TWI393509B - Optoelectric hybrid circuit board and manufacture thereof - Google Patents

Description

Photoelectric hybrid circuit board and manufacturing method thereof

The present invention relates to an opto-electric hybrid circuit board and a method of manufacturing the same, and more particularly to an opto-electric hybrid circuit board in which a microlens is fabricated in an optical waveguide structure and a method of fabricating the same.

With the rapid development of communication systems and Very Large Scale Integration (VLSI) technology, the speed of communication and computer equipment has increased dramatically. Nowadays, there is an increasing demand for high-speed signal transmission between computers. The way in which copper wires are used to transmit electronic signals is limited by the lack of bandwidth, and it is impossible to load such a large transmission signal, and the copper wires are subjected to high-speed transmission. During the process, electromagnetic interference, reduced transmission reliability, and difficulty in heat dissipation will occur.

In order to improve this problem, in recent years, the technology of developing an opto-electric hybrid circuit has been developed, and an optical waveguide component is combined with an optical transceiver component to replace a conventional metal wire as a medium for transmitting an electronic signal. Due to its high parallelism, high frequency bandwidth, and extremely low Electromagnetic Interference (EMI), optical transmission is ideal for signal transmission applications between boards or wafers.

Since the optical waveguide component and the optical transceiver component must be coupled to optical alignment, and the current opto-electric hybrid circuit is increasingly miniaturized, it is quite unnecessary to design optical path bending, concentrating, and optical switching optical path wiring in a limited space. Easy.

In view of the above, U.S. Patent No. 6,599,031 discloses an optoelectronic transmission package module in which a transparent polymer layer is disposed on a photovoltaic substrate, and an optical transceiver component is disposed on one side of the transparent polymer layer in the polymer layer and the photoelectric layer. A plurality of microlens arrays are respectively fabricated on opposite sides of the substrate to refract optical signals into the optical fibers.

In the above patents, before the microlens is manufactured, the polymer layer must be polished, and the lens system is separately fabricated on the polymer layer and the photoelectric substrate, so that the lens is not easily integrated with the photovoltaic substrate process, and the manufacturing is also caused. Increase in processes and costs. Moreover, the distance between the lens and the optical waveguide component is too far, and the error caused by the manufacturing of the lens component causes the light beam projected into the lens to be offset, thereby being misaligned with the turning component in the optical waveguide optical path. This leads to poor optical coupling efficiency.

An optical circuit board having a vertical optical waveguide component and a horizontal optical waveguide component and a microlens disposed at a starting point of the optical path of the vertical optical waveguide, the optical signal projected by the light source is passed through the patent application No. 6,804,423. The lens is focused, and the focused optical signal passes through the vertical optical waveguide, and is further reflected in the optical waveguide optical path by the folding mirror disposed at the boundary between the vertical optical waveguide and the horizontal optical waveguide.

In the case of Patent No. 6,804,423, the relative distance between the lens and the turning mirror surface is too far, and the focused optical signal still has a problem of divergence, which makes it impossible to project all the light energy into the turning mirror surface for total reflection. In addition, the turning mirror surface is separately manufactured by diamond cutting or laser cutting after the optical waveguide component is completed, which will result in an excessively complicated manufacturing process of the optical circuit board and an increase in manufacturing cost.

In view of the above problems, the present invention provides an opto-electric hybrid circuit board and a method of fabricating the same, which improves the prior art opto-electric hybrid circuit, wherein the arrangement distance of the microlens for refracting the optical signal is too long, so that the refracted optical signal is easily generated. Divergence and offset, and the conventional microlens is independently fabricated on the optoelectronic substrate, and the microlens is not easily integrated with the optoelectronic substrate, resulting in poor optical coupling efficiency, complicated process, and high cost.

The opto-electric hybrid circuit board disclosed in the present invention is for receiving and transmitting an optical signal, which comprises a conductive substrate and an optical waveguide structure. The optical waveguide structure has a first cladding layer, a core layer, and a second cladding layer sequentially stacked on the conductive substrate to form an optical transmission path through which the optical signal passes, and formed on the first cladding layer. There is at least one microlens disposed on the light transmission path to refract the optical signal passing through the microlens.

