Printed circuit board
The printed circuit board facilitates direct optical signal transmission and reception through an optical waveguide, eliminating the need for additional conversion components, thereby enhancing efficiency and reducing power consumption.
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- MITSUBISHI ELECTRIC CORP
- Filing Date
- 2024-12-27
- Publication Date
- 2026-07-09
Smart Images
Figure 2026115664000001_ABST
Abstract
Description
Technical Field
[0001] This disclosure relates to a printed wiring board.
Background Art
[0002] Conventionally, when mounting a semiconductor package on a printed wiring board, the printed wiring board and the semiconductor package were electrically connected by reflow soldering, and the semiconductor chip transmitted and received signals by an electrical signal. However, there was a problem that signal transmission and reception by an electrical signal consumed a large amount of power. Therefore, in recent years, a technique has been proposed in which a semiconductor chip transmits and receives signals by an optical signal.
[0003] For example, in the invention described in Patent Document 1, an optical module connector connected to an optical fiber is provided on a printed wiring board, and the optical module connector and the semiconductor chip are electrically connected. That is, the optical fiber is connected to the semiconductor chip via the optical module connector without passing through the printed wiring board. Then, the optical module connector converts the input optical signal and electrical signal with each other, enabling signal transmission and reception by the optical signal of the semiconductor chip.
Prior Art Documents
Patent Documents
[0004]
Patent Document 1
Summary of the Invention
Problems to be Solved by the Invention
[0005] However, in the invention described in Patent Document 1, as described above, there was a problem that in order for the semiconductor chip to transmit and receive an optical signal, it was necessary to pass through an optical module connector, which is an additional component for converting an optical signal and an electrical signal with each other.
[0006] This disclosure was made to solve the above-mentioned problems and aims to provide a printed circuit board that can transmit and receive optical signals to and from a semiconductor chip without the need for additional components to convert optical signals and electrical signals to and from each other. [Means for solving the problem]
[0007] The printed wiring board according to this disclosure is characterized by comprising: a substrate which is an insulator; a semiconductor chip provided on the substrate which has an optical signal transmitting and receiving unit on the substrate side that transmits and receives optical signals via an optical waveguide which is a path for optical signals; and an alignment structure provided between the substrate and the semiconductor chip which has an insertion hole for an optical waveguide on the semiconductor chip side at a position corresponding to the optical signal transmitting and receiving unit, through which an optical waveguide is inserted. [Effects of the Invention]
[0008] According to this disclosure, a printed circuit board can transmit and receive optical signals to and from a semiconductor chip without the need for additional components to convert optical signals and electrical signals to and from each other. [Brief explanation of the drawing]
[0009] [Figure 1] This is a schematic diagram of the printed circuit board according to Embodiment 1. [Figure 2] This is a schematic diagram of a conventional semiconductor chip. [Figure 3] This is a schematic diagram of the semiconductor chip according to Embodiment 1. [Figure 4] This is a schematic diagram of the alignment structure of Embodiment 1. [Figure 5] This is a schematic diagram showing the semiconductor chip and alignment structure of Embodiment 1 when combined. [Figure 6] This is a schematic diagram showing the connection between the optical signal transmitting / receiving unit and the optical waveguide in Embodiment 1. [Figure 7] This is a schematic diagram of an insertion hole for an optical waveguide having a tapered portion according to Embodiment 1. [Figure 8]This is a schematic diagram showing a combination of the semiconductor chip and the alignment structure having a tapered section and an insertion hole for an optical waveguide, according to Embodiment 1. [Figure 9] This is a schematic diagram of the alignment structure having a protrusion according to Embodiment 1. [Figure 10] This is a schematic diagram showing the semiconductor chip and alignment structure having a protrusion from Embodiment 1 combined together. [Figure 11] This is a schematic diagram of a printed circuit board equipped with multiple optical signal transmitting and receiving units and multiple optical waveguide insertion holes according to Embodiment 1. [Figure 12] This is a schematic diagram of a semiconductor chip equipped with multiple optical signal transmitting and receiving units according to Embodiment 1. [Figure 13] This is a schematic diagram of an alignment structure equipped with multiple optical waveguide insertion holes according to Embodiment 1. [Figure 14] This is a schematic diagram showing a combination of a semiconductor chip equipped with multiple optical signal transmitting and receiving units according to Embodiment 1 and an alignment structure equipped with multiple optical waveguide insertion holes. [Figure 15] This is a schematic diagram showing the connection between multiple optical signal transmitting / receiving units and multiple optical waveguides in Embodiment 1. [Figure 16] This is a schematic diagram of multiple insertion holes for optical waveguides having tapered portions according to Embodiment 1. [Figure 17] This is a schematic diagram showing a combination of a semiconductor chip equipped with multiple optical signal transmitting and receiving units according to Embodiment 1 and an alignment structure equipped with multiple optical waveguide insertion holes having tapered portions. [Figure 18] This is a schematic diagram showing a semiconductor chip equipped with multiple optical signal transmitting and receiving units according to Embodiment 1, and an alignment structure having a protrusion and multiple optical waveguide insertion holes, when combined. [Figure 19] This is a schematic diagram of the printed circuit board according to Embodiment 2. [Figure 20] This is a schematic diagram showing the connection between the optical signal transmitting / receiving unit and the optical waveguide in Embodiment 2. [Modes for carrying out the invention]
[0010] The printed wiring board according to the embodiment will be described below with reference to the drawings. The following embodiments are merely examples, and it is possible to appropriately combine the embodiments and appropriately modify each embodiment. In the drawings, the same reference numerals are given to the same configurations. Note that in each drawing, the relative dimensional relationships or shapes of the respective constituent members may be different from the actual ones.
