Multi-chip module, device, data center, and method for manufacturing multi-chip module

Abstract

A multi-chip module according to the present disclosure comprises: a plurality of package substrates arranged in a horizontal direction; a plurality of logic ICs arranged on the plurality of package substrates; photoelectric control ICs each arranged on a peripheral portion, among the peripheral portions of the plurality of logic ICs, located at an outer peripheral portion of the multi-chip module; optical ICs each arranged on a corresponding one of the photoelectric control ICs; optical connection portions arranged on the optical ICs; optical wiring connected to the optical connection portions; a wiring pedestal arranged on a peripheral portion, among the peripheral portions of the plurality of logic ICs, facing a peripheral portion of a logic IC arranged on an adjacent package substrate; electrical bridge wiring connected to the wiring pedestal; and a reinforcing fixing frame that fixes the plurality of package substrates.

Description

Multichip Module, Apparatus, Data Center, and Method for Manufacturing Multichip Module

[0001] The present disclosure relates to a multichip module in which logic ICs are integrated and a method for manufacturing the same.

[0002] In large-scale parallel signal processing, many logic ICs such as GPUs and accelerators are used. In order to cooperate the logic ICs to perform high-speed processing, it is important to reduce the time required for data transmission between logic ICs, that is, to achieve low latency (Non-Patent Document 1, Non-Patent Document 2).

[0003] In order to connect logic ICs with low latency, it is effective to mount a plurality of logic ICs on the same package and shorten the distance between each logic IC.

[0004] Hisa Ando, “NVIDIA's Next-Generation AI Research Chip is a Scalable Inference Accelerator”, September 30, 2013, Internet, <URL: https: / / news.mynavi.jp / techplus / article / hotchips31_ml-13 / >Will Knight, “Clustering Giant Chips, the Potential of Technology that Dramatically Improves AI Capabilities”, September 7, 2021, Internet, <URL: https: / / wired.jp / 2021 / 09 / 07 / cerebras-chip-cluster-neural-networks-ai / >

[0005] However, there are restrictions on the size of the package substrate from the viewpoints of package substrate warpage and wiring formation. As a result, the number of logic ICs that can be connected with low latency is limited.

[0006] In addition, a larger logic IC can accommodate more arithmetic devices, so the arithmetic capability can be improved. However, increasing the size of a logic IC reduces the number of logic ICs that can be mounted on the same package substrate.

[0007] As described above, there has been a problem that a large number of high-performance logic ICs cannot be integrated on a package substrate.

[0008] Furthermore, when logic ICs are arranged in a two-dimensional array, communication between logic ICs located at different positions relies on logic ICs placed between them to relay the data. As a result, the problem was that latency increased as the number of relays increased.

[0009] Furthermore, logic ICs located near the center of the package substrate frequently relay data from surrounding logic ICs, making it highly likely that traffic will concentrate and data transmission will be delayed. As a result, increased latency was a problem.

[0010] To solve the problems described above, the multichip module according to this disclosure is a multichip module comprising: a plurality of package substrates arranged horizontally; a plurality of logic ICs arranged on the package substrates; a photoelectric control IC arranged on the peripheral edge of the plurality of logic ICs, which is located on the outer periphery of the multichip module; an optical IC arranged on the photoelectric control IC; an optical connection portion arranged on the optical IC; optical wiring connected to the optical connection portion; a wiring frame arranged on the peripheral edge of the plurality of logic ICs, which is located on the peripheral edge of an adjacent logic IC arranged on the package substrate; electrical bridge wiring connected to the wiring frame; and a reinforcing fixing frame for fixing the plurality of package substrates.