In the method for manufacturing an opto-electric hybrid circuit board of the present invention, first, a conductive substrate is provided, a first cladding layer is formed on one side of the conductive substrate, and at least one microlens is formed on the first cladding side, and the microlens corresponds to In the light transmission direction of the optical signal, the optical signal is refracted. Then, a core layer is formed on the first cladding layer, and finally a second cladding layer is formed on the core layer to form an optical transmission path.

The opto-electric hybrid circuit of the present invention and the method of manufacturing the same have the following advantages: 1. The microlens is highly integrated with the optical transmission path.

2. Save the cost of separate production of individual components.

3. Simplify the process of the opto-electric hybrid circuit.

4. The optical signal has a short focusing distance and a high optical alignment tolerance.

5. Can be applied to three-dimensional (3D) multilayer optical path transmission.

The above description of the present invention and the following description of the embodiments of the present invention are intended to illustrate and explain the principles of the invention.

Fig. 1 is a schematic cross-sectional view showing the first embodiment. The opto-electric hybrid circuit board 100 of the present invention is used to receive and transmit an optical signal. The opto-electric hybrid circuit board 100 includes a conductive substrate 110 and an optical waveguide structure 120 disposed on the conductive substrate 110.

The conductive substrate 110 of the first embodiment is a printed circuit board having a metal conductive wiring on its surface, for example, a conductive substrate 110 of a non-transparent material such as a resin copper foil substrate (FR4 substrate or BT substrate). The conductive substrate 110 defines a plurality of light guiding holes 111, and a light guiding core layer 112 is disposed in the light guiding hole 111, and a light guiding coating layer 113 surrounding the light guiding core layer 112.

The conductive substrate 110 is electrically connected to a light emitter 151 corresponding to one of the light guiding holes 111 and a light receiver 152 corresponding to the other light guiding hole 111. The light emitter 151 can emit an optical signal through the opto-electric hybrid circuit board 100 and be received by the optical receiver 152.

The optical waveguide structure 120 has a first cladding layer 121 covering one side of the conductive substrate 110, a core layer 122 covering the first cladding layer 121, and a second cladding layer 123 covering the core layer 122. To form an optical transmission path 130. The optical transmission path 130 further has two guiding optical paths 131 corresponding to the optical transmitter 151 and the optical receiver 152, and a reflected optical path 132 connected to the guiding optical path 131 to receive the optical signal emitted by the optical transmitter 151, and The optical signal is transmitted to the optical receiver 152 through the guiding optical path 131.

The refractive index of the first cladding layer 121 and the second cladding layer 123 are the same, and the refractive index of the core layer 122 sandwiched between the two cladding layers 121 and 123 is greater than the cladding layer. The refractive index of 121, 123, the core layer 122 of the present invention has a refractive index of 1.553, and the cladding layers 121 and 123 have a refractive index of 1.534, so that the optical signal is totally reflected in the core layer 122, and is transmitted according to the designed light. Path 130 travels.

The optical waveguide structure 120 further has at least one microlens 124 and at least one reflective surface 140. The microlens 124 is disposed on the optical transmission path 130 to cause the optical signal emitted by the optical transmitter 151 to be focused, leveled, or diverged. The reflective surface 140 is disposed at the position of the guiding optical path 131 and the reflected optical path 132. Up, and adjacent to the microlens 124.

The optical signal passing through the guiding optical path 131 of the present invention is focused on the reflecting surface 140 by the focusing action of the microlens 124, and the traveling direction of the focused optical signal is converted by the reflecting surface 140, and reflected into the reflected optical path 132. The total reflection is performed, and the optical signal is focused and received by the light receiver 152 via the reflective surface 140 and the microlens 124 at the other end of the reflected optical path 132.