[0011] Embodiment 1. The printed wiring board 1000 in Embodiment 1 will be described with reference to FIG. 1. FIG. 1 is a schematic diagram of the printed wiring board 1000 of Embodiment 1. FIG. 1A is a schematic diagram of the printed wiring board 1000 as viewed from the surface side, which is the side where the semiconductor chip 200 is mounted. Further, FIG. 1B is a schematic diagram of the printed wiring board 1000 as viewed from the back side, which is the side opposite to the surface. Further, FIG. 1C is a schematic diagram of the printed wiring board 1000 as viewed from the side surface, which is a surface other than the surface and the back surface. Further, FIG. 1D is a cross-sectional view of the printed wiring board 1000 as viewed from the side surface, which is a surface other than the surface and the back surface. Further, FIG. 1E is an enlarged view of a cross-section of the printed wiring board 1000 as viewed from the side surface, which is a surface other than the surface and the back surface. As shown in FIG. 1, the printed wiring board 1000 includes a base material 100, a semiconductor chip 200, and an alignment structure 300.
[0012] The base material 100 is an insulator made of an insulating material and is a flat substrate on which components such as the semiconductor chip 200 are supported. Although not shown, the base material 100 includes a basic configuration necessary for exhibiting the function as the printed wiring board 1000, that is, a copper foil for forming a circuit pattern and an electrical wiring connected to the semiconductor chip 200.
[0013] In Figure 1, the printed circuit board 1000 comprises a plurality of semiconductor chips 200 provided on a substrate 100, namely a first semiconductor chip 201 and a second semiconductor chip 202. When the plurality of semiconductor chips 200 are not distinguished, they are simply referred to as semiconductor chips 200. Although not shown in the figure, the semiconductor chips 200 are equipped with basic terminals such as power terminals and control signal terminals, and are connected to electrical wiring provided on the substrate 100. The semiconductor chips 200 are then soldered to the copper foil portions on the substrate 100, i.e., component mounting pads, enabling power supply to the semiconductor chips 200, transmission of control signals, other signal processing, and transmission and reception of optical signals.
[0014] Figure 2 is a schematic diagram of a conventional semiconductor chip 210. Figure 2A is a schematic diagram of the conventional semiconductor chip 210 viewed from the front surface, which is the side opposite to the side mounted on the printed circuit board 1000. Figure 2B is a schematic diagram of the conventional semiconductor chip 210 viewed from the back surface, which is the side mounted on the printed circuit board 1000. Figure 2C is a schematic diagram of the conventional semiconductor chip 210 viewed from a side surface, which is a side other than the front and back surfaces. Figure 3 is a schematic diagram of the semiconductor chip 200 of Embodiment 1. Figure 3A is a schematic diagram of the semiconductor chip 200 of Embodiment 1 viewed from the front surface, which is the side opposite to the side mounted on the printed circuit board 1000. Figure 2B is a schematic diagram of the semiconductor chip 200 of Embodiment 1 viewed from the back surface, which is the side mounted on the printed circuit board 1000.
[0015] As shown in Figures 2 and 3, the semiconductor chip 200 is composed of a substrate 203 such as silicon or gallium arsenide, and is equipped with solder bumps 204 for mounting on the substrate 100. Also, in Figure 3, the semiconductor chip 200 of Embodiment 1 differs from the conventional semiconductor chip 210 in that it is equipped with an optical signal transmitting / receiving unit 205. The optical signal transmitting / receiving unit 205 transmits and receives optical signals via an optical waveguide 401, which is a path for optical signals. The optical signal transmitting / receiving unit 205 consists of, for example, a laser diode that serves as a light source for the optical signal to be transmitted, a photodiode that detects the received optical signal, and a mirror for passing the optical signal through and transmitting it to the optical waveguide 401.
[0016] The first semiconductor chip 201 and the second semiconductor chip 202 are connected by an optical waveguide 401, which is a path for optical signals, and transmit and receive optical signals from each other. The optical waveguide 401 in Embodiment 1 is an optical fiber 402 with a circular cross-section. The optical fiber 402, which is the optical waveguide 401, is connected to the optical signal transmitting and receiving unit 205 of the semiconductor chip 200. Here, the connection part between the optical waveguide 401 and the semiconductor chip 200, that is, the connection part between the optical fiber 402 and the optical signal transmitting and receiving unit 205, is called the optical connect part 400. The optical connect part 400 is formed by the contact or joining of the optical fiber 402 and the optical signal transmitting and receiving unit 205. However, when joining the optical fiber 402 and the optical signal transmitting and receiving unit 205, a glass fusion process is required, so it is preferable to form it by bringing the optical fiber 402 and the optical signal transmitting and receiving unit 205 into contact.