[0011] Furthermore, the multichip module according to this disclosure is a multichip module comprising: a plurality of package substrates arranged horizontally; a plurality of logic ICs arranged on the package substrates; photoelectric / electrical control ICs arranged on the peripheral edge of the logic ICs, which is located on the outer periphery of the package substrates; an optical IC arranged on the photoelectric / electrical control ICs located on the outer periphery of the multichip module; an optical connection portion arranged on the optical IC; an optical wiring connected to the optical connection portion; an electrical bridge wiring connected to the photoelectric / electrical control ICs located on the peripheral edge of the logic ICs, which is facing the peripheral edge of the logic ICs arranged on adjacent package substrates; and a reinforcing fixing frame for fixing the plurality of package substrates.

[0012] Furthermore, the manufacturing method for a multi-chip module mounting substrate according to this disclosure is a manufacturing method for a substrate on which a multi-chip module is mounted on a printed circuit board, wherein a plurality of logic ICs are mounted on a package substrate, and either a photoelectric control IC or a photoelectric / electrical control IC is mounted on the peripheral edge of the plurality of logic ICs that is arranged on the outer periphery of the multi-chip module, and a wiring frame and a photoelectric control IC are mounted on the peripheral edge of the plurality of logic ICs that is facing the peripheral edge of an adjacent logic IC arranged on the package substrate. The process includes the steps of: mounting either the photoelectric control IC or the optical IC; fixing the plurality of package substrates via a reinforcing fixing frame; connecting an electrical bridge wiring to either the wiring frame or the photoelectric / electrical control IC; mounting the optical IC on either the photoelectric control IC or the photoelectric / electrical control IC; mounting an optical connection part on the optical IC; connecting an optical wiring to the optical connection part; and mounting the plurality of package substrates fixed via the reinforcing fixing frame onto the printed circuit board.

[0013] According to this disclosure, it is possible to provide a multi-chip module that can integrate a number of logic ICs and connect each logic IC with low latency, as well as a method for manufacturing the same.

[0014] Figure 1A is a schematic top view showing the configuration of a multi-chip module according to the first embodiment of this disclosure. Figure 1B is a schematic side view showing the configuration of the side cross-section and optical wiring of a multi-chip module mounting substrate on which the multi-chip module according to the first embodiment of this disclosure is mounted. Figure 1C is a schematic cross-sectional view showing the configuration of the reinforcing fixing frame in the multi-chip module according to the first embodiment of this disclosure. Figure 2A is a schematic top view for explaining the manufacturing method of the multi-chip module according to the first embodiment of this disclosure. Figure 2B is a schematic side cross-sectional view for explaining the manufacturing method of the multi-chip module according to the first embodiment of this disclosure. Figure 3A is a schematic top view for explaining the manufacturing method of the multi-chip module according to the first embodiment of this disclosure. Figure 3B is a schematic side cross-sectional view for explaining the manufacturing method of the multi-chip module according to the first embodiment of this disclosure. Figure 4A is a schematic top view for explaining the manufacturing method of the multi-chip module according to the first embodiment of this disclosure. Figure 4B is a schematic side cross-sectional view showing the configuration of the side cross-section and optical wiring for explaining the manufacturing method of the multi-chip module according to the first embodiment of this disclosure. Figure 5A is a schematic side cross-sectional view for explaining a conventional manufacturing method of a multi-chip module mounting substrate. Figure 5B is a schematic diagram showing the configuration of a side cross-section and optical wiring for illustrating a conventional method of manufacturing a multi-chip module mounting substrate. Figure 5C is a schematic diagram showing the configuration of a side cross-section and optical wiring for illustrating a conventional method of manufacturing a multi-chip module mounting substrate. Figure 6A is a schematic top view showing the configuration of a multi-chip module according to the second embodiment of this disclosure. Figure 6B is a schematic diagram showing the configuration of a side cross-section and optical wiring of a multi-chip module mounting substrate on which the multi-chip module according to the second embodiment of this disclosure is mounted. Figure 7A is a block diagram illustrating the photoelectric / electrical control IC in the multi-chip module according to the second embodiment of this disclosure. Figure 7B is a block diagram illustrating the photoelectric / electrical control IC in the multi-chip module according to the second embodiment of this disclosure. Figure 8A is a schematic top view illustrating the method of manufacturing a multi-chip module according to the second embodiment of this disclosure.Figure 8B is a schematic side cross-sectional view illustrating a method for manufacturing a multi-chip module according to a second embodiment of the present disclosure. Figure 9A is a schematic top view illustrating a method for manufacturing a multi-chip module according to a second embodiment of the present disclosure. Figure 9B is a schematic side cross-sectional view illustrating a method for manufacturing a multi-chip module according to a second embodiment of the present disclosure. Figure 10A is a schematic top view illustrating a method for manufacturing a multi-chip module according to a second embodiment of the present disclosure. Figure 10B is a schematic diagram showing the configuration of the side cross-section and the optical wiring configuration illustrating a method for manufacturing a multi-chip module according to a second embodiment of the present disclosure.

[0015] <First Embodiment> A multi-chip module according to the first embodiment of this disclosure will be described with reference to Figures 1A to 5C.

[0016] <Configuration of the Multi-Chip Module> As shown in Figures 1A and 1B, the multi-chip module 10 according to this embodiment comprises a plurality of package substrates 11, a logic IC 12, a photoelectric control IC 13, an optical IC 14, an optical connection section 15, optical wiring 16, a wiring frame 17, an electrical bridge wiring 18, and a reinforcing fixing frame 19.

[0017] Multiple package substrates 11 are arranged on a horizontal plane. Hereinafter, "horizontal direction" refers to the direction parallel to the upper surface of the package substrate 11. "Vertical direction" refers to the direction perpendicular to the upper surface of the package substrate 11.

[0018] The size of the package substrate 11 may be, for example, about 10 cm x 10 cm. The thickness of the package substrate 11 may be, for example, about 1.5 mm. The spacing between the package substrates 11 arranged on a horizontal plane may be, for example, about 0.5 cm to 1.0 cm.

[0019] As shown in Figure 1B, the package substrate 11 is provided with an electrical connection section 102 on its bottom surface. The package substrate 11 is electrically connected to the power supply and signal transmission electrical wiring of the printed circuit board (PCB) 101 via the electrical connection section 102. The electrical connection section 102 may be BGA, PGA, or LGA, or other electrical connection methods may be used. In this way, the multi-chip module mounting board is constructed from the multi-chip module 10 and the printed circuit board (PCB) 101.

[0020] Multiple logic ICs 12 are arranged on the package substrate 11. The size of the logic ICs 12 may be, for example, about 3 cm x 3 cm. The thickness of the multiple logic ICs 12 may be, for example, about 0.8 mm. The logic ICs 12 may be arranged at intervals of about 0.5 μm.

[0021] The photoelectric control IC 13 is positioned on the peripheral edge of the logic IC 12, which is located on the outer periphery of the multi-chip module 10. For example, the peripheral edge of the logic IC 12 may be the end face of the logic IC 12, or it may be the upper surface near the peripheral edge of the logic IC 12.

[0022] The optical IC 14 is arranged on the photoelectric control IC 13. The optical IC 14 comprises an optical modulation element and a photodetector. For example, the optical modulation element is a directly modulated laser. Alternatively, the optical modulation element may comprise a semiconductor laser and an external modulator, and the light emitted by the semiconductor laser may be modulated by the external modulator.

[0023] The optical IC 14 converts optical signals to electrical signals. The optical IC 14 is optically connected to another optical IC 14 on a package substrate 11 via optical wiring 16, and transmits and receives optical signals between the package substrates 11. The size of the optical IC 14 may be, for example, about 3 cm x 3 cm. The thickness of the optical IC 14 may be, for example, about 0.5 mm.

[0024] In the multi-chip module 10, the photoelectric control IC 13 drives the optical IC 14 based on the output signal from the logic IC 12. The photoelectric control IC 13 also amplifies the electrical signal converted from the optical signal by the optical IC 14 and outputs it to the logic IC 12.

[0025] The optical IC 14 and the optical wiring 16 are optically connected at the optical connection section 15. The optical wiring 16 may be made of fiber, resin ribbon, etc. The optical connection section 15 may be made of fiber array, fiber block, etc.

[0026] The optical IC 14 and the multiple logic ICs 12 are electrically connected via the electrical wiring of the package substrate 11.

[0027] The wiring support frame 17 is positioned on the end faces of the logic ICs 12 facing each other between adjacent package substrates 11. For example, the wiring support frame 17 is made of resin and includes metal wiring.

[0028] The electrical bridge wiring 18 is connected to the wiring frame 17 and connects adjacent logic ICs 12 between package boards 11.

[0029] In this configuration, the logic IC 12 and the electrical bridge wiring 18 are electrically connected via the metal wiring of the wiring frame 17.

[0030] Furthermore, the height of the wiring frame 17 is greater than the thickness of the beam portion 192 (described later) of the reinforcing fixing frame 19. This allows the electrical bridge wiring 18 to bridge the gap between the logic ICs 12, preventing the electrical bridge wiring 18 from interfering with the beam portion 192 of the reinforcing fixing frame 19.

[0031] In this way, opposing logic ICs 12 are electrically connected between adjacent package substrates 11 via an electrical bridge wiring 18 over a short distance of, for example, 0.5 cm to 1.0 cm. On the other hand, logic ICs 12 arranged on the outer periphery of the multi-chip module 10 are optically connected.

[0032] The reinforcing fixing frame 19 is made of metal or resin. A metal construction of the reinforcing fixing frame 19 can improve heat dissipation. The reinforcing fixing frame 19 fixes (attaches) the package substrates 11 to each other in a plurality of package substrates 11. This allows the plurality of package substrates 11 to be integrated. The reinforcing fixing frame 19 may be configured in a grid pattern when viewed from above, as shown in Figure 1A.

[0033] More specifically, as shown in Figure 1C, the reinforcing fixing frame 19 comprises a base portion 191 and a beam portion 192. The reinforcing fixing frame 19 may have a T-shaped cross-section.

[0034] The base portion 191 extends perpendicularly to the upper surface of the package substrate 11 (the surface on which the logic IC 12 and optical IC 14 are mounted) and is positioned between opposing end faces of adjacent package substrates 11. The width of the base portion 191 is, for example, about 0.5 mm to 1.0 mm. The base portion 191 may also be positioned on the outer periphery of the multi-chip module 10.

[0035] The beam portion 192 is provided at one end of the base portion 191 and extends perpendicular to the opposing end faces of the adjacent package substrates 11. The beam portion 192 extends toward the sides of both adjacent package substrates 11. The beam portion 192 is positioned such that its bottom surface abuts against the upper surfaces of the adjacent package substrates 11. In the reinforcing fixing frame 19, the beam portion 192 provided on the base portion 191, which is positioned on the outer periphery of the multi-chip module 10, may extend only toward the inside of the multi-chip module 10.

[0036] This allows the upper surfaces of the package substrate 11 to be defined on substantially the same horizontal plane. As a result, the heights of the optical ICs 14 can be aligned. That is, the upper surfaces of the optical ICs 14 and the wiring support 17 can be set on substantially the same horizontal plane. "Substantially the same horizontal plane" includes the same horizontal plane and includes a range of about 10 μm in the vertical direction.

[0037] <Effects> According to the multi-chip module of this embodiment, a package substrate on which multiple logic ICs are mounted is mounted (integrated) with a reinforcing fixing frame, and the logic ICs arranged on the outer periphery of the multi-chip module are optically connected by optical wiring. As a result, when transmitting data between logic ICs arranged on the outer periphery of the multi-chip module, the data can be transmitted directly by optical wiring without relaying it through logic ICs arranged on the inside of the multi-chip module. Consequently, data transmission latency can be reduced.

[0038] Further, a package substrate on which a plurality of logic ICs are mounted is mounted (integrated) by a reinforcing fixing frame, and opposing logic ICs between adjacent package substrates are electrically connected at a short distance via an electrical bridge wiring. Thereby, short-distance logic ICs can be connected with a simple configuration by the electrical bridge wiring, and cost can be reduced.

[0039] Further, data can be transmitted without traffic concentration on the logic IC arranged near the center of the package substrate. As a result, the latency of data transmission can be reduced.

[0040] <Method for Manufacturing Multi-Chip Module> A method for manufacturing the multi-chip module 10 according to the present embodiment will be described with reference to FIGS. 2A to 4B. FIGS. 2A, 3A, and 4A are schematic top views of the structure in each step. FIGS. 2B, 3B, and 4B show a side cross-sectional view of the structure in each step and the configuration of an optical wiring 16.

[0041] First, a logic IC 12, a photoelectric control IC 13, and a wiring pedestal 17 are mounted on a package substrate 11 (FIGS. 2A and 2B).

[0042] Next, a base portion 191 of the reinforcing fixing frame 19 is inserted (fitted) between opposing end faces of adjacently arranged package substrates 11, and the package substrates 11 and the reinforcing fixing frame 19 are fixed (secured). Thereby, a plurality of package substrates 11 can be integrated by aligning the positions of the photoelectric control ICs 13 and the wiring pedestals 17 in the horizontal direction and the vertical direction.

[0043] In the integration of the package substrates 11, the package substrates 11 and the reinforcing fixing frame 19 may be adhered to each other. Alternatively, a metal may be disposed on the periphery of the package substrates 11 and the contact surfaces of the reinforcing fixing frame 19 with the package substrates 11, and fixed by solder or the like.

[0044] Next, the electrical bridge wiring 18 is connected to the wiring pedestal 17 (FIGS. 3A and 3B).

[0045] Next, an optical IC 14 is integrated (mounted) on the photoelectric control IC 13.

[0046] Finally, the optical wiring 16 is connected to the optical IC 14 via the optical connection portion 15 (FIGS. 4A and 4B). Since the upper surfaces of the optical ICs 14 are arranged on substantially the same horizontal plane, the highly rigid optical wiring 16 can be used for optical connection with the connection portion in a state where the vertical tolerance is low.

[0047] As described above, the multi-chip module 10 in which a plurality of package substrates 11 mounted with a plurality of logic ICs 12 are integrated in a state where optical connection is completed can be manufactured.

[0048] <Effects> The effects of the multi-chip module 10 and the manufacturing method thereof according to the present embodiment will be described below.

[0049] First, for comparison, a conventional process of mounting a multi-chip module on a PCB 201 will be described with reference to FIGS. 5A to 5C.

[0050] First, after the logic IC 22, the photoelectric control IC 23, and the wiring pedestal 27 are mounted on the package substrate 21, the optical IC 24 is integrated (mounted) on the photoelectric control IC 23. These mountings are performed with high accuracy on the scale of C4 bumps (about 150 μm pitch).

[0051] Next, the package substrate 21 is mounted on the PCB 201 (FIG. 5A).

[0052] In the electrical connection portion 202 between the package substrate 21 and the PCB 201, for example, solder balls or the like arranged on the lower surface of the package substrate 21 are fabricated at a scale of about 1 mm pitch. This scale is larger than the scale of C4 bumps (about 150 μm pitch) in the electrical connection between the logic IC 22 and the package substrate 21. As described above, high positional accuracy is not required (positional accuracy is loose) in the electrical connection in the mounting process of the multi-chip module onto the PCB 201.

[0053] Next, the electrical bridge wiring 28 is connected with high accuracy onto the wiring pedestal 27 mounted on the package substrate 21 on the PCB 201 (FIG. 5B).

[0054] Finally, the optical IC 24 is connected to the optical wiring 26 using the optical connection portion 25 (FIG. 5C).

[0055] Thus, in the conventional method, logic ICs, photoelectric control ICs, wiring frames, and optical ICs are mounted on the package substrate with high precision, and after electrical connections are made between the package substrate and the PCB with loose positional accuracy, electrical and optical connections of the electrical bridge wiring, which require high precision, are then made again.

[0056] In this case, for example, it would be necessary to outsource the assembly process of logic ICs, photoelectric control ICs, wiring frames, and optical ICs to manufacturing company A, which possesses high-precision mounting technology, then outsource the less precise process (PCB mounting) to another manufacturing company B (a cost-competitive manufacturing company) at a lower cost, and finally outsource the optical connection process back to manufacturing company A. This would complicate the manufacturing process and increase manufacturing costs.

[0057] Furthermore, in conventional multi-chip modules, individual differences in the height of the electrical connection points on the package substrate and individual differences in the thickness of the package substrate are superimposed on the height of the optical IC and the wiring tray mounted on the package substrate on the PCB (the vertical position of the upper surface of the optical IC and the wiring tray). As a result, variations in the height of the optical IC and the wiring tray increase.

[0058] Furthermore, the height of each optical connection point on the optical IC (the vertical position on the upper surface of the optical connection point) is superimposed by individual differences in the height of the electrical connection points on the package substrate and individual differences in the height of the package substrate. As a result, the variation in the height of the optical connection points increases.

[0059] Furthermore, in the inclination of the optical IC, optical connector, and wiring stand (the inclination of the surfaces of the optical IC, optical connector, and wiring stand relative to the surface of the package substrate), individual differences in the inclination of the electrical connection part of the package substrate and individual differences in the inclination of the package substrate are superimposed. As a result, the variation in the inclination of the optical IC, optical connector, and wiring stand increases.

[0060] These factors make it difficult to align the optical IC, optical connector, and wiring frame using conventional methods. As a result, it is difficult to perform the optical connection process after mounting on the PCB.

[0061] Next, the process of mounting the multi-chip module 10 to the PCB 101 according to this embodiment, that is, the manufacturing process of the multi-chip module mounting substrate, will be described with reference to Figure 1B. Figure 1B shows a side cross-sectional view of the multi-chip module mounting substrate and the configuration of the optical wiring 16.

[0062] In a multi-chip module mounting board, the transmission and reception of optical signals between the multi-chip module 10 and an external environment including other multi-chip modules is performed via optical wiring 16, eliminating the need for a connection between the package board 11 and the PCB 101.

[0063] On the other hand, since the electrical connection to the power supply and external electrical signals is made via the PCB 101, the package substrate 11 is connected to the PCB 101 via the electrical connection part 102.

[0064] As described above, the multi-chip module 10 is manufactured by first mounting the logic IC 12, photoelectric control IC 13, optical IC 14, and wiring support frame 17 on the package substrate 11 with high positional accuracy on the scale of C4 bumps (approximately 150 μm pitch), followed by a process of optical connection between the package substrates 11, which requires high precision. Next, the multi-chip module 10 is mounted on the PCB 101 with a looser positional accuracy on the scale of approximately 1 mm pitch.

[0065] In this way, after the high-precision manufacturing process of the multi-chip module using the C4 bump scale mounting process and the optical connection process, the PCB mounting (electrical connection) process, which requires less precise positioning, is carried out, thus separating the processes that require high precision from those that do not.

[0066] This allows, for example, a manufacturing company A, which possesses high-precision mounting technology, to handle the manufacturing process of a multi-chip module, and then another manufacturing company B, which has cost competitiveness, to handle the less precise process (the PCB mounting process) at a lower cost. This reduces the cost of manufacturing multi-chip modules.

[0067] Furthermore, in the multi-chip module according to this embodiment, the bottom surface of the beam portion of the reinforcing fixing frame contacts the top surface of the package substrate, thereby aligning the vertical position of the mounting structure of each package substrate. As a result, the vertical positions of the optical IC, the optical connection portion, and the wiring frame can be aligned.

[0068] Furthermore, the side surface of the base of the reinforcing fixing frame contacts the end face of the package substrate, allowing the horizontal position of the mounting structure of each package substrate to be aligned. As a result, the horizontal positions of the optical IC, the optical connection part, and the wiring frame can be aligned.

[0069] Furthermore, variations in the tilt of the optical IC, optical connection section, and wiring frame can be suppressed.

[0070] These features enable easy optical connection between each package substrate. Furthermore, the optical connection process can be performed before mounting on the PCB.

[0071] According to this embodiment, in a multi-chip module, the upper surfaces of optical ICs can be arranged on substantially the same horizontal plane, and optical connections can be easily made with high precision in the optical ICs. Furthermore, the upper surfaces of the wiring racks can be arranged on substantially the same horizontal plane, and electrical connections can be easily made with high precision using electrical bridge wiring.

[0072] Furthermore, in multi-chip modules, the number of integrated logic ICs can be increased, and connections between each logic IC can be made with low latency.

[0073] Furthermore, in the manufacturing of multi-chip modules, the integration process of multiple package substrates, which requires high positional accuracy, can be separated from the mounting process on PCBs, which requires less precise positional accuracy.

[0074] <Second Embodiment> A multi-chip module according to the second embodiment of the present disclosure will be described with reference to Figures 6A and 6B.

[0075] <Configuration of the Multi-Chip Module> As shown in Figures 6A and 6B, the multi-chip module 30 according to this embodiment comprises a plurality of package substrates 11, a logic IC 12, photoelectric / electrical control ICs 331 and 332, an optical IC 14, an optical connection section 15, an optical wiring 16, an electrical bridge wiring 18, and a reinforcing fixing frame 19.

[0076] In the multi-chip module 30, the configuration of the multiple package substrates 11, the logic IC 12, the optical IC 14, the optical connection section 15, the optical wiring 16, the electrical bridge wiring 18, and the reinforcing fixing frame 19 is the same as in the first embodiment.

[0077] The photoelectric and electrical control ICs 331 and 332 are positioned on the peripheral edge of the logic IC 12, which is located on the outer periphery of the package substrate 11. For example, the photoelectric and electrical control ICs 331 and 332 may be positioned on the end face of the logic IC 12, or on the upper surface near the peripheral edge of the logic IC 12.

[0078] Of the photoelectric and electrical control ICs, the optical IC 14 is placed on the photoelectric and electrical control IC 331, which is located on the outer periphery of the multi-chip module 30.

[0079] Among the photoelectric and electrical control ICs, the electrical bridge wiring 18 is arranged (connected) on the photoelectric and electrical control IC 332, which is located on the end face (outer periphery) facing the end face (outer periphery) of the adjacent package substrate 11.

[0080] The photoelectric / electrical control IC 331, which is connected to the optical IC 14, drives the optical IC 14 based on the output signal from the logic IC 12. The photoelectric control IC 13 also amplifies the electrical signal converted from the optical signal by the optical IC 14 and outputs it to the logic IC 12.

[0081] Figure 7A shows a block diagram of the connection configuration between the optical IC 14 and the photoelectric / electrical control IC 331.

[0082] The optical IC 14 includes an optical modulation element 141 and a light receiving element 142.

[0083] The photoelectric / electrical control IC 331 includes a transmit amplifier circuit 333 and a transmit variable resistor 334 on the transmitting side to the optical IC 14. The resistance value of the transmit variable resistor 334 is set by a setting signal to achieve impedance matching to the input impedance of the optical modulation element 141.

[0084] Furthermore, the photoelectric / electrical control IC 331 includes a receiving amplifier circuit 335 and a receiving variable resistor 336 on the receiving side from the optical IC 14. The resistance value of the receiving variable resistor 336 is set by a setting signal to match the capacitance and bandwidth of the light-receiving element 142.

[0085] This configuration allows electrical signals to be transmitted and received at high frequency between package substrates 11 via the optical IC 14 and the photoelectric / electrical control IC 331.

[0086] Furthermore, the photoelectric / electrical control IC 332, to which the electrical bridge wiring 18 is connected, transmits the output signal from the logic IC 12 to the adjacent logic IC 12 on the package board 11 via the electrical bridge wiring 18. In addition, the photoelectric / electrical control IC 332 amplifies the electrical signal from the electrical bridge wiring 18 and outputs it to the logic IC 12.

[0087] Figure 7B shows a block diagram of the connection configuration between the electrical bridge wiring 18 and the photoelectric / electrical control IC 332.

[0088] The electrical bridge wiring 18 is composed of electrical wiring. The photoelectric / electrical control IC 332 to which the electrical bridge wiring 18 is connected includes a transmitting amplifier circuit 333 and a transmitting variable resistor 334 on the transmitting side to the electrical bridge wiring 18. It also includes a receiving amplifier circuit 335 and a receiving variable resistor 336 on the receiving side from the electrical bridge wiring 18.

[0089] In the photoelectric / electrical control IC 332, the resistance values ​​of the transmitting variable resistor 334 and the receiving variable resistor 336 are set by a setting signal so as to achieve impedance matching to the characteristic impedance of the electrical wiring formed in the electrical bridge wiring 18.

[0090] This configuration allows electrical signals to be transmitted and received at high frequency between package substrates 11 via the electrical bridge wiring 18 and the photoelectric / electrical control IC 332.

[0091] Thus, the same optical / electric variable drive / amplifier IC can be used to drive signals and amplify signals for both electrical bridge wiring and optical ICs.

[0092] According to this embodiment of the multi-chip module, a package substrate on which multiple logic ICs are mounted is integrated using a reinforcing fixing frame, and the logic ICs arranged on the outer periphery of the multi-chip module are optically connected by optical wiring. As a result, when transmitting data between logic ICs arranged on the outer periphery of the multi-chip module, the data can be transmitted directly by optical wiring without relaying it through logic ICs arranged on the inside of the multi-chip module. Consequently, data transmission latency can be reduced.

[0093] Furthermore, package boards equipped with multiple logic ICs are mounted (integrated) using a reinforcing fixing frame, and opposing logic ICs between adjacent package boards are electrically connected via short-distance electrical bridge wiring. This allows for simple connections between short-distance logic ICs using electrical bridge wiring, thereby reducing costs.

[0094] Furthermore, data can be transmitted without traffic concentrating on the logic IC located near the center of the package substrate. As a result, data transmission latency can be reduced.

[0095] Furthermore, in the multi-chip module according to this embodiment, a photoelectric / electrical control IC is used instead of the photoelectric control IC 13 and wiring frame in the first embodiment, thus reducing the number of components.

[0096] <Manufacturing Method for Multi-Chip Modules> The manufacturing method for the multi-chip module 30 according to this embodiment will be described with reference to Figures 8A to 10B. Figures 8A, 9A, and 10A show schematic top views of the structure in each process. Figures 8B, 9B, and 10B show side cross-sectional views of the structure in each process and the configuration of the optical wiring 16.

[0097] First, the logic IC 12 and the photoelectric / electrical control ICs 331 and 332 are mounted on the package substrate 11 (Figures 8A and 8B).

[0098] Next, the base 191 of the reinforcing fixing frame 19 is inserted (fitted) between the opposing end faces of the adjacent package substrates 11, thereby fixing (securing) the package substrates 11 and the reinforcing fixing frame 19. This allows multiple package substrates 11 to be integrated with the photoelectric / electrical control ICs 331 and 332 aligned in both the horizontal and vertical directions.

[0099] In the assembly of the package substrate 11, the package substrate 11 and the reinforcing fixing frame 19 may be bonded together. Alternatively, metal may be placed around the package substrate 11 and on the contact surface of the reinforcing fixing frame 19 with the package substrate 11, and then fixed in place with solder or the like.

[0100] Next, the electrical bridge wiring 18 is connected to the photoelectric / electrical control IC 332 (Figures 9A and 9B).

[0101] Next, the optical IC 14 is integrated (mounted) on the photoelectric / electