Manufacturing method of optoelectronic module

Abstract

The present invention relates to a method for manufacturing an optoelectronic module, comprising the following steps: (1) preparing a first circuit substrate; (2) providing a first cladding layer on the first circuit substrate; (3) providing a core layer containing a photosensitive material on the first cladding layer, and irradiating the core layer with a light beam to expose and form a light path; (4) preparing a second cladding layer and a second circuit substrate, wherein the second circuit substrate is provided on one side of the core layer relative to the first circuit substrate, and the second cladding layer is located between the core layer and the second circuit substrate; (5) electrically connecting the first circuit substrate and the second circuit substrate with at least one conductive structure; and (6) fixing a plurality of optoelectronic elements on at least one of the first circuit substrate and the second circuit substrate.

Description

Technical Field

[0001] This invention relates to optoelectronic boards, and in particular to a method for manufacturing optoelectronic modules. Prior Technology

[0002] In the conventional optoelectronic board manufacturing process with optical waveguide, a cladding layer and a transmission layer are sequentially laminated or coated on a circuit board. An exposure pattern is then formed on the transmission layer using a photoresist. Part of the transmission layer is removed through processes such as development and etching to form an optical channel. Finally, a cladding layer is laminated onto the transmission layer to form an optical waveguide structure.

[0003] However, the aforementioned process steps are complex, time-consuming, and costly. Furthermore, in existing exposure processes, the Gaussian energy distribution of the laser beam results in poor edge sharpness of the exposed pattern, leading to uneven edges in the optical channel and affecting light transmission. In addition, existing optoelectronic boards can only accommodate optoelectronic components on one side, limiting their application and signal transmission efficiency. The coupling between optoelectronic components, optical channels, and copper wires also suffers from difficulties in alignment, time consumption, and poor coupling efficiency, all of which urgently require improvement.

[0004] Therefore, it is necessary to provide a novel and progressive method for manufacturing optoelectronic modules to solve the above-mentioned problems. Summary of the Invention

[0005] The main objective of this invention is to provide a method for manufacturing optoelectronic modules, which is simple in steps and can achieve high-speed signal transmission.

[0006] To achieve the above objectives, the present invention provides a method for manufacturing an optoelectronic module, comprising the following steps: (1) preparing a first circuit substrate; (2) providing a first cladding layer on the first circuit substrate; (3) providing a core layer containing a photosensitive material on the first cladding layer, and irradiating the core layer with a light beam to expose and form a light path; (4) preparing a second cladding layer and a second circuit substrate, wherein the second circuit substrate is located on one side of the core layer relative to the first circuit substrate, and the second cladding layer is located between the core layer and the second circuit substrate; (5) electrically connecting the first circuit substrate and the second circuit substrate with at least one conductive structure; and (6) fixing a plurality of optoelectronic elements on at least one of the first circuit substrate and the second circuit substrate. Simple Explanation of the Diagram

[0007] Figures 1 to 7 are schematic flowcharts of a first preferred embodiment of the present invention. Figures 8 to 14 are schematic flowcharts of a second preferred embodiment of the present invention. Figures 15 to 21 are schematic flowcharts of a third preferred embodiment of the present invention. Figures 22 to 28 are schematic flowcharts of a fourth preferred embodiment of the present invention. Implementation

[0008] The following examples illustrate possible implementations of the present invention, but are not intended to limit the scope of protection of the present invention. The use of "a" or "at least one" before the terms mentioned herein is not a limitation on the quantity, and may also be "multiple" depending on the requirements. Such variations in quantity are also within the scope of protection, and are therefore stated in advance.

[0009] Please refer to Figures 1 to 7, which show a first preferred embodiment of the present invention. The method for manufacturing the optoelectronic module 1 of the present invention includes the following steps.

[0010] Step (1): Prepare a first circuit board 10. The first circuit board 10 can be a rigid board (RPCB) or a flexible board (FPC), and can also be a single-sided board, double-sided board or multilayer board as required. In this step (1), a first optical port 11 and a second optical port 12 are provided on the first circuit board 10.

[0011] Step (2): A first cladding layer 20 is applied to the first circuit board 10. A cladding material can be coated on the first circuit board 10 and embedded in the first optical port 11 and the second optical port 12, and then the cladding material can be photocured or thermally cured to form the first cladding layer 20. Alternatively, the cladding material can be pre-formed into a dry film and then directly laminated to the first circuit board 10 to form the first cladding layer 20.