[0017] When connecting an optical waveguide 401 to an optical signal transmitting / receiving unit 205 provided on a semiconductor chip 200 without using an optical module connector, which is an additional component for converting optical signals and electrical signals, the printed circuit board 1000 needs to minimize the misalignment of the optical connect unit 400. In other words, in order to connect the optical signal transmitting / receiving unit 205 and the optical waveguide 401 without misalignment, the printed circuit board 1000 needs to identify the position of the optical waveguide 401 connected to the optical signal transmitting / receiving unit 205, accurately position it, and further fix the optical waveguide 401 in an appropriate position.
[0018] For example, regarding the misalignment of the core portion of the optical fiber 402, that is, the radial misalignment of the optical fiber 402 relative to the optical signal transmitting / receiving section 205, in the case of a single-mode fiber, since the core diameter is 8 μm to 10 μm, the acceptable range of misalignment is approximately 1 μm or less. In the case of a multimode fiber, since the core diameter is 50 μm to 62.5 μm, the acceptable range of misalignment is approximately 2 μm to 4 μm. Generally, the diameter of the outer cladding is 125 μm, and the diameter of the coating is 250 μm.
[0019] Furthermore, for example, the allowable range for the angular misalignment of the connection surfaces of the optical fiber 402 and the optical signal transceiver 205 is 1 degree or less. In particular, in the case of single-mode fiber, the angular misalignment of the connection surfaces of the optical fiber 402 and the optical signal transceiver 205 significantly affects the loss of optical signals, so it is desirable to keep it to 0.5 degrees or less.
[0020] Furthermore, for example, the allowable range for the gap between the optical signal transmitting / receiving unit 205 and the end face of the tip of the optical fiber 402, that is, the axial displacement of the optical fiber 402 relative to the optical signal transmitting / receiving unit 205, is 10 μm or less. In particular, when high-precision connection is required, it is desirable to keep it to 5 μm or less.
[0021] As described above, radial misalignment, angular misalignment, or axial misalignment of the optical connect section 400 affects the loss of optical signals. Therefore, the printed circuit board 1000 includes an alignment structure 300 provided between the substrate 100 and the semiconductor chip 200, as shown in Figure 1, to pinpoint the position of the optical waveguide 401 connected to the optical signal transmitting / receiving section 205, to accurately position it, and to fix the optical waveguide 401 in an appropriate position.
[0022] Figure 4 is a schematic diagram of the alignment structure 300 of Embodiment 1. Figure 4A is a schematic diagram of the alignment structure 300 viewed from the front side, which is the side facing the semiconductor chip 200. Figure 4B is a schematic diagram of the alignment structure 300 viewed from the back side, which is the side facing the substrate 100. Figure 5 is a schematic diagram of the semiconductor chip 200 and the alignment structure 300 of Embodiment 1 when they are combined. Figure 5A is a schematic diagram of the semiconductor chip 200 and the alignment structure 300 viewed from the front side. Figure 5B is a schematic diagram of the semiconductor chip 200 and the alignment structure 300 viewed from the back side. Figure 5C is a schematic diagram of the semiconductor chip 200 and the alignment structure 300 viewed from the side. Figure 6 is a schematic diagram showing the connection between the optical signal transmitting / receiving unit 205 and the optical waveguide 401 of Embodiment 1. In Figure 6, for the sake of explanation, the surface of the semiconductor chip 200 is shown as transparent.
[0023] As shown in Figures 4, 5, and 6, the semiconductor chip 200 has an optical signal transmitting / receiving unit 205 on the substrate 100 side. The alignment structure 300 is provided with an optical waveguide insertion hole 301 at a position corresponding to the optical signal transmitting / receiving unit 205. Here, "insertion" is not limited to penetrating, but means inserting an object into a hole, and includes cases where one object is inserted into an object with a hole on only one side. In other words, insertion holes include those that are opened on only one side of an object and those that are opened on both sides of an object to penetrate the object. Therefore, the optical waveguide insertion hole 301 is not limited to penetrating from the front side, which is the semiconductor chip 200 side of the alignment structure 300, to the back side, which is the substrate 100 side, but also includes cases where it is provided on the front side of the alignment structure 300, but is not provided on the back side corresponding to the optical waveguide insertion hole 301 on the front side. Furthermore, in this case, as will be described later, the alignment structure 300 is provided with a notch 305 that extends in the lateral direction, which is a surface other than the semiconductor chip 200 side and the substrate 100 side, and communicates with the optical waveguide insertion hole 301.
[0024] As shown in Figure 4A, the optical waveguide insertion hole 301 is provided at least on the semiconductor chip 200 side of the alignment structure 300, which is provided between the substrate 100 and the semiconductor chip 200. Furthermore, in the alignment structure 300 of Embodiment 1, as shown in Figure 4B, the substrate 100 side also has an optical waveguide insertion hole 301, so the optical waveguide insertion hole 301 is a through hole that penetrates from the semiconductor chip 200 side to the substrate 100 side. The optical connect portion 400 may be formed inside the optical waveguide insertion hole 301, or it may be formed on the semiconductor chip 200 side of the optical waveguide insertion hole 301, that is, outside the optical waveguide insertion hole 301 and between the semiconductor chip 200 and the alignment structure 300. Here, in order to pinpoint the position of the optical fiber 402 and accurately position it, it is necessary to allow a certain distance for the optical fiber 402 to penetrate the optical waveguide insertion hole 301, that is, the thickness of the alignment structure 300. Therefore, it is more preferable for the optical connect portion 400 to be formed between the semiconductor chip 200 and the alignment structure 300.
[0025] Furthermore, the alignment structure 300 has solder bump insertion holes 302 through which the solder bumps 204 of the semiconductor chip 200 are inserted. When the semiconductor chip 200 and the alignment structure 300 are stacked and placed on the substrate 100, the solder bumps 204 penetrate the solder bump insertion holes 302 and come into contact with the substrate 100. Therefore, even if the alignment structure 300 is provided between the substrate 100 and the semiconductor chip 200, the semiconductor chip 200 can be mounted on the substrate 100.
[0026] As shown in Figures 1D and 1E, the substrate 100 has through-holes 101 that are in an unplated, insulated state. The alignment structure 300 has an optical waveguide insertion hole 301 that penetrates from the semiconductor chip 200 side to the substrate 100 side, at a position corresponding to the through-holes 101 of the substrate 100. The optical fiber 402 is inserted through the optical waveguide insertion hole 301 of the alignment structure 300 via the through-holes 101 and connected to the optical signal transmitting / receiving unit 205 of the semiconductor chip 200. As a result, the printed circuit board 1000 can accurately position the optical waveguide 401 connected to the optical signal transmitting / receiving unit 205 by identifying its position in the optical waveguide insertion hole 301 located at the position corresponding to the optical signal transmitting / receiving unit 205, and can also fix the optical waveguide 401 in an appropriate position.
[0027] As described above, the printed circuit board 1000 in Embodiment 1 comprises a substrate 100 which is an insulator, a semiconductor chip 200 which is provided on the substrate 100 and has an optical signal transmitting / receiving unit 205 on the substrate 100 side that transmits and receives optical signals via an optical waveguide 401 which is an optical signal path, and an alignment structure 300 which is provided between the substrate 100 and the semiconductor chip 200 and has an optical waveguide insertion hole 301 on the semiconductor chip 200 side which is provided at a position corresponding to the optical signal transmitting / receiving unit 205, and through which the optical waveguide 401 is inserted. With the above configuration, the printed circuit board 1000 in Embodiment 1 can accurately position the optical waveguide 401 connected to the optical signal transmitting / receiving unit 205 by identifying the position of the optical waveguide 401, and furthermore, the optical waveguide 401 can be fixed in an appropriate position. As a result, the printed circuit board 1000 of Embodiment 1 can connect the optical waveguide 401 to the optical signal transmitting / receiving unit 205 provided on the semiconductor chip 200, and thus can transmit and receive optical signals to and from the semiconductor chip 200 without the need for additional components to convert optical signals and electrical signals to and from each other.
[0028] Furthermore, the substrate 100 of Embodiment 1 has a through-hole 101, and the alignment structure 300 has an optical waveguide insertion hole 301 that penetrates from the semiconductor chip 200 side to the substrate 100 side at a position corresponding to the through-hole 101, and the optical waveguide 401 is an optical fiber 402 with a circular cross-section, which is inserted through the optical waveguide insertion hole 301 via the through-hole 101. With the above configuration, the printed circuit board 1000 of Embodiment 1 has the optical waveguide 401 inserted into the optical waveguide insertion hole 301 provided at a position corresponding to the optical signal transmitting and receiving unit 205, so the position of the optical waveguide 401 connected to the optical signal transmitting and receiving unit 205 can be identified and the position can be accurately determined, and the optical waveguide 401 can be fixed in an appropriate position. As a result, the printed circuit board 1000 of Embodiment 1 can connect the optical waveguide 401 to the optical signal transmitting / receiving unit 205 provided on the semiconductor chip 200, and thus can transmit and receive optical signals to and from the semiconductor chip 200 without the need for additional components to convert optical signals and electrical signals to and from each other.
[0029] Furthermore, as shown in Figures 1D and 1E, the through-hole 101 may have a tapered shape that widens toward the side where the semiconductor chip 200 and the alignment structure 300 are not provided, i.e., toward the back side of the base material 100. This allows the printed circuit board 1000 to easily guide the optical fiber 402 into the optical waveguide insertion hole 301 of the alignment structure 300.