The reflecting surface 140 is disposed at a position where the guiding light path 131 and the reflecting light path 132 are connected, and the reflecting surface 140 is inclined at an angle of 35 to 55 degrees with respect to the side of the first covering layer 121, and the present invention is inclined by 45 degrees. The corner reflecting surface 140 is described as an embodiment. The reflective surface 140 can be designed to match the optical path of the actual optical waveguide structure 120, and is inclined to an appropriate angle, and is not limited to the 45 degree angle disclosed in the embodiment. In addition, a metal plating film 141 may be plated on the reflective surface 140 to increase the refractive effect of the focused light signal.

The material of the optical waveguide structure 120 of the present invention may be selected from an organic polymer material, such as an epoxy resin, an acrylic resin, or a polyester resin; or an organic polymer is selected. A mixture with an inorganic polymer material, such as a siloxane, a PMMA, or a polycarbonate resin (PC). The optical waveguide structure 120 manufactured from the above polymer material has advantages such as high dimensional stability, easy processing, and adjustment of optical properties according to requirements.

As shown in FIG. 2A to FIG. 2H and FIG. 3, the opto-electric hybrid circuit board 100 of the first embodiment of the present invention can be formed by the following manufacturing method: first, providing a conductive The substrate 110 (step 200) is formed by mechanical drilling or laser drilling to form at least one light guiding hole 111 on the conductive substrate 110 (step 210), and a light guiding core is formed in the light guiding hole 111. Layer 112 and light guiding cladding layer 113. Next, a first cladding layer 121 is formed on one side of the conductive substrate 110 (step 220), and at least one microlens 124 corresponding to the shape of the mold is formed on the first cladding layer 121 (step 230), the microlens The 124 is disposed on the other side of the conductive substrate 110 relative to the conductive substrate 110 and corresponds to the light transmission direction of the optical signal to refract the optical signal passing through the microlens 124. Next, a core layer 122 is formed on the first cladding layer 121 (step 240), and at least one reflective surface 140 is formed on the core layer 122 (step 250), and a surface of the reflective surface 140 is selectively formed with a metal coating. 141 (step 251) to increase the refractive effect of the optical signal. Finally, a second cladding layer 123 is formed on the core layer 122 (step 260) to form the optical transmission path 130.

The first cladding layer 121, the core layer 122, and the second cladding layer 123 of the present invention are sequentially stacked in a thermal curing or photocuring manner, and the microlens 124 for focusing and turning the traveling direction of the optical signal is The reflecting surface 140 can be formed on the first cladding layer 121 and the core layer 122 by mechanical processing such as hot pressing of a mold, laser engraving, or diamond cutter cutting. In addition, the microlens 124 and the reflective surface 140 may be integrated with the processes of the first cladding layer 121 and the core layer 122, and formed simultaneously with the first cladding layer 12 and the core layer 122 in a photocurable manner.

The manner in which the microlenses 124 and the reflective surface 140 are formed is well known to those of ordinary skill in the art. In addition to the practice of the present disclosure, a variety of processing methods can be used to form the microlenses 124 and the reflective surface 140. The inventor does not elaborate here.

Fig. 4 is a schematic cross-sectional view showing a second embodiment of the present invention. The conductive substrate 110 used in the opto-electric hybrid circuit board 100 of the second embodiment of the present invention may be a transparent printed circuit board, such as a glass substrate. The light emitter 151 and the light receiver 152 of the present invention correspond to the guide. The position of the optical path 131 does not need to drill a plurality of light guiding holes through which the optical signals pass through the conductive substrate 110.

Referring to FIG. 5, the present invention can sequentially stack a plurality of opto-electric hybrid circuit boards 100 to form a composite opto-electric hybrid substrate 160. The composite opto-electric hybrid substrate 160 has a plurality of optical transmission paths, and can simultaneously transmit and receive multiple sets of optical transmission signals. In addition, a collimating lens 153 can be disposed on the optical path of the optical transmitter 151 and the optical receiver 152 to align the optical signal passing through the optical transmission path to prevent the optical signal from passing through the composite optical hybrid substrate 160. Long, causing problems such as scattering and offset of optical signals.

