Substrate structure with optical waveguide in through hole and manufacturing method thereof

Abstract

The invention relates to a substrate structure with an optical waveguide in a through hole and a manufacturing method thereof, the substrate structure is provided with a core substrate layer, and the core substrate layer is provided with a through hole communicated between a first surface and a second surface which are opposite to each other; a through hole metal layer is formed on an inner wall surface of the through hole, and a through hole space for communicating the first surface and the second surface is reserved in the through hole of the through hole metal layer; the optical waveguide unit is formed in the through hole space of the through hole, and the optical waveguide unit is provided with a through hole optical waveguide; the substrate structure can transmit an electric signal through the through hole metal layer and transmit an optical signal through the through hole optical waveguide in the same through hole at the same time, so that the layout space for arranging the through hole in a photoelectric hybrid board is saved, and the electric signal and the optical signal are transmitted in a more integrated manner.

Description

Technical Field

[0001] This invention relates to a substrate structure and its fabrication method, particularly a substrate structure with an optical waveguide within a through-hole and its fabrication method. Background Technology

[0002] With the development of technology, the signals that electronic components need to transmit are becoming increasingly high-frequency and high-speed. For a substrate, this also needs to adapt to this trend by increasing the number of input / output (I / O) interfaces, using fine-pitch bonding, and adding optical waveguides to guide the transmission of optical and electrical signals. Such a substrate capable of transmitting optical and electrical signals can be called an optoelectronic hybrid board. To transmit these optical and electrical signals, a multilayer optoelectronic hybrid board, such as a build-up substrate with a core layer, will have vias for electrical signal transmission, forming a conductive path between layers, and optical waveguides for optical signal transmission, forming a light-guiding path.

[0003] However, because the optical signal and the electrical signal are transmitted through different media, even when integrated into the optoelectronic hybrid board, they still operate as separate, independently configured channels. Therefore, within the limited space of the optoelectronic hybrid board, the wiring volume of the circuit and the optical path is currently mutually constrained. Given the limited space occupied by the conductive path and the light guide path, and with the increasing demand for I / O interfaces, the optoelectronic hybrid board needs improvement to achieve more efficient wiring for transmitting the electrical and optical signals. Summary of the Invention

[0004] The present invention provides a substrate structure with an optical waveguide inside a through-hole and a method for manufacturing the same, which enables an electrical signal and an optical signal to be transmitted through the same channel structure, thereby saving the layout space of a through-hole in an optoelectronic hybrid board and improving the situation in the existing optoelectronic hybrid board where the circuit and optical paths are independent and mutually restrict the layout space.

[0005] The substrate structure of the present invention includes:

[0006] A core substrate layer having a first surface and a second surface opposite to each other;

[0007] A through hole penetrates the core substrate layer to connect the first surface and the second surface, and has an inner wall surface;

[0008] A through-hole metal layer is formed on the inner wall surface of the through-hole, and a through-hole space is left in the through-hole to connect the first surface and the second surface;

[0009] An optical waveguide unit is formed in the through-hole space of the through-hole and has a through-hole optical waveguide.

[0010] The method for manufacturing the substrate structure of the present invention includes the following steps:

[0011] A through-hole is formed by penetrating a first surface and a second surface of a core substrate layer to connect the opposing first surface and the second surface.

[0012] A through-hole metal layer is formed on one inner wall surface of the through hole, and a through-hole space connecting the first surface and the second surface is left in the through hole;

[0013] An optical waveguide unit is formed in the through-hole space of the through-hole; wherein the optical waveguide unit has a through-hole optical waveguide.

[0014] By forming a via metal layer and a via optical waveguide within the via, an electrical signal can pass through the via via via through the metal layer, while an optical signal can also pass through the via via via in parallel through the optical waveguide. In other words, the via of this invention can simultaneously transmit the electrical signal through the via metal layer and the optical signal through the via optical waveguide. Thus, this invention significantly saves wiring space for both circuits and optical paths, and improves the situation where circuits and optical paths are independent and mutually restrictive in terms of wiring space, allowing the electrical and optical signals to be transmitted more integratedly. Attached Figure Description

[0015] The accompanying drawings are intended only to illustrate and explain the present invention and do not limit the scope of the invention.

[0016] in:

[0017] Figure 1 This is a cross-sectional schematic diagram of a core layer optical waveguide structure of the present invention.

[0018] Figure 2 This is a cross-sectional schematic diagram of the core layer optical waveguide structure of the present invention in the first embodiment.

[0019] Figures 3A to 3J These are schematic diagrams of each step in the fabrication process of the core layer optical waveguide structure of the present invention in the first embodiment.

[0020] Figure 4 This is a cross-sectional schematic diagram of the core layer optical waveguide structure of the present invention in a second embodiment.

[0021] Figures 5A to 5H These are schematic diagrams of each step in the fabrication process of the core layer optical waveguide structure of the present invention in the second embodiment.

[0022] Figure 6This is another cross-sectional schematic diagram of the core layer optical waveguide structure of the present invention in a second embodiment.

[0023] Figure 7 This is a cross-sectional schematic diagram of the core layer optical waveguide structure of the present invention in a third embodiment.

[0024] Figures 8A to 8G These are schematic diagrams of each step in the fabrication process of the core layer optical waveguide structure of the present invention in the third embodiment.

[0025] Figures 9A-9B These are two cross-sectional schematic diagrams of the core layer optical waveguide structure of the present invention in the third embodiment. Detailed Implementation

[0026] To provide a clearer understanding of the technical features, objectives, and effects of the present invention, specific embodiments of the present invention will now be described with reference to the accompanying drawings.

[0027] The present invention provides a substrate structure with an optical waveguide inside a through-hole and a method for manufacturing the same, which enables an electrical signal and an optical signal to be transmitted through the same channel, thereby saving the layout space of a through-hole in an optoelectronic hybrid board, improving the situation in the existing optoelectronic hybrid board where the circuit and optical paths are independent and mutually restrict the layout space, and enabling the electrical signal and the optical signal to be transmitted more integratedly in the substrate.