[0030] Figure 7 is a schematic diagram of the optical waveguide insertion hole 301 having a tapered portion 303 according to Embodiment 1. Figure 7A is a schematic diagram of the optical waveguide insertion hole 301 having a tapered portion 303 viewed from the front side. Figure 7B is a schematic diagram of the optical waveguide insertion hole 301 having a tapered portion 303 viewed from the back side. Figure 7C is a cross-sectional view of the optical waveguide insertion hole 301 having a tapered portion 303 viewed from the side. Figure 8 is a schematic diagram of the alignment structure 300 when the semiconductor chip 200 and the optical waveguide insertion hole 301 having a tapered portion 303 according to Embodiment 1 are combined. Figure 8A is a schematic diagram of the alignment structure 300 having the semiconductor chip 200 and the optical waveguide insertion hole 301 having a tapered portion 303 viewed from the front side. Figure 8B is a schematic diagram of the alignment structure 300, which includes a semiconductor chip 200 and an optical waveguide insertion hole 301 with a tapered portion 303, as viewed from the back side. Figure 8C is a schematic diagram of the alignment structure 300, which includes a semiconductor chip 200 and an optical waveguide insertion hole 301 with a tapered portion 303, as viewed from the side side. Figure 8D is a cross-sectional view of the alignment structure 300, which includes a semiconductor chip 200 and an optical waveguide insertion hole 301 with a tapered portion 303, as viewed from the side side.
[0031] As shown in Figures 7 and 8, the optical waveguide insertion hole 301 of the alignment structure 300 may have a tapered portion 303 that widens from the semiconductor chip 200 side toward the substrate 100 side. This allows the printed circuit board 1000 to easily guide the optical fiber 402 into the optical waveguide insertion hole 301 of the alignment structure 300.
[0032] Figure 9 is a schematic diagram of the alignment structure 300 having the protrusion 304 according to Embodiment 1. Figure 9A is a schematic diagram of the alignment structure 300 having the protrusion 304 viewed from the front side. Figure 9B is a cross-sectional view of the alignment structure 300 having the protrusion 304 viewed from the side side. Figure 10 is a schematic diagram of the semiconductor chip 200 and the alignment structure 300 having the protrusion 304 according to Embodiment 1 when combined. Figure 10A is a schematic diagram of the semiconductor chip 200 and the alignment structure 300 having the protrusion 304 viewed from the front side. Figure 10B is a schematic diagram of the semiconductor chip 200 and the alignment structure 300 having the protrusion 304 viewed from the back side. Figure 10C is a schematic diagram of the semiconductor chip 200 and the alignment structure 300 having the protrusion 304 viewed from the side side. Figure 10D is a cross-sectional view of the semiconductor chip 200 and the alignment structure 300 having the protrusion 304 viewed from the side side.
[0033] As shown in Figures 9 and 10, the alignment structure 300 may have a protrusion 304 into which the semiconductor chip 200 can be fitted. As shown in Figure 10, the protrusion 304 is, for example, a wall-shaped member that protrudes toward the semiconductor chip 200 so as to surround all four sides of the semiconductor chip 200 when the semiconductor chip 200 is placed on the alignment structure 300. As a result, the printed circuit board 1000 can more accurately position the optical waveguide 401 connected to the optical signal transmitting / receiving unit 205 because the semiconductor chip 200 is fixed to the alignment structure 300, and can also fix the optical waveguide 401 in a more appropriate position.
[0034] Figure 11 is a schematic diagram of a printed circuit board 1000 equipped with multiple optical signal transmitting / receiving units 205 and multiple optical waveguide insertion holes 301 according to Embodiment 1. Figure 11A is a schematic diagram of the printed circuit board 1000 equipped with multiple optical signal transmitting / receiving units 205 and multiple optical waveguide insertion holes 301 viewed from the front side. Figure 11B is a schematic diagram of the printed circuit board 1000 equipped with multiple optical signal transmitting / receiving units 205 and multiple optical waveguide insertion holes 301 viewed from the back side. Figure 12 is a schematic diagram of a semiconductor chip 200 equipped with multiple optical signal transmitting / receiving units 205 according to Embodiment 1. Figure 12A is a schematic diagram of the semiconductor chip 200 equipped with multiple optical signal transmitting / receiving units 205 viewed from the front side. Figure 12B is a schematic diagram of the semiconductor chip 200 equipped with multiple optical signal transmitting / receiving units 205 viewed from the back side. Figure 12C is a schematic diagram of the semiconductor chip 200 equipped with multiple optical signal transmitting / receiving units 205 viewed from the side side. Figure 13 is a schematic diagram of the alignment structure 300 equipped with multiple optical waveguide insertion holes 301 according to Embodiment 1. Figure 13A is a schematic diagram of the alignment structure 300 equipped with multiple optical waveguide insertion holes 301 viewed from the front side. Figure 13B is a schematic diagram of the alignment structure 300 equipped with multiple optical waveguide insertion holes 301 viewed from the back side. Figure 14 is a schematic diagram of the case when the semiconductor chip 200 equipped with multiple optical signal transmitting and receiving units 205 and the alignment structure 300 equipped with multiple optical waveguide insertion holes 301 according to Embodiment 1 are combined. Figure 14A is a schematic diagram of the semiconductor chip 200 equipped with multiple optical signal transmitting and receiving units 205 and the alignment structure 300 equipped with multiple optical waveguide insertion holes 301 viewed from the front side. Figure 14B is a schematic view from the back of a semiconductor chip 200 equipped with multiple optical signal transmitting / receiving units 205 and an alignment structure 300 equipped with multiple optical waveguide insertion holes 301. Figure 14C is a schematic view from the side of a semiconductor chip 200 equipped with multiple optical signal transmitting / receiving units 205 and an alignment structure 300 equipped with multiple optical waveguide insertion holes 301. Figure 15 is a schematic diagram showing the connection between the multiple optical signal transmitting / receiving units 205 and the multiple optical waveguides 401 of Embodiment 1.