The microlens of the present invention is formed on the optical transmission path of the optical waveguide structure at the same time when manufacturing the optical waveguide structure, so that the process of the opto-electric hybrid circuit board is highly integrated, and the process is simplified and the cost of manufacturing each optical component is saved. The microlens and the reflecting surface are adjacent to each other, so that the focusing distance of the optical signal is short, the optical alignment tolerance is high, and the three-dimensional (3D) multilayer optical path transmission effect is achieved by stacking a plurality of opto-electric hybrid circuit boards.

Although the embodiments of the present invention are disclosed above, it is not intended to limit the present invention, and those skilled in the art, regardless of the spirit and scope of the present invention, the shapes, structures, and features described in the scope of the present application. And the spirit of the invention is subject to change. Therefore, the scope of patent protection of the present invention is subject to the scope of the patent application attached to the specification.

100. . . Photoelectric hybrid circuit board

110. . . Conductive substrate

111. . . Light guide hole

112. . . Light guiding core layer

113. . . Light guiding coating

120. . . Optical waveguide structure

121. . . First cladding

122. . . Core layer

123. . . Second coating

124. . . Microlens

130. . . Optical transmission path

131. . . Guide light path

132. . . Reflected light path

140. . . Reflective surface

141. . . Metal coating

151. . . Light emitter

152. . . Optical receiver

153. . . Collimating lens

160. . . Composite opto-electric hybrid substrate

Step 200. . . Providing a conductive substrate

Step 210. . . Forming at least one light guiding hole on the conductive substrate

Step 220. . . Forming a first cladding layer on one side of the conductive substrate

Step 230. . . Forming at least one microlens on the side of the first cladding layer

Step 240. . . Forming a core layer on the first cladding layer

Step 250. . . Forming at least one reflective surface on the optical transmission path of the core layer

Step 251. . . Forming a metal coating on the surface of the reflective surface

Step 260. . . Forming a second cladding layer on the core layer

1 is a schematic cross-sectional view of a first embodiment of the present invention; FIG. 2A is a schematic exploded view of a first embodiment of the present invention; FIG. 2B is a schematic exploded view of a first embodiment of the present invention; 2D is a schematic diagram of an exploded step of the first embodiment of the present invention; FIG. 2E is a schematic diagram of an exploded step of the first embodiment of the present invention; FIG. 2F is a first embodiment of the present invention; 2D is a schematic diagram of a decomposition step of the first embodiment of the present invention; FIG. 2H is a schematic diagram of a decomposition step of the first embodiment of the present invention; FIG. 3 is a flow chart of the steps of the first embodiment of the present invention; 4 is a schematic cross-sectional view showing a second embodiment of the present invention; and FIG. 5 is a schematic cross-sectional view showing a composite opto-electric hybrid substrate of the present invention.

100. . . Photoelectric hybrid circuit board

110. . . Conductive substrate

111. . . Light guide hole

112. . . Light guiding core layer

113. . . Light guiding coating

120. . . Optical waveguide structure

121. . . First cladding

122. . . Core layer

123. . . Second coating

124. . . Microlens

130. . . Optical transmission path

131. . . Guide light path

132. . . Reflected light path

140. . . Reflective surface

141. . . Metal coating

151. . . Light emitter

152. . . Optical receiver

Claims (24)