[0012] Step (3): A core layer 30 containing a photosensitive material is placed on the first coating layer 20, and a light beam is used to irradiate the core layer 30 to form an optical path 31, as shown in Figures 1 and 2. The photosensitive material is, for example, but not limited to, positive dry film photoresist, negative dry film photoresist, photosensitive film, etc. In detail, step (3) further includes: dividing the core layer 30 into a plurality of imaging units arranged in a matrix; providing an exposure image, and classifying each imaging unit into a light-receiving area or a non-light-receiving area according to the exposure image; and irradiating at least a portion of the light-receiving areas with the light beam to form the optical path 31. Depending on the photosensitivity of the selected photosensitive material, after exposure, the refractive index of each light-receiving area is greater than the refractive index of each non-light-receiving area, and the light-receiving areas form the optical path 31; or, after exposure, the refractive index of each light-receiving area is less than the refractive index of each non-light-receiving area, and the non-light-receiving areas form the optical path 31.

[0013] It should be noted that in this embodiment, a maskless exposure technique is used. By adjusting the proportion of the total number of light-receiving areas irradiated by the light beam, the light dose gradient at the boundary between the light-receiving and non-light-receiving areas is adjusted, thereby enabling the optical path 31 to obtain sharp edges through a single exposure. For example, the light beam can be reflected to the light-receiving areas via a digital micromirror element (DMD), so that 25%, 50%, 75%, or 100% of the total number of light-receiving areas are irradiated by the light beam and have a different refractive index than the non-light-receiving areas. Each light-receiving area is either irradiated only once or not irradiated at all. The unirradiated light-receiving areas can be exposed by the light energy of the adjacent and exposed light-receiving areas. Without the use of a mask, and without further development and etching steps, the optical path 31 can be directly baked and shaped to obtain the optical path 31. The operation is time-saving, cost-effective, and can effectively improve the edge sharpness of the optical path. Whether each of the light-receiving areas is exposed by the light beam can be randomly selected, manually set, or selected according to preset rules. Preferably, at least one of the first coating layer 20 and the first circuit board 10 is selected from materials that include a light-absorbing material. The light-absorbing material is used to absorb at least a portion of the light beam, for example, it can absorb light of a specific wavelength, thereby reducing the reflection of the light beam to the core layer 30 through the first coating layer 20 or the first circuit board 10 in step (3), which helps to improve the edge sharpness of the light path 31.

[0014] Step (4): Prepare a second cladding layer 40 and a second circuit board 50. The second circuit board 50 is located on the side of the core layer 30 opposite to the first circuit board 10, and the second cladding layer 40 is positioned between the core layer 30 and the second circuit board 50. Similarly, the second circuit board 50 can be a rigid PCB or a flexible PCB, or a single-sided, double-sided, or multilayer board as required. The second cladding layer 40 can be first bonded to the core layer 30, and then the second circuit board 50 can be deposited on the second cladding layer 40; or, the second cladding layer 40 can be first bonded to the second circuit board 50, and then deposited together on the core layer 30, as shown in Figures 3 and 4. Therefore, the first cover layer 20, the core layer 30 and the second cover layer 40 can not only be used to transmit optical signals, but also serve as dielectric layers. They also have the function of bonding the first circuit board 10 and the second circuit board 50. No additional adhesive is needed, which effectively simplifies the processing steps and reduces the processing cost.

[0015] Step (5): The first circuit board 10 and the second circuit board 50 are electrically connected by at least one conductive structure 60, as shown in FIG5. In this step (5), at least one through hole 61 is formed through the first circuit board 10, the first cladding layer 20, the core layer 30, the second cladding layer 40 and the second circuit board 50, and a conductor 62 is provided in each through hole 61. The conductor 62 is, for example, but not limited to, a solid or hollow conductive pillar, a conductive plating layer, etc., so as to realize the electrical signal conduction between the first circuit board 10 and the second circuit board 50.

[0016] Step (6): Fix a plurality of optoelectronic elements 70 onto at least one of the first circuit board 10 and the second circuit board 50, as shown in FIG7. In this step (6), two optoelectronic elements 70 are connected to the first circuit board 10 corresponding to the first optical port 11 and the second optical port 12, respectively. The plurality of optoelectronic elements 70 may include, for example, top emitting VCSELs, bottom emitting VCSELs, driver ICs, photodetectors, transimpedance amplifiers (TIAs), etc., and can be selected as needed.

[0017] Furthermore, after step (5), two grooves 80 extending from one of the first circuit board 10 and the second circuit board 50 toward the core layer 30, and two inclined surfaces 81 respectively located within the two grooves 80, are formed on each inclined surface 81; the two grooves 80 are respectively located on opposite sides of the first light port 11 and the second light port 12. Each light-reflecting surface can be, for example, formed by depositing a metal coating on an inclined surface 81, so that light signals can be transmitted between each optoelectronic element 70 and the core layer 30.

[0018] The optoelectronic module 1 can be manufactured through the aforementioned steps. The steps are simple and time-saving, and it can realize high-speed signal transmission between the first circuit board 10 and the second circuit board 50, with a wide range of applications. It should be noted that the first circuit board 10 and the first cladding layer 20, and the second circuit board 50 and the second cladding layer 40 are not limited to being directly stacked in contact. They can also be indirectly stacked with other structures as needed.

[0019] Preferably, in step (1), at least one first positioning hole 13 is further formed in the first circuit substrate 10; in step (3), at least one reference positioning pattern 32 corresponding to the at least one first positioning hole 13 is further exposed in the core layer 30; in step (4), at least one second positioning hole 51 corresponding to the at least one reference positioning pattern 32 is further formed in the second circuit substrate 50, and one of the first positioning holes 13, one of the reference positioning patterns 32 and one of the second positioning holes 51 are overlapped in one thickness direction of the first circuit substrate 10 to form a phototarget positioning reference S1. The first circuit substrate 10 and the second circuit substrate 50 each include a conductive layer 14, 52. Before step (6), the conductive layers 14, 52 of the first circuit substrate 10 and the second circuit substrate 50 are etched according to the phototarget positioning reference S1 to form a plurality of electrical contacts 14a, 52a for connecting the plurality of optoelectronic elements 70. Since the reference positioning pattern 32 is constructed synchronously with the optical path 31, the optical target positioning reference S1 allows light to pass through and can be used as a positioning reference for making the plurality of electrical contacts 14a and 52a, thereby improving the positioning accuracy of the plurality of electrical contacts 14a and 52a. In this step (6), at least one of the photoelectric elements 70 is aligned and fixed according to the optical target positioning reference S1, resulting in good coupling effect. In this embodiment, the plurality of optoelectronic elements 70 includes a positively emitting VCSEL 71 and a control chip 72. The positively emitting VCSEL 71 only needs to be aligned with the first light port 11 according to the light target positioning reference S1 and fixed to the first circuit board 10, and then electrically connected to the control chip 72 by wire bonding, which is convenient for assembly. In other embodiments, the plurality of optoelectronic elements may also include a back-emitting VCSEL. The back-emitting VCSEL can be aligned with the first light port according to the light target positioning reference, and simultaneously aligned with the plurality of electrical contacts and connected to the first circuit board by flip-chip bonding.

[0020] Referring to Figures 8 to 14, the second preferred embodiment of the present invention differs from the aforementioned first preferred embodiment in that the plurality of optoelectronic elements 70 are disposed on the first circuit board 10a and the second circuit board 50a. Therefore, in step (1), a first optical port 11 is further provided on the first circuit board 10a; in step (4), a second optical port 53 is further provided on the second circuit board 50a; in step (6), one optoelectronic element 70 is connected to the first circuit board 10a corresponding to the first optical port 11, and another optoelectronic element 70 is connected to the second circuit board 50a corresponding to the second optical port 53. In this embodiment, the plurality of optoelectronic elements 70 may include a positively emitting VCSEL 71, a control chip 72, a light receiver 73, and a cross-group amplifier 74. The positively emitting VCSEL 71 and the control chip 72 are disposed on the first circuit board 10a, and the light receiver 73 and the cross-group amplifier 74 are disposed on the second circuit board 50a, thereby enabling the transmission of optoelectronic signals on opposite sides of the optoelectronic module 1a. In other embodiments, the plurality of optoelectronic elements may also be selected from other types of light emitters, light receivers, and other related components as needed.

[0021] Referring to Figures 15 to 21, the third preferred embodiment of the present invention differs from the aforementioned first preferred embodiment in that: in step (1), at least one third positioning hole 15 is formed on the side of the first circuit substrate 10b opposite to one of the conductive layers 14, 52, and the conductive layers 14, 52 are etched to form a plurality of electrical contacts 14a, 52a and at least one corresponding fourth positioning hole 16 communicating with the at least one third positioning hole 15. The communicating third positioning hole 15 and the fourth positioning hole 16 have different radial dimensions and constitute a substrate positioning reference S2. In step (3), the irradiation area of ​​the light beam is determined based on the substrate positioning reference S2, that is, the forming position of the exposure pattern on the core layer 30 is determined based on the substrate positioning reference S2. Since the at least one fourth positioning hole 16 is formed synchronously with the plurality of electrical contacts 14a, 52a, when viewing the substrate positioning reference S2 along one of the thickness directions of the conductive layers 14, 52, the hole wall of the at least one fourth positioning hole 16 can be seen, and thus can be used as a positioning reference for making the optical path 31, so that the optical path 31 is accurately aligned with the plurality of electrical contacts 14a, 52a.

[0022] In this embodiment, in step (3), at least one reference positioning pattern 32 corresponding to the substrate positioning references S2 is exposed and formed on the core layer 30; in step (4), at least one fifth positioning hole 54 corresponding to the at least one reference positioning pattern 32 is passed through the second circuit substrate 50b, and one third positioning hole 15, one fourth positioning hole 16, one reference positioning pattern 32 and one fifth positioning hole 54 are overlapped in the thickness direction of the first circuit substrate 10b to form a light target positioning reference S1a. In this way, the plurality of optoelectronic elements 70 can also be connected according to the light target positioning reference S1a in step (6) to facilitate photocoupling. In other embodiments, each substrate positioning reference can also be configured in a staggered manner with the light target positioning reference as in one of the first preferred embodiments; the optoelectronic module can also only have the light target positioning reference or the substrate positioning reference.

[0023] Referring to Figures 22 to 28, one of the fourth preferred embodiments of the present invention differs from the aforementioned third preferred embodiment in that the plurality of optoelectronic elements 70 are respectively disposed on the first circuit board 10c and the second circuit board 50c. Similar to the aforementioned second preferred embodiment, by changing the position of the second optical port 53, optoelectronic signals can be transmitted on opposite sides of the optoelectronic module 1c.

[0024] 1, 1a, 1b, 1c: Optoelectronic modules 10, 10a, 10b, 10c: First circuit board 11: First optical port 12,53: Second optical port 13: First positioning hole 14,52: Conductive layer 14a, 52a: Electrical contacts 15: Third positioning hole 16: Fourth positioning hole 20: First cladding layer 30: Core Layer 31: Optical Pathway 32: Baseline Positioning Graphics 40: Second cladding layer 50, 50a, 50b, 50c: Second circuit board 51: Second positioning hole 54: Fifth positioning hole 60: Conductive Structure 61: Through hole 62: Conductor 70: Optoelectronic components 71: Positively Emitting VCSEL 72: Control chip 73: Optical Receiver 74: Cross-group amplifier 80: Groove 81: Incline S1, S1a: Target positioning reference S2: Substrate positioning reference

Claims

1. A method for manufacturing an optoelectronic module, comprising the following steps: (1) preparing a first circuit substrate; (2) disposing a first cladding layer on the first circuit substrate; (3) disposing a core layer containing a photosensitive material on the first cladding layer, and irradiating the core layer with a light beam to expose and form a light path; (4) preparing a second cladding layer and a second circuit substrate, wherein the second circuit substrate is disposed on one side of the core layer relative to the first circuit substrate, and the second cladding layer is located between the core layer and the second circuit substrate; (5) electrically connecting the first circuit substrate and the second circuit substrate with at least one conductive structure; and (6) fixing a plurality of optoelectronic elements on at least one of the first circuit substrate and the second circuit substrate. In step (1), at least one first positioning hole is provided in the first circuit substrate; in step (3), at least one reference positioning pattern corresponding to the at least one first positioning hole is exposed in the core layer; in step (4), at least one second positioning hole corresponding to the at least one reference positioning pattern is provided in the second circuit substrate, and one of the first positioning holes, one of the reference positioning patterns and one of the second positioning holes are overlapped in one thickness direction of the first circuit substrate to form a phototarget positioning reference.