[0035] As shown in Figure 11, the printed circuit board 1000 may be configured such that a first semiconductor chip 201 and a second semiconductor chip 202 are connected by a plurality of optical fibers 402, which are a plurality of optical waveguides 401. In this case, as shown in Figure 12, the semiconductor chip 200 has a plurality of optical signal transmitting and receiving units 205 to which the plurality of optical fibers 402 are connected.
[0036] Furthermore, as shown in Figures 13 and 14, the alignment structure 300 has at least a plurality of optical waveguide insertion holes 301 on the semiconductor chip 200 side, which are provided at positions corresponding to each of the plurality of optical signal transmitting and receiving units 205 of the semiconductor chip 200. Note that in Figures 13 and 14, the alignment structure 300 also has optical waveguide insertion holes 301 on the substrate 100 side, and these optical waveguide insertion holes 301 are through holes that penetrate from the semiconductor chip 200 side to the substrate 100 side.
[0037] As shown in Figure 15, multiple optical waveguides 401, which are optical fibers 402, are inserted through multiple optical waveguide insertion holes 301 provided at positions corresponding to each of the optical signal transmitting and receiving units 205. As a result, the printed circuit board 1000 can transmit and receive optical signals with a higher transmission density compared to when there is only one optical waveguide 401.
[0038] Figure 16 is a schematic diagram of the multiple optical waveguide insertion holes 301 having tapered portions 303 according to Embodiment 1. Figure 16A is a schematic diagram of the alignment structure 300 having multiple optical waveguide insertion holes 301 having tapered portions 303, viewed from the front side. Figure 16B is a schematic diagram of the alignment structure 300 having multiple optical waveguide insertion holes 301 having tapered portions 303, viewed from the back side. Figure 16C is a cross-sectional view of the alignment structure 300 having multiple optical waveguide insertion holes 301 having tapered portions 303, viewed from the side.
[0039] Figure 17 is a schematic diagram of a combination of the semiconductor chip 200 equipped with multiple optical signal transmitting and receiving units 205 and the alignment structure 300 equipped with multiple optical waveguide insertion holes 301 having tapered portions 303 according to Embodiment 1. Figure 17A is a schematic diagram of the semiconductor chip 200 equipped with multiple optical signal transmitting and receiving units 205 and the alignment structure 300 equipped with multiple optical waveguide insertion holes 301 having tapered portions 303, viewed from the front side. Figure 17B is a schematic diagram of the semiconductor chip 200 equipped with multiple optical signal transmitting and receiving units 205 and the alignment structure 300 equipped with multiple optical waveguide insertion holes 301 having tapered portions 303, viewed from the back side. Figure 17C is a schematic diagram of the semiconductor chip 200 equipped with multiple optical signal transmitting and receiving units 205 and the alignment structure 300 equipped with multiple optical waveguide insertion holes 301 having tapered portions 303, viewed from the side side. Figure 17D is a cross-sectional view from the side of a semiconductor chip 200 equipped with multiple optical signal transmitting and receiving units 205 and an alignment structure 300 equipped with multiple optical waveguide insertion holes 301 having tapered portions 303.
[0040] Figure 18 is a schematic diagram of a combination of the semiconductor chip 200 equipped with multiple optical signal transmitting and receiving units 205 according to Embodiment 1, and the alignment structure 300 having a protrusion 304 and multiple optical waveguide insertion holes 301. Figure 18A is a schematic diagram of the semiconductor chip 200 equipped with multiple optical signal transmitting and receiving units 205 and the alignment structure 300 having a protrusion 304 and multiple optical waveguide insertion holes 301, viewed from the front side. Figure 18B is a schematic diagram of the semiconductor chip 200 equipped with multiple optical signal transmitting and receiving units 205 and the alignment structure 300 having a protrusion 304 and multiple optical waveguide insertion holes 301, viewed from the back side. Figure 18C is a schematic diagram of the semiconductor chip 200 equipped with multiple optical signal transmitting and receiving units 205 and the alignment structure 300 having a protrusion 304 and multiple optical waveguide insertion holes 301, viewed from the side side. Figure 18D is a cross-sectional view from the side of a semiconductor chip 200 equipped with multiple optical signal transmitting and receiving units 205, and an alignment structure 300 having a protrusion 304 and multiple optical waveguide insertion holes 301.
[0041] As shown in Figures 16, 17, and 18, even if the printed circuit board 1000 has a semiconductor chip 200 having a plurality of optical signal transmitting and receiving units 205 and an alignment structure 300 having a plurality of optical waveguide insertion holes 301 provided at positions corresponding to each of the plurality of optical signal transmitting and receiving units 205, the optical waveguide insertion holes 301 of the alignment structure 300 may have tapered portions 303 that widen from the semiconductor chip 200 side toward the substrate 100 side, or the alignment structure 300 may have protrusions 304 into which the semiconductor chip 200 can be fitted.