[0028] Please see Figure 1 and Figure 2 As shown, Figure 1 To illustrate a core substrate layer 10 in an optoelectronic hybrid board, the core substrate layer 10 has a first surface 11 and a second surface 12 opposite to each other. Preferably, the core substrate layer 10 is thick and tough enough to support multilayer circuits disposed on the first surface 11 and the second surface 12.

[0029] A through-hole 13 is formed on the core substrate layer 10, penetrating the core substrate layer 10 to connect the first surface 11 and the second surface 12, and the through-hole 13 has an inner wall surface 14. A conductive through-hole metal layer 15 is formed on the inner wall surface 14, but the through-hole metal layer 15 does not completely fill the through-hole 13, but leaves a through-hole space 16 in the through-hole 13. An optical waveguide unit 17 is formed in the through-hole space 16 of the through-hole 13, and the optical waveguide unit 17 has a through-hole optical waveguide 171.

[0030] Through the via metal layer 15 and the via optical waveguide 171 formed within the via 13, an electrical signal can pass through the via metal layer 15 along the via 13, while an optical signal can also pass through the via optical waveguide 171 along the same path. In other words, the via 13 of the present invention can simultaneously transmit the electrical signal through the via metal layer 15 and the optical signal through the via optical waveguide 171. Thus, the via 13, which can simultaneously transmit the electrical signal and the optical signal, saves wiring space in the circuit and optical paths, and enables more efficient transmission of the electrical signal and the optical signal within the limited space of the core substrate layer 10.

[0031] Please see Figure 2 and Figures 3A to 3J As shown, Figure 2 This is a cross-sectional schematic diagram of the core layer optical waveguide structure of the present invention in a first embodiment, and this is as follows. Figure 2 The core layer optical waveguide structure of the first embodiment shown is composed of, for example, Figures 3A to 3J The process is completed using a method shown in the flowchart.

[0032] Regarding the refractive index (index of refraction), according to Snell's Law, when light travels from a medium with a higher refractive index to a medium with a lower refractive index, and the angle of incidence is at least a critical angle, total internal reflection occurs, causing the light to be reflected and travel only through the medium with the higher refractive index. In this case, because the light is only reflected and travels through the same medium, the intensity of the light is not lost due to crossing different media.

[0033] To ensure the practicality of the optical signal transmission, the optical signal is limited to reflection and travel only within the via optical waveguide 171 when passing through the via 13, thereby reducing energy loss during transmission. In this first embodiment, the via optical waveguide 171 directly contacts the via metal layer 15.

[0034] The substrate structure of the present invention further comprises a redistribution layer (RDL) on the first surface 11 and the second surface 12 of the core substrate layer 10, and at least one of the redistribution layers comprises a line dielectric layer, a line metal layer and a line optical waveguide. For example, a first redistribution layer 110 is provided on the first surface 11 and a second redistribution layer 120 is provided on the second surface 12.

[0035] The first redistribution layer 110 includes a first line dielectric layer, a first line metal layer 113, a first line optical waveguide 114, a first redistribution layer surface 115 facing away from the core substrate layer 10, and at least one reflector 116. The first line dielectric layer includes a first circuit 111 and a first line dielectric material 112, with the first line dielectric material 112 covering the first circuit 111. The first redistribution layer surface 115 is respectively provided with a photoelectric element 200 for receiving or outputting the optical signal and an electronic element 300 for receiving or outputting the electrical signal.

[0036] The electronic component 300 is electrically connected to the first circuit 111 via its pins and corresponding electrode pads. Preferably, the electronic component 300 can be a die, and the electronic component 300 is electrically connected to the first line metal layer 113 via the first circuit 111, and further electrically connected to the via metal layer 15 via the first line metal layer 113. In detail, the core substrate layer 10 has a plurality of vias 13, and the via metal layer 15 in each via 13 is electrically connected to the first line metal layer 113. A portion of the first line metal layer 113 is formed between the first line dielectric material 112 and the core substrate layer 10, and is bonded to the first surface 11 of the core substrate layer 10, extending to connect to the via metal layer in one of the vias 13.

[0037] The first line optical waveguide 114 and at least one of the reflectors 116 form the optical path in the first redistribution layer 110. The first line optical waveguide 114 is covered by the first line dielectric material 112, and the first line optical waveguide 114 seamlessly connects to the optoelectronic element 200 and the through-hole optical waveguide 171 within each of the through-holes 13. A portion of the first line optical waveguide 114 is bonded to the first line metal layer 113 bonded to the core substrate layer 10. Thus, in Figure 2 In region 100 shown, the through-hole waveguide 171 within one of the through-holes 13 is perpendicular to the first surface 11. Through the placement of one of the reflectors 116 within the first line waveguide 114, the optical signal transmitted by the first line waveguide 114 and the through-hole waveguide 171 can bend at a 90-degree angle, changing from perpendicular to the first surface 11 to parallel to it. Preferably, the reflector 116 is positioned at a 45-degree angle relative to the first surface 11. The optical signal traveling in region 100 is reflected into the first line waveguide 114 upon contact with the heterogeneous first line dielectric material 112 and first line metal layer 113.

[0038] Similarly, the second redistribution layer 120 includes a second circuit dielectric layer, a second circuit metal layer 123, a second circuit optical waveguide 124, a second redistribution layer surface 125 facing away from the core substrate layer 10, and at least one reflector 126. The second circuit dielectric layer includes a second circuit 121 and a second circuit dielectric material 122, with the second circuit dielectric material 122 covering the second circuit 121. Furthermore, the second redistribution layer surface 125 is further provided with a plurality of solder resist pads 127.