An opto-electric hybrid circuit board for receiving and transmitting an optical signal, comprising: a conductive substrate having at least one light guiding hole; and an optical waveguide structure disposed on the conductive substrate, having a first package a coating layer, a core layer, a second cladding layer, and at least one microlens, the first cladding layer covering a side of the conductive substrate, the core layer covering the first cladding layer, the first layer a cover layer is disposed on the core layer to form an optical transmission path for receiving and transmitting the optical signal. The microlens is disposed on the optical transmission path to refract the optical signal, and the optical transmission path is further Having a guiding light path and a reflecting light path connected to the guiding light path, the guiding light path corresponding to the light guiding hole of the conductive substrate, and at least one reflection at the position where the guiding light path and the reflected light path are connected Face to change the direction of light transmission of the optical signal. The opto-electric hybrid circuit board of claim 1, wherein the conductive substrate is a non-transparent conductive substrate, the light guiding hole is provided with a light guiding core layer and a light guiding core layer is surrounded by the light guiding core layer. Light guiding coating. The opto-electric hybrid circuit board of claim 1, wherein at least one reflective surface is disposed at a position where the guiding optical path and the reflected optical path meet to change a light transmission direction of the optical signal. The opto-electric hybrid circuit board of claim 1, wherein the reflective surface is inclined at an angle of 35 degrees to 55 degrees with respect to a side of the first cladding layer. The opto-electric hybrid circuit board of claim 4, wherein the reflecting surface is inclined at an angle of 45 degrees with respect to one side of the first cladding layer. The opto-electric hybrid circuit board of claim 1, wherein the reflective surface The surface is further provided with a metal coating for changing the light transmission direction of the optical signal. The opto-electric hybrid circuit board of claim 1, wherein the conductive substrate is a transparent conductive substrate. The opto-electric hybrid circuit board of claim 1, wherein the optical waveguide structure is made of an organic polymer material. The opto-electric hybrid circuit board of claim 8, wherein the organic polymer material is selected from the group consisting of epoxy resin, acrylic resin, and polyester resin. The opto-electric hybrid circuit board of claim 1, wherein the optical waveguide structure is made of a mixture of an organic polymer material and an inorganic polymer material. The opto-electric hybrid circuit board of claim 10, wherein the mixture is selected from the group consisting of a siloxane resin, an acryl, and a polycarbonate resin. A method for manufacturing an opto-electric hybrid circuit board, wherein the opto-electric hybrid circuit board is configured to receive and transmit an optical signal, the method of the manufacturing method comprising: providing a conductive substrate; forming at least one light guiding hole on the conductive substrate; Forming a first cladding layer on a side of the conductive substrate; forming at least one microlens on a side of the first cladding layer, the microlens corresponding to a light transmission direction of the optical signal to refract the optical signal Forming a core layer on the first cladding layer; forming a second cladding layer on the core layer to form an optical transmission path, the optical transmission path further has a guiding optical path, and an interface a light guiding path of the guiding light path, the guiding light path corresponding to the light guiding hole of the conductive substrate; Forming at least one reflective surface on the optical transmission path of the core layer to change a light transmission direction of the optical signal. The method for manufacturing an opto-electric hybrid circuit board according to claim 12, further comprising: forming a light guiding core layer in the light guiding hole, and guiding light shielding surrounding the light guiding core layer; Floor. The method for manufacturing an opto-electric hybrid circuit board according to claim 12, further comprising the step of forming a metal plating film on the surface of the reflecting surface. The method of manufacturing an opto-electric hybrid circuit board according to claim 12, wherein the reflecting surface is formed by hot pressing a mold on the core layer. The method of manufacturing an opto-electric hybrid circuit board according to claim 12, wherein the reflecting surface is formed on the core layer by photocuring. The method of manufacturing an opto-electric hybrid circuit board according to claim 12, wherein the reflecting surface is formed on the core layer by laser engraving. The method of manufacturing an opto-electric hybrid circuit board according to claim 12, wherein the reflecting surface is formed on the core layer by a diamond cutter cutting method. The method for manufacturing an opto-electric hybrid circuit board according to claim 12, wherein the first cladding layer, the core layer and the second cladding layer are formed by a heat curing method. The method for manufacturing an opto-electric hybrid circuit board according to claim 12, wherein the first cladding layer, the core layer and the second cladding layer are formed by photocuring. The method for manufacturing an opto-electric hybrid circuit board according to claim 12, The microlens is formed by hot pressing a mold on the first cladding layer. The method of manufacturing an opto-electric hybrid circuit board according to claim 12, wherein the microlens is formed on the first cladding layer by photocuring. The method of manufacturing an opto-electric hybrid circuit board according to claim 12, wherein the microlens is formed on the first cladding layer by laser engraving. The method of manufacturing an opto-electric hybrid circuit board according to claim 12, wherein the microlens is formed on the first cladding layer by a diamond cutter cutting method.