[0042] Furthermore, although the printed circuit board 1000 has been described as having a configuration comprising a first semiconductor chip 201 and a second semiconductor chip 202, that is, a configuration comprising two semiconductor chips 200, it is not limited to this, and may have three or more semiconductor chips 200, each connected by an optical waveguide 401.
[0043] Furthermore, the components connected by the optical waveguide 401 are not limited to the semiconductor chip 200. For example, the printed circuit board 1000 may be configured such that components other than the semiconductor chip 200, such as an optical module, are connected to the semiconductor chip 200 by the optical waveguide 401.
[0044] Embodiment 2. The printed circuit board 1001 in Embodiment 2 will now be described. In Embodiment 1, the printed circuit board 1000 was configured such that the first semiconductor chip 201 and the second semiconductor chip 202 were connected by an optical fiber 402 with a circular cross-section, which served as an optical waveguide 401. In contrast, the printed circuit board 1001 in Embodiment 2 differs from the printed circuit board 1000 in that the first semiconductor chip 201 and the second semiconductor chip 202 are connected by an optical waveguide 401 with a square cross-section. Components similar to those in Embodiment 1 are denoted by the same reference numerals. Furthermore, a detailed explanation of components similar to those in Embodiment 1 will be omitted, and the differences from Embodiment 1 will be described primarily.
[0045] Figure 19 is a schematic diagram of the printed circuit board 1001 of Embodiment 2. Figure 19A is a schematic diagram of the printed circuit board 1001 viewed from the front side. Figure 19B is a schematic diagram of the printed circuit board 1001 viewed from the back side. Figure 20 is a schematic diagram showing the connection between the optical signal transmitting / receiving unit 205 and the optical waveguide 401 of Embodiment 2.
[0046] As described above, in the printed circuit board 1001 of Embodiment 2, as shown in Figures 19 and 20, the first semiconductor chip 201 and the second semiconductor chip 202 are connected by an optical waveguide 401 with a rectangular cross-section. In this case, the optical waveguide 401 is, for example, a slab optical waveguide and a rectangular optical waveguide.
[0047] As shown in Figure 20, the alignment structure 300 has a notch 305 that extends in the lateral direction, which is a surface other than the semiconductor chip 200 side and the substrate 100 side. This notch 305 communicates with the optical waveguide insertion hole 301, and guides the optical waveguide 401 from outside the semiconductor chip 200 to the optical waveguide insertion hole 301. In other words, the optical waveguide 401 is inserted into the optical waveguide insertion hole 301 via the notch 305.
[0048] Furthermore, in this case, the optical waveguide insertion hole 301 is provided on the semiconductor chip 200 side of the alignment structure 300 provided between the substrate 100 and the semiconductor chip 200, similar to Embodiment 1. On the other hand, since the alignment structure 300 of Embodiment 2 does not have the optical waveguide insertion hole 301 on the substrate 100 side, the optical waveguide insertion hole 301 does not penetrate from the semiconductor chip 200 side to the substrate 100 side.
[0049] The printed circuit board 1001 in Embodiment 2, similar to Embodiment 1, comprises a substrate 100 which is an insulator, a semiconductor chip 200 provided on the substrate 100 and having an optical signal transmitting / receiving unit 205 on the substrate 100 side that transmits and receives optical signals via an optical waveguide 401 which is an optical signal path, and an alignment structure 300 provided between the substrate 100 and the semiconductor chip 200, having an optical waveguide insertion hole 301 on the semiconductor chip 200 side located at a position corresponding to the optical signal transmitting / receiving unit 205, through which the optical waveguide 401 is inserted. With the above configuration, the printed circuit board 1001 of Embodiment 2 can accurately position the optical waveguide 401 connected to the optical signal transmitting / receiving unit 205 by identifying the position of the optical waveguide 401, and furthermore, the optical waveguide 401 can be fixed in an appropriate position. As a result, the printed circuit board 1001 of the second embodiment can connect the optical waveguide 401 to the optical signal transmitting / receiving unit 205 provided on the semiconductor chip 200, and thus can transmit and receive optical signals to and from the semiconductor chip 200 without the need for additional components to convert optical signals and electrical signals to and from each other.
[0050] Furthermore, the alignment structure 300 of Embodiment 2 extends in the lateral direction, which is a surface other than the semiconductor chip 200 side and the substrate 100 side, and has a notch 305 that communicates with the optical waveguide insertion hole 301. The optical waveguide 401 has a square cross-section and is inserted into the optical waveguide insertion hole 301 via the notch 305. With the above configuration, the printed circuit board 1001 of Embodiment 2 has the optical waveguide 401 inserted into the optical waveguide insertion hole 301 provided at a position corresponding to the optical signal transmitting and receiving unit 205. Therefore, the position of the optical waveguide 401 connected to the optical signal transmitting and receiving unit 205 can be identified and its positioning can be accurately performed, and the optical waveguide 401 can be fixed in an appropriate position. As a result, the printed circuit board 1001 of the second embodiment can connect the optical waveguide 401 to the optical signal transmitting / receiving unit 205 provided on the semiconductor chip 200, and thus can transmit and receive optical signals to and from the semiconductor chip 200 without the need for additional components to convert optical signals and electrical signals to and from each other.