[0039] The second line metal layer 123 is electrically connected to the second circuit 121, and the second line metal layer 123 is also electrically connected to the via metal layer 15. Specifically, the via metal layer 15 within each via 13 is electrically connected to the second line metal layer 123. A portion of the second line metal layer 123 is formed between the second line metal layer 123 and the core substrate layer 10, and is bonded to the second surface 12 of the core substrate layer 10, extending to connect to the via metal layer 15 in one of the vias 13.

[0040] The second line optical waveguide 124 and at least one of the reflectors 126 form the optical path in the second redistribution layer 120. The second line optical waveguide 124 is covered by the second line dielectric material 122, and the second line optical waveguide 124 is seamlessly connected to the through-hole optical waveguide 171 in each of the through-holes 13. A portion of the second line optical waveguide 124 is bonded to the second line metal layer 123 bonded to the core substrate layer 10.

[0041] In one embodiment, the second line metal layer 123 and the first line metal layer 113 are made of the same material, and the second line dielectric material 122 and the first line dielectric material 112 are made of the same material. The optical signal traveling in the second redistribution layer 120 is reflected into the second line optical waveguide 124 after contacting the heterogeneous second line dielectric material 122 and the second line metal layer 123. The via metal layer 15, the first line metal layer 113, and the second line metal layer 123 are all conductive.

[0042] Please see Figures 3A to 3J As shown, the core layer optical waveguide structure of this first embodiment is made by the following steps.

[0043] like Figure 3A As shown, a substrate is prepared to serve as the core substrate layer 10. The substrate may be a carrier board, and the substrate has opposing first surfaces 11 and second surfaces 12. Metal layers may already exist on the first surface 11 and the second surface 12.

[0044] like Figure 3BAs shown, at least one through-hole 13 is formed between the first surface 11 and the second surface 12 of the core substrate layer 10. The through-hole can be formed, for example, by laser drilling.

[0045] like Figure 3C As shown, a through-hole metal layer 15 is formed within each of the through holes 13, such that the through-hole metal layer 15 is formed on the inner wall surface 14 of each through hole 13, and a through-hole space 16 is also left in each through hole 13. For example, the through-hole metal layer 15 can be formed by performing a plated through hole (PTH) process. Preferably, when the through-hole metal layer 15 is formed within each of the through holes 13, a circuit metal layer is also formed on the first surface 11 and the second surface 12 of the core substrate layer 10. For example, an unpatterned first circuit metal layer 113 is electroplated on the first surface 11, and an unpatterned second circuit metal layer 123 is electroplated on the second surface 12.

[0046] like Figure 3D As shown, an unpatterned first circuit metal layer 113 and an unpatterned second circuit metal layer 123 are covered with an optical waveguide core material, and the via spaces 16 within each via 13 are filled. Thus, a via optical waveguide 171 is formed in the via spaces 16 of each via 13, and a prototype of a first circuit optical waveguide 114 is formed on the first surface 11 and a prototype of a second circuit optical waveguide 124 is formed on the second surface 12. In this step, the prototypes of the first circuit optical waveguide 114 and the second circuit optical waveguide 124 are seamlessly connected to the via optical waveguide 171 in the via spaces 16. Preferably, the optical waveguide core material can be a photosensitive material, such as a photoresist, and the via optical waveguide 171 is formed by filling the via spaces 16 with the photosensitive photoresist.

[0047] like Figure 3E As shown, a mold 400 forms at least one notch 20 in the prototype of the first line optical waveguide 114 and the prototype of the second line optical waveguide 124, respectively. Preferably, the first surface 11 and the second surface 12 are parallel, and the present invention can form at least one notch 20 by pressing with the mold 400, wherein the notch surface 21 formed at the notch 20 is set at a 45-degree angle relative to the first surface 11.

[0048] like Figure 3FAs shown, the core material of the optical waveguide on the first surface 11 and the second surface 12 is patterned using a photolithography process to pattern the prototypes of the first line optical waveguide 114 and the second line optical waveguide 124 on the first surface 11 and the second surface 12, respectively. In this embodiment, a portion of the patterned first line optical waveguide 114 is bonded to a portion of the first line metal layer 113, and a portion of the patterned second line optical waveguide 124 is bonded to a portion of the second line metal layer 123.

[0049] like Figure 3G and Figure 3H As shown, the photoresist used in the photolithography process is used to plan the areas for metal deposition, deposit the metal, and remove excess metal and photoresist to leave a patterned circuit. The patterned circuit includes a first circuit 111 formed on the first surface 11 and a second circuit 121 formed on the second surface 12. The first circuit 111 is electrically connected to the first line metal layer 113, and the second circuit 121 is electrically connected to the second line metal layer 123 (cross-sectional view is not shown).

[0050] like Figure 3I As shown, reflectors 116 and 126 are disposed on the aforementioned notch surface 21. Thus, the light signal can be reflected by the reflectors 116 and 126 at an incident angle and a reflection angle of 45 degrees, facilitating a 90-degree deflection of the light signal in its directional direction. Preferably, the reflectors 116 and 126 are curved metal surfaces.

[0051] like Figure 3J As shown, a dielectric material is laminated, for example, a first line dielectric 112 is formed on the first surface 11 to cover the first line metal layer 113 and the first line optical waveguide 114 that are in direct contact with each other, and a second line dielectric 122 is formed on the second surface 12 to cover the second line metal layer 123 and the second line optical waveguide 124 that are in direct contact with each other. Furthermore, portions of the first line optical waveguide 114 are exposed from the first line dielectric 112 and portions of the second line optical waveguide 124 are exposed from the second line dielectric 122 through a photolithography process.

[0052] Finally, this invention can achieve the desired effect through a series of semi-additive processes (SAP). Figure 3J Based on the structure shown, multiple layers of optical paths and circuits are stacked to form... Figure 2 The substrate structure of the first embodiment is shown. The technical content of this part utilizes SAP technology. However, since SAP technology is already used in the industry, the detailed steps of using SAP stack redistribution layers will not be described here.