2. The optoelectronic module manufacturing method as claimed in claim 1, wherein in step (1), a first optical port and a second optical port are further provided on the first circuit board; and in step (6), two optoelectronic components are respectively connected to the first circuit board corresponding to the first optical port and the second optical port.

3. The optoelectronic module manufacturing method as claimed in claim 1, wherein in step (1), a first optical port is further provided in the first circuit board; in step (4), a second optical port is further provided in the second circuit board; and in step (6), an optoelectronic element is connected to the first circuit board corresponding to the first optical port, and another optoelectronic element is connected to the second circuit board corresponding to the second optical port.

4. The optoelectronic module manufacturing method as described in claim 2 or 3, wherein two grooves extending from one of the first circuit board and the second circuit board toward the core layer and two inclined surfaces respectively located in the two grooves are further formed, and a light reflecting surface is formed on each of the inclined surfaces; the two grooves are respectively located on opposite sides of the first light port and the second light port.

5. The optoelectronic module manufacturing method as claimed in claim 1, wherein in step (5), at least one through hole is formed through the first circuit board, the first cladding layer, the core layer, the second cladding layer and the second circuit board, and a conductor is provided in each of the through holes.

6. The method for manufacturing an optoelectronic module as claimed in claim 1, wherein step (3) further includes: The core layer is divided into a matrix of multiple imaging units; an exposure image is provided, and each imaging unit is divided into a light-receiving area or a non-light-receiving area based on the exposure image; and at least a portion of the light-receiving areas are illuminated by the light beam to form the light path.

7. The optoelectronic module manufacturing method as claimed in claim 6, wherein after step (3), the refractive index of each of the light-receiving areas is greater than the refractive index of each of the non-light-receiving areas, and the light-receiving areas form the optical path.

8. The method for manufacturing an optoelectronic module as claimed in claim 6, wherein after step (3), the refractive index of each of the light-receiving areas is less than the refractive index of each of the non-light-receiving areas, and the non-light-receiving areas form the optical path.

9. The method for manufacturing an optoelectronic module as claimed in claim 1, wherein at least one of the first cladding layer and the first circuit board is selected from those comprising a light-absorbing material for absorbing at least a portion of the light beam.

10. The method for manufacturing an optoelectronic module as claimed in claim 1, wherein the first circuit board and the second circuit board each include a conductive layer, and before step (6), the conductive layers of the first circuit board and the second circuit board are further etched according to the phototarget positioning reference to form a plurality of electrical contacts for connecting the plurality of optoelectronic elements.

11. The method for manufacturing an optoelectronic module as claimed in claim 1, wherein in step (6), at least one optoelectronic element is aligned and fixed according to the optical target positioning reference.

12. A method for manufacturing an optoelectronic module, comprising the following steps: (1) preparing a first circuit substrate; (2) disposing a first cladding layer on the first circuit substrate; (3) disposing a core layer containing a photosensitive material on the first cladding layer, and irradiating the core layer with a light beam to expose and form a light path; (4) preparing a second cladding layer and a second circuit substrate, wherein the second circuit substrate is disposed on one side of the core layer relative to the first circuit substrate, and the second cladding layer is located between the core layer and the second circuit substrate; (5) electrically connecting the first circuit substrate and the second circuit substrate with at least one conductive structure; and (6) fixing a plurality of optoelectronic elements on at least one of the first circuit substrate and the second circuit substrate; The first circuit board includes a conductive layer. In step (1), at least one third positioning hole is formed on one side of the first circuit board relative to the conductive layer, and the conductive layer is etched to form a plurality of electrical contacts and at least one fourth positioning hole corresponding to and communicating with the at least one third positioning hole. The third positioning hole and the fourth positioning hole have different radial dimensions and form a substrate positioning reference.

13. The optoelectronic module manufacturing method as claimed in claim 12, wherein in step (3), the irradiation area of ​​the light beam is determined based on the substrate positioning reference.

14. The optoelectronic module manufacturing method as claimed in claim 12, wherein in step (3), at least one reference positioning pattern corresponding to the substrate positioning references is further exposed and formed on the core layer; and in step (4), at least one fifth positioning hole corresponding to the at least one reference positioning pattern is further provided on the second circuit substrate, and one third positioning hole, one fourth positioning hole, one reference positioning pattern and one fifth positioning hole are overlapped in one thickness direction of the first circuit substrate to form a phototarget positioning reference.

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