 2 always operates within a suitable temperature range.
[0047] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.
Claims
1. An optical module with a flip-chip, comprising a PCB board, a DSP chip, and a Vcsel chip, characterized in that: It further includes a first silicon adapter board and a first fiber optic jumper with a built-in lens, both of which are disposed on the PCB board; the DSP chip and the Vcsel chip are both fixed on the bottom surface of the first silicon adapter board through a flip-chip process, and the DSP chip and the Vcsel chip are electrically connected through a conductive channel in the first silicon adapter board; The divergent light emitted by the Vcsel chip is collimated and reflected by the first silicon adapter board and then enters the first fiber optic jumper with a built-in lens.
2. The flip-chip optical module according to claim 1, characterized in that: The first silicon adapter board is provided with a first lens and a first reflecting surface. The first lens is disposed above the Vcsel chip and is used to collimate the divergent light emitted by the Vcsel chip and then emit it to the first reflecting surface; The first reflecting surface is disposed above the first lens and is used to receive the emitted light from the first lens and reflect it to the first fiber optic jumper with a built-in lens.
3. The optical module of the flip chip according to claim 2, characterized in that: The surface of the first lens is coated with an AR film.
4. The optical module of the flip chip according to claim 1, characterized in that: The first fiber optic jumper with a built-in lens includes a first base body. One end of the first base body is provided with a second lens, and the other end is connected to a first optical fiber; the second lens receives the emitted light from the first silicon adapter board and focuses it into the first optical fiber.
5. The optical module of the flip chip according to claim 1, characterized in that: It further includes a second silicon adapter board, a second fiber optic jumper with a built-in lens, and a PD chip. The PD chip and the DSP chip are both fixed on the bottom surface of the second silicon adapter board through a flip-chip process, and the DSP chip and the PD chip are electrically connected through a conductive channel in the second silicon adapter board; the divergent light emitted by the second fiber optic jumper with a built-in lens is reflected and focused by the second silicon adapter board and then enters the PD chip.
6. The optical module of the flip chip according to claim 5, characterized in that: The second silicon adapter board is provided with a third lens and a second reflecting surface. The second reflecting surface is disposed above the third lens and is used to reflect the divergent light emitted by the second fiber optic jumper with a built-in lens to the third lens; the third lens is disposed above the PD chip and is used to receive the reflected light from the second reflecting surface and focus it onto the PD chip.
7. The optical module of the flip chip according to claim 5, characterized in that: The second fiber optic jumper with a built-in lens includes a second base body. One end of the second base body is provided with a fourth lens, and the other end is connected to a second optical fiber; the fourth lens receives the divergent light emitted by the second optical fiber and emits it into the second silicon adapter board.
8. The optical module of the flip chip according to claim 5, characterized in that: A converging lens is further disposed on the optical path between the second fiber optic jumper with a built-in lens and the second silicon adapter board, and the converging lens is fixed on the side surface of the second silicon adapter board.
9. The optical module of the flip chip according to claim 5, characterized in that: The first silicon adapter board and the second silicon adapter board are of an integral structure, and / or the first fiber optic jumper with a built-in lens and the second fiber optic jumper with a built-in lens are of an integral structure.
10. The flip-chip optical module according to claim 1, wherein: The DSP chip is disposed on a heat sink.