[0053] Please see Figure 4 and Figures 5A to 5H As shown, Figure 4 This is a cross-sectional schematic diagram of the core layer optical waveguide structure of the present invention in a second embodiment, and this is as follows. Figure 4 The core layer optical waveguide structure of the second embodiment shown is composed of, for example, Figures 5A to 5H The process was completed using the method shown in the flowchart.

[0054] Please see Figure 4 In this second embodiment, the substrate structure of the present invention further provides the first redistribution layer 110 on the first surface 11 of the core substrate layer 10 and the second redistribution layer 120 on the second surface 12.

[0055] The first redistribution layer 110 includes a first line dielectric layer, a first line metal layer 113, a first line optical waveguide 114, a first redistribution layer surface 115 facing away from the core substrate layer 10, and at least one reflector 116. The first line dielectric layer includes a first circuit 111 and a first line dielectric material 112, with the first line dielectric material 112 covering the first circuit 111. The first redistribution layer surface 115 is provided with multiple circuit board components 128 for receiving or outputting electrical signals.

[0056] One of the circuit board components 128 is electrically connected to the first circuit 111 disposed in the first line dielectric material 112 via its corresponding contact. One of the circuit board components 128 is electrically connected to the first line metal layer 113 via the first circuit 111, and further electrically connected to the via metal layer 15 via the first line metal layer 113. In detail, the core substrate layer 10 has a plurality of vias 13, and the via metal layer 15 in each via 13 is electrically connected to the first line metal layer 113. A portion of the first line metal layer 113 is formed between the first line dielectric material 112 and the core substrate layer 10, and is attached to the first surface 11 of the core substrate layer 10, and extends to connect to the via metal layer in at least one via 13.

[0057] The first line waveguide 114 and at least one reflector 116 form the optical path in the first redistribution layer 110. The first line waveguide 114 is covered by the first line dielectric material 112, and the first line waveguide 114 is seamlessly connected to one of the circuit board components 128 and the via waveguide 171 in at least one via 13. The first line waveguide 114 is used to transmit the optical signal generated by an optical signal generating element (not shown in the figure). The via waveguide 171 in each via 13 is perpendicular to the first surface 11, and through the arrangement of the reflector 116 in the first line waveguide 114, the optical signal transmitted by the first line waveguide 114 and the via waveguide 171 can bend by 90 degrees, changing from perpendicular to the first surface 11 to parallel to the first surface 11. Preferably, the reflector 116 is arranged at a 45-degree angle relative to the first surface 11. Regardless of whether the optical signal is reflected between the dielectric material 112 of the first line or between the metal layer 113 of the first line, the optical signal can still travel stably in the optical waveguide 114 of the first line.

[0058] The second redistribution layer 120 includes a second line dielectric layer, a second circuit 121, a second line dielectric material 122, a second line metal layer 123, a second line optical waveguide 124, a second redistribution layer surface 125 facing away from the core substrate layer 10, and at least one reflector 126. The second line dielectric layer includes the second circuit 121 and the second line dielectric material 122, with the second line dielectric material 122 covering the second circuit 121. The second redistribution layer surface 125 further provides another circuit board element 128 for mounting the substrate structure described in this invention.

[0059] The second line metal layer 123 is electrically connected to the second circuit 121, and the second line metal layer 123 is also electrically connected to the via metal layer 15. Thus, the via metal layer 15 within each via 13 is electrically connected to the second line metal layer 123. A portion of the second line metal layer 123 is formed between the second line metal layer 123 and the core substrate layer 10, and is bonded to the second surface 12 of the core substrate layer 10, extending and connecting to the via metal layer 15 in at least one via 13.

[0060] The second line optical waveguide 124 and at least one of the reflectors 126 form the optical path in the second redistribution layer 120. The second line optical waveguide 124 is formed in the second line dielectric material 122 and is seamlessly connected to the via optical waveguide 171 in at least one via 13. The second line optical waveguide 124 is used to transmit the optical signal received by an optical signal receiving element (not shown in the figure). Furthermore, the second line metal layer 123 and the first line metal layer 113 are made of the same material, and the second line dielectric material 122 and the first line dielectric material 112 are made of the same material.

[0061] like Figure 4 As shown in region 101, in this second embodiment, the through-hole optical waveguide 171 provided in a portion of the through-hole 13 is not connected to the first line optical waveguide 114 or the second line optical waveguide 124. This means that the through-hole optical waveguide 171 not connected to the first line optical waveguide 114 or the second line optical waveguide 124 is not functionally used for transmitting the optical signal, but rather for filling the through-hole 13. In other words, conventionally, the through-hole 13 is filled with a via-filling ink, however, the present invention can directly utilize the through-hole optical waveguide 171 formed in the through-hole 13 to replace the function of the via-filling ink. In terms of manufacturing process, this approach is more efficient, eliminating the need for additional via-filling ink injection and saving the cost of the via-filling ink. The through-hole optical waveguide 171 is non-conductive, therefore it can functionally replace the via-filling ink. When one of the vias 13 not used as an optical path needs to be converted into part of an optical path, the present invention does not require removing the filler material in the via 13, nor does it require any modification to the via 13 already filled with the via optical waveguide 171. Therefore, replacing the via-filling ink with the via optical waveguide 171 fully provides the practical advantages of this invention.

[0062] Please see Figures 5A to 5H As shown, the core layer optical waveguide structure of this second embodiment is made by the following steps.

[0063] like Figure 5A As shown, the substrate is prepared to serve as the core substrate layer 10. The substrate has a first surface 11 and a second surface 12 facing each other, and metal layers may be present on the first surface 11 and the second surface 12 respectively.

[0064] like Figure 5B As shown, at least one through-hole 13 is formed between the first surface 11 and the second surface 12 of the core substrate layer 10. The through-hole can be formed, for example, by laser drilling.

[0065] like Figure 5CAs shown, a through-hole metal layer 15 is formed within each of the through holes 13, such that the through-hole metal layer 15 is formed on the inner wall surface 14 of each through hole 13, and a through-hole space 16 is also left in each through hole 13. For example, the through-hole metal layer 15 is formed by performing the electroplating through-hole method. Preferably, when the through-hole metal layer 15 is formed within each of the through holes 13, a first circuit metal layer 113 that has not yet been patterned is electroplated on the first surface 11, and a second circuit metal layer 123 that has not yet been patterned is electroplated on the second surface 12.

[0066] like Figure 5D As shown, a through-hole optical waveguide 171 is formed in the through-hole space 16 of each of the through-holes 13. For example, an optical waveguide core material is injected into the through-hole space 16 of each of the through-holes 13 to fill the through-hole space 16 of each of the through-holes 13 with the optical waveguide core material. Preferably, the optical waveguide core material can be a photosensitive material, such as a photoresist, and the through-hole optical waveguide 171 is formed by filling the through-hole space 16 with the photosensitive photoresist.

[0067] like Figure 5E As shown, the first line metal layer 113 on the first surface 11 and the second line metal layer 123 on the second surface 12 are respectively patterned by a photolithography process.

[0068] like Figure 5F As shown, a dielectric material is used to cover the via optical waveguide, the first line metal layer 113 on the first surface 11, and the second line metal layer 123 on the second surface 12, and the dielectric material is patterned using another photolithography process. For example, a first line dielectric 112 is formed on the first surface 11 but the first line metal layer 113 is exposed, a second line dielectric 122 is formed on the second surface 12 but the second line metal layer 123 is exposed, and the first line dielectric 112 and the second line dielectric 122 expose the via optical waveguide 171 in at least one via 13.

[0069] like Figure 5G As shown, metal is deposited on the first surface 11 and the second surface 12, and the deposited metal is patterned by another photolithography process to form a first circuit 111 electrically connected to the first line metal layer 113 on the first surface 11, and a second circuit 121 electrically connected to the second line metal layer 123 on the second surface 12, but the via optical waveguide 171 in at least one via 13 is exposed.

[0070] like Figure 5HAs shown, the exposed through-hole waveguide 171 is covered with the core material of the waveguide, and the core material of the waveguide is patterned by another photolithography process to form a line waveguide that is seamlessly connected to the through-hole waveguide 171 in the through-hole space 16, that is, the first line waveguide 114 and the second line waveguide 124 that are seamlessly connected to the through-hole waveguide 171.

[0071] Next, through a series of steps, including: respectively laminating another dielectric material to cover the first line optical waveguide 114 and the second line optical waveguide 124, patterning the dielectric material, laminating the optical waveguide core material, molding the optical waveguide core material to form at least one notch 20, patterning the optical waveguide core material, placing the reflector on the notch surface 21 of the at least one notch 20, laminating another dielectric material again, and then stacking the redistribution layer through SAP, a process is formed. Figure 4 The substrate structure of the second embodiment shown.

[0072] Please see Figure 6 As shown, Figure 6 This is a schematic diagram showing a cross-section of the through-hole optical waveguide 171 in the core substrate layer 10 of the second embodiment, parallel to the first surface 11. As can be seen, the through-hole metal layer 15 surrounds and covers the through-hole optical waveguide 171. Preferably, the through-hole optical waveguide 171 and the through-hole metal layer 15 are arranged as follows: Figure 6 The concentric circles shown are illustrated, and the via waveguide 171 has a via waveguide diameter D1, while the via metal layer 15 has a via metal layer diameter D2. The ratio of the via waveguide diameter D1 to the via metal layer diameter D2 can be between 1:1.2 and 1:26. For example, the via metal layer diameter D2 can have an inner diameter and an outer diameter, the inner diameter of the via metal layer diameter D2 can have the aforementioned ratio of 1:1.2, and the outer diameter of the via metal layer diameter D2 can have the aforementioned ratio of 1:26. Preferably, the via waveguide diameter D1 of the via waveguide 171 can be between 5 micrometers (μm) and 100 micrometers (μm).

[0073] Please see Figure 7 and Figures 8A to 8G As shown, Figure 7 This is a cross-sectional schematic diagram of the core layer optical waveguide structure of the present invention in a third embodiment, and this is as follows. Figure 7 The core layer optical waveguide structure of the third embodiment shown is composed of, for example, Figures 8A to 8G The process was completed using the method shown in the flowchart.

[0074] Please see Figure 7In this third embodiment, the substrate structure of the present invention further provides the first redistribution layer 110 on the first surface 11 of the core substrate layer 10 and the second redistribution layer 120 on the second surface 12.

[0075] The first redistribution layer 110 includes a first line dielectric layer, a first line metal layer 113, a first line optical waveguide 114, a first redistribution layer surface 115 facing away from the core substrate layer 10, and at least one reflector 116. The first redistribution layer surface 115 is provided with a circuit board element 128 for receiving or outputting the electrical signal. The first line dielectric layer includes a first circuit 111 and a first line dielectric material 112, with the first line dielectric material 112 covering the first circuit 111.

[0076] The circuit board element 128 is electrically connected to the first circuit 111 via its corresponding contact. The circuit board element 128 is electrically connected to the first line metal layer 113 via the first circuit 111, and further electrically connected to the via metal layer 15 via the first line metal layer 113. Specifically, the core substrate layer 10 has at least one via 13 and at least one general via 18, and the via metal layer 15 within the at least one via 13 is electrically connected to the first line metal layer 113. A portion of the first line metal layer 113 is formed between the first line dielectric material 112 and the core substrate layer 10, and is bonded to the first surface 11 of the core substrate layer 10, extending and connecting to the via metal layer 15 within the at least one via 13.

[0077] In this embodiment, the optical waveguide unit 17, in addition to the through-hole optical waveguide 171, further includes a dielectric cladding layer 172. The dielectric cladding layer 172 covers the through-hole optical waveguide 171, and the dielectric cladding layer 172 and the through-hole optical waveguide 171 are formed together in the through-hole space 16 of the through-hole 13, such that the through-hole optical waveguide 171 and the through-hole metal layer 15 are separated by the dielectric cladding layer 172. The through-hole optical waveguide 171 of the present invention has an optical waveguide refractive index, while the dielectric cladding layer 172 has a cladding layer refractive index. To ensure the practicality of the optical signal transmission, this embodiment limits the optical waveguide refractive index of the through-hole optical waveguide 171 to be greater than the cladding layer refractive index of the dielectric cladding layer 172. Thus, the optical signal traveling through the via 13 touches the dielectric coating layer 172 and is reflected into the via optical waveguide 171. Additionally, the wall of at least one of the general vias 18 is also formed with a via metal layer 15; however, the via metal layer 15 only covers the dielectric coating layer 172 within the at least one general via 18. In other words, at least one general via 18 can only be used to transmit electrical signals, and cannot transmit optical signals. The significance of this arrangement is that for at least one general via 18 not used to transmit optical signals, it is not necessary to use via-sealing ink in the manufacturing process; instead, it can be efficiently and cost-effectively sealed directly in the manufacturing process using the formation of the dielectric coating layer 172.

[0078] The first line optical waveguide 114 and at least one reflector 116 form the optical path in the first redistribution layer 110. The first line optical waveguide 114 is formed in the first line dielectric material 112 and is seamlessly connected to the via optical waveguide 171 in at least one via 13. The first line optical waveguide 114 is used to transmit the optical signal. The via optical waveguide 171 in each via 13 is perpendicular to the first surface 11, and through the arrangement of the reflector 116 in the first line optical waveguide 114, the optical signal transmitted by the first line optical waveguide 114 and the via optical waveguide 171 can be turned by 90 degrees, changing from perpendicular to the first surface 11 to a path parallel to the first surface 11. Preferably, the reflector 116 is arranged at a 45-degree angle relative to the first surface 11.

[0079] In this embodiment, the dielectric cladding layer 172 and the first line dielectric material 112 are made of the same material, and the first line dielectric material 112 has the refractive index of the dielectric layer. In other words, the refractive index of the cladding layer is equal to the refractive index of the dielectric layer, and the refractive index of the optical waveguide is greater than both the refractive index of the cladding layer and the refractive index of the dielectric layer.

[0080] The second redistribution layer 120 includes a second line dielectric layer, a second line metal layer 123, a second line optical waveguide 124, a second redistribution layer surface 125 facing away from the core substrate layer 10, and at least one reflector 126. The second line dielectric layer includes a second circuit 121 and a second line dielectric material 122, with the second line dielectric material 122 covering the second circuit 121. The second redistribution layer surface 125 further provides circuit board elements 128 for carrying the substrate structure of the present invention. The second line metal layer 123 is electrically connected to the second circuit 121 and to the via metal layer 15. Thus, the via metal layer 15 within each via 13 is electrically connected to the second line metal layer 123. A portion of the second line metal layer 123 is formed between the second line metal layer 123 and the core substrate layer 10, and is bonded to the second surface 12 of the core substrate layer 10, and extends to connect to the through-hole metal layer 15 in at least one of the through holes 13.

[0081] The second line optical waveguide 124 and at least one of the reflectors 126 form the optical path in the second redistribution layer 120. The second line optical waveguide 124 is covered by the second line dielectric material 122, and the second line optical waveguide 124 is seamlessly connected to the via optical waveguide 171 within at least one via 13. The second line optical waveguide 124 is used to transmit the optical signal. Furthermore, the second line dielectric material 122 and the first line dielectric material 112 are made of the same material.

[0082] Please see Figures 8A to 8G As shown, the core layer optical waveguide structure of this third embodiment is made by the following steps.

[0083] like Figure 8A As shown, the substrate is prepared to serve as the core substrate layer 10. The substrate has a first surface 11 and a second surface 12 facing each other, and metal layers may be present on the first surface 11 and the second surface 12 respectively.

[0084] like Figure 8B As shown, at least one through-hole 13 and at least one general through-hole 18 are formed between the first surface 11 and the second surface 12 of the core substrate layer 10. The penetration of the core substrate layer 10 can be achieved, for example, by laser drilling, and the diameters of the at least one through-hole 13 and the at least one general through-hole 18 can be different.

[0085] like Figure 8CAs shown, a through-hole metal layer 15 is formed within each of the through holes 13, such that the through-hole metal layer 15 is formed on the inner wall surface 14 of each through hole 13, and a through-hole space 16 is also left in each through hole 13. For example, the through-hole metal layer 15 is formed by performing the through-hole electroplating method. Preferably, when the through-hole metal layer 15 is formed within each of the through holes 13, an unpatterned first circuit metal layer 113 is electroplated on the first surface 11, and an unpatterned second circuit metal layer 123 is electroplated on the second surface 12. Then, a photolithography process is used to pattern the unpatterned first circuit metal layer 113 into the first circuit metal layer 113 and the unpatterned second circuit metal layer 123 into the second circuit metal layer 123.

[0086] like Figure 8D As shown, the first surface 11, the second surface 12, at least one through hole 13, and at least one general through hole 18 are completely covered by dielectric material.

[0087] like Figure 8E As shown, through exposure and development in another lithography process, the dielectric material is partially hollowed out in the through-hole 13, and the first circuit metal layer 113 and the second circuit metal layer 123 are exposed. Thus, a dielectric coating layer 172 is formed on the inner wall surface 14 in the through-hole 13.

[0088] like Figure 8F As shown, metal is deposited on the first surface 11 and the second surface 12, and the deposited metal is patterned by another photolithography process to form a first circuit 111 electrically connected to the first line metal layer 113 on the first surface 11, and a second circuit 121 electrically connected to the second line metal layer 123 on the second surface 12, but at least one via space 16 in the via 13 is exposed.

[0089] like Figure 8G As shown, the first line metal layer 113 and the second line metal layer 123 are covered with an optical waveguide core material, and the via 13 is filled. The optical waveguide core material is then patterned using another photolithography process. Thus, a via optical waveguide 171 covered by the dielectric coating layer 172 is formed in the via space 16 within the via 13, and a line optical waveguide seamlessly connected to the via optical waveguide 171 in the via space 16 is formed, namely, the first line optical waveguide 114 and the second line optical waveguide 124 seamlessly connected to the via optical waveguide 171.

[0090] Next, through a series of steps, including: molding the optical waveguide core material to form at least one notch 20; setting the reflector 116 and reflector 126 on the notch surface 21 of the at least one notch 20; laminating another layer of dielectric material to cover the first line optical waveguide 114 and the second line optical waveguide 124 respectively; patterning the dielectric material to expose the first circuit 111 and the second circuit 121; depositing metal and further extending the first circuit 111 and the second circuit 121 through another lithography process; and finally stacking the redistribution layer through SAP, the waveguide is formed. Figure 7 The substrate structure of the third embodiment shown.

[0091] like Figure 9A and Figure 9B As shown, Figure 9A This is a schematic diagram showing a cross-section of one of the through-holes 13 in the core substrate layer 10 of the third embodiment, parallel to the first surface 11. Figure 9B This is a schematic diagram showing a cross-section of one of the general vias 18 in the core substrate layer 10 of the third embodiment, parallel to the first surface 11. Preferably, in the via 13, the via optical waveguide 171, the dielectric cladding layer 172, and the via metal layer 15 are arranged as follows: Figure 9A The concentric circles shown. In this general through-hole 18, the dielectric coating layer 172 and the through-hole metal layer 15 are arranged as follows. Figure 9B The concentric circles shown.

[0092] like Figure 9A As shown, the through-hole waveguide 171 has a through-hole waveguide diameter D1, the through-hole metal layer 15 has a through-hole metal layer diameter D2, and the dielectric cladding layer 172 has a dielectric layer diameter D3. The ratio of the through-hole waveguide diameter D1 to the dielectric layer diameter D3 to the through-hole metal layer diameter D2 can be a value between 1:1.1:1.5 and 1:50:100.

[0093] For example, the dielectric layer diameter D3 may have an inner diameter and an outer diameter. The inner diameter of the dielectric layer D3 may have the aforementioned ratio of 1:1.1, and the outer diameter of the dielectric layer D3 may have the aforementioned ratio of 1:50. The via metal layer diameter D2 may have an inner diameter and an outer diameter. The inner diameter of the via metal layer D2 may have the aforementioned ratio of 1:1.5, and the outer diameter of the via metal layer D2 may have the aforementioned ratio of 1:100. Preferably, the via optical waveguide 171 has a via optical waveguide diameter D1 that is between 5 micrometers (μm) and 100 micrometers (μm).

[0094] In summary, it can be seen that the manufacturing method of the present invention, regardless of the embodiment, can be summarized into the following steps for producing a substrate structure with optical waveguides within through-holes:

[0095] The through-hole 13 is formed by penetrating the first surface 11 and the second surface 12 of the core substrate layer 10 to connect the opposing first surface 11 and second surface 12.

[0096] The through-hole metal layer 15 is formed on the inner wall surface 14 of the through-hole 13, and the through-hole space 16 connecting the first surface 11 and the second surface 12 is left in the through-hole 13.

[0097] The optical waveguide unit 17 is formed in the through-hole space 16 of the through-hole 13. In some embodiments, the optical waveguide unit 17 only has the through-hole optical waveguide 171. In some embodiments, the optical waveguide unit 17 further has the dielectric cladding layer 172.

[0098] The substrate structure of this invention improves upon the structure of existing optoelectronic hybrid boards. Specifically, this substrate structure allows for the simultaneous transmission of optical and electrical signals through the vias 13 of the core substrate layer 10 via the via optical waveguide 171 and the via metal layer 15, significantly saving substrate wiring space. Furthermore, the manufacturing method of this invention, besides efficiently producing the substrate structure, can also fill unused vias on the substrate structure with dielectric or optical guide materials, eliminating the need for additional via-filling ink and saving costs. Vias sealed with optical guide materials can also serve as backup optical paths for transmitting optical signals. In other words, when readjusting the optical path, vias sealed with optical guide materials can more efficiently integrate the first line optical waveguide 114 on the first surface 11 and the second line optical waveguide 124 on the second surface 12 during the manufacturing process, making it easier to initiate optical signal transmission after modifications.

[0099] The above are merely illustrative embodiments of the present invention and are not intended to limit the scope of the invention. Any equivalent changes and modifications made by those skilled in the art without departing from the concept and principles of the present invention should fall within the scope of protection of the present invention.

Claims

1. A substrate structure with an optical waveguide within a through-hole, characterized in that, include: A core substrate layer having a first surface and a second surface opposite to each other; A through hole penetrates the core substrate layer to connect the first surface and the second surface, and the through hole has an inner wall surface; A through-hole metal layer is formed on the inner wall surface of the through-hole, and the through-hole metal layer leaves a through-hole space in the through-hole connecting the first surface and the second surface; An optical waveguide unit is formed in the through-hole space of the through-hole, and the optical waveguide unit has a through-hole optical waveguide.

2. The substrate structure as described in claim 1, characterized in that, The through-hole optical waveguide is in direct contact with the through-hole metal layer.

3. The substrate structure as described in claim 2, characterized in that, The substrate structure also includes: A line metal layer is formed on the first surface of the core substrate layer. The line metal layer is conductive and is connected to the via metal layer. A dielectric layer for the circuit is formed on the metal layer of the circuit; A line optical waveguide is formed in the line dielectric layer, and the line optical waveguide is seamlessly connected to the via optical waveguide; In this circuit, the optical waveguide is in direct contact with the metal layer of the circuit.

4. The substrate structure as described in claim 1, characterized in that, The optical waveguide unit also has a dielectric cladding layer; The dielectric cladding layer covers the through-hole optical waveguide and is formed together with the through-hole optical waveguide in the through-hole space, such that the through-hole optical waveguide and the through-hole metal layer are separated by the dielectric cladding layer, and the dielectric cladding layer has a cladding layer refractive index. The through-hole optical waveguide has a waveguide refractive index, and the waveguide refractive index is greater than the cladding layer refractive index.

5. The substrate structure as described in claim 4, characterized in that, The substrate structure also includes: A line metal layer is formed on the first surface of the core substrate layer. The line metal layer is conductive and is connected to the via metal layer. A dielectric layer for the circuit is formed on the metal layer of the circuit; A line optical waveguide is formed in the line dielectric layer, and the line optical waveguide is seamlessly connected to the via optical waveguide; The optical waveguide and the metal layer of the line are spaced apart.

6. The substrate structure as described in claim 5, characterized in that, The dielectric layer of the circuit has a dielectric layer refractive index, and the optical waveguide of the circuit has the optical waveguide refractive index. The refractive index of the optical waveguide is greater than that of the dielectric layer.

7. The substrate structure as described in claim 3 or 5, characterized in that, The substrate structure also includes: A reflector is placed in the optical waveguide of the line.

8. The substrate structure as described in claim 3 or 5, characterized in that, The substrate structure also includes: An electronic component is disposed on the dielectric layer of the circuit; wherein the dielectric layer of the circuit has a circuit and a dielectric material, the circuit is electrically connected to the electronic component, and the through-hole metal layer transmits an electrical signal between the circuit and the electronic component, and the dielectric material covers the circuit. An optoelectronic element is disposed on the dielectric layer of the circuit; wherein the circuit optical waveguide connects the optoelectronic element, and the through-hole optical waveguide transmits an optical signal between the optoelectronic element and the circuit optical waveguide.

9. A method for fabricating a substrate structure with an optical waveguide within a through-hole, characterized in that, Includes the following steps: A through-hole is formed by penetrating a first surface and a second surface of a core substrate layer to connect the opposing first surface and the second surface. A through-hole metal layer is formed on one inner wall surface of the through hole, and a through-hole space connecting the first surface and the second surface is left in the through hole; An optical waveguide unit is formed in the through-hole space of the through-hole; wherein the optical waveguide unit has a through-hole optical waveguide.

10. The manufacturing method as described in claim 9, characterized in that, When the through-hole metal layer is formed on the inner wall surface of the through-hole, a conductive line metal layer is also formed on the first surface and the second surface of the core substrate layer.

11. The manufacturing method as described in claim 10, characterized in that, The step of forming the optical waveguide unit in the via space of the via specifically includes the following sub-steps: The circuit metal layer on the first surface is covered with an optical waveguide core material, the circuit metal layer on the second surface is covered with an optical waveguide core material, and the through-hole space is filled. The optical waveguide core material on the first surface and the second surface is patterned by a photolithography process to form a line optical waveguide on the first surface and the second surface, which is seamlessly connected to the through-hole optical waveguide formed in the through-hole space; wherein, one of the line optical waveguides on the first surface or the second surface directly contacts the line metal layer. The circuit's metal layer and optical waveguide are coated with a dielectric material.

12. The manufacturing method as described in claim 10, characterized in that, The step of forming the optical waveguide unit in the via space of the via specifically includes the following sub-steps: A core material of an optical waveguide is filled into the through-hole space to form the through-hole optical waveguide in the through-hole space; The circuit metal layer on the first surface and the second surface is patterned using a photolithography process, respectively. The through-hole optical waveguide, the line metal layer on the first surface and the second surface are coated with a dielectric material, and the dielectric material is patterned by another photolithography process to expose the through-hole optical waveguide. The exposed via optical waveguide is covered with an optical waveguide core material, and the optical waveguide core material is patterned by another photolithography process to form a line optical waveguide that is seamlessly connected to the via optical waveguide in the via space. The optical waveguide of the circuit is covered with another layer of the same dielectric material.

13. The manufacturing method as described in claim 10, characterized in that, The step of forming the optical waveguide unit in the via space of the via further includes the following sub-steps: The circuit metal layer on the first surface and the second surface is patterned using a photolithography process, respectively. The circuit metal layer on the first surface and the second surface is covered with a dielectric material, and the via space in the via is filled. A dielectric coating layer is formed on the inner wall surface of the through hole by a second photolithography process that penetrates part of the dielectric material in the through hole. A core material of an optical waveguide is used to cover the circuit metal layer on the first surface, the circuit metal layer on the second surface, and fill the via, so as to form the via optical waveguide covered by the dielectric coating layer in the via space of the via. The optical waveguide core material on the first surface and the second surface is patterned by another photolithography process to form a line optical waveguide on the first surface and the second surface that is seamlessly connected to the through-hole optical waveguide in the through-hole space. The optical waveguide on the first surface and the optical waveguide on the second surface are respectively covered with another layer of the dielectric material.

14. The manufacturing method according to any one of claims 11 to 13, characterized in that, Before the optical waveguide of the line is covered by the dielectric material, the following steps are also included: A notch is formed in the optical waveguide of the circuit using a mold; wherein a notch surface is formed at the notch, and the notch surface has a 45-degree angle with the first surface of the core substrate layer; A reflector is placed on the surface of the notch.

Images