[0051] In Embodiment 2, the alignment structure 300 may have a protrusion 304 into which the semiconductor chip 200 can be fitted, similar to Embodiment 1. Also, in Embodiment 2, the printed circuit board 1001 may have a configuration similar to Embodiment 1, where the semiconductor chip 200 has a plurality of optical signal transmitting and receiving units 205, and the alignment structure 300 has a plurality of optical waveguide insertion holes 301 provided at positions corresponding to each of the plurality of optical signal transmitting and receiving units 205, with a plurality of optical waveguides inserted into each of the plurality of optical waveguide insertion holes. In this case, the alignment structure 300 in Embodiment 2 has a plurality of notches 305.
[0052] (Note 1) An insulating substrate, A semiconductor chip provided on the substrate and having an optical signal transmitting / receiving unit on the substrate side that transmits and receives the optical signal via an optical waveguide which is a path for the optical signal, An alignment structure is provided between the substrate and the semiconductor chip, having an insertion hole for an optical waveguide on the semiconductor chip side at a position corresponding to the optical signal transmitting and receiving unit, through which the optical waveguide is inserted; A printed circuit board equipped with the following features. (Note 2) The substrate has through holes, The alignment structure has an insertion hole for the optical waveguide that penetrates from the semiconductor chip side to the substrate side at a position corresponding to the through hole, The optical waveguide is an optical fiber with a circular cross-section, which is inserted through the through-hole into the optical waveguide insertion hole. The printed circuit board described in Appendix 1. (Note 3) The alignment structure extends in the lateral direction, which is a surface other than the semiconductor chip side and the substrate side, and has a notch that communicates with the optical waveguide insertion hole 301. The optical waveguide has a square cross-section and is inserted through the notch into the optical waveguide insertion hole. The printed circuit board described in Appendix 1. (Note 4) The optical waveguide insertion hole of the alignment structure has a tapered portion that widens from the semiconductor chip side toward the substrate side. A printed circuit board as described in either Appendix 1 or Appendix 2. (Note 5) The alignment structure has a protrusion into which the semiconductor chip can be fitted, A printed circuit board as described in any one of the items from Appendix 1 to Appendix 4. (Note 6) The semiconductor chip has a plurality of optical signal transmitting and receiving units, The alignment structure has a plurality of optical waveguide insertion holes on the semiconductor chip side, provided at positions corresponding to each of the plurality of optical signal transmitting and receiving units, and a plurality of optical waveguides are inserted through each of the plurality of optical waveguide insertion holes. A printed circuit board as described in any one of the items from Appendix 1 to Appendix 5. [Explanation of Symbols]
[0053] 1000, 1001 Printed circuit board, 100 Substrate, 101 Through-hole, 200 Semiconductor chip, 201 First semiconductor chip, 202 Second semiconductor chip, 203 Substrate, 204 Solder bump, 205 Optical signal transmitting / receiving section, 210 Conventional semiconductor chip, 300 Alignment structure, 301 Through-hole for optical waveguide, 302 Through-hole for solder bump, 303 Tapered section, 304 Protrusion, 305 Notch, 400 Optical connect section, 401 Optical waveguide, 402 Optical fiber
Claims
1. An insulating substrate, A semiconductor chip provided on the substrate and having an optical signal transmitting / receiving unit on the substrate side that transmits and receives the optical signal via an optical waveguide which is a path for the optical signal, An alignment structure is provided between the substrate and the semiconductor chip, having an insertion hole for an optical waveguide on the semiconductor chip side at a position corresponding to the optical signal transmitting and receiving unit, through which the optical waveguide is inserted; A printed circuit board equipped with the following features.
2. The substrate has through holes, The alignment structure has an insertion hole for the optical waveguide that penetrates from the semiconductor chip side to the substrate side at a position corresponding to the through hole, The optical waveguide is an optical fiber with a circular cross-section, which is inserted through the through-hole into the optical waveguide insertion hole. The printed circuit board according to claim 1.
3. The alignment structure extends in the lateral direction, which is a surface other than the semiconductor chip side and the substrate side, and has a notch that communicates with the optical waveguide insertion hole. The optical waveguide has a square cross-section and is inserted through the notch into the optical waveguide insertion hole. The printed circuit board according to claim 1.
4. The optical waveguide insertion hole of the alignment structure has a tapered portion that widens from the semiconductor chip side toward the substrate side. The printed circuit board according to claim 1.
5. The alignment structure has a protrusion into which the semiconductor chip can be fitted, The printed circuit board according to claim 1.
6. The semiconductor chip has a plurality of optical signal transmitting and receiving units, The alignment structure has a plurality of optical waveguide insertion holes on the semiconductor chip side, provided at positions corresponding to each of the plurality of optical signal transmitting and receiving units, and a plurality of optical waveguides are inserted through each of the plurality of optical waveguide insertion holes. The printed circuit board according to claim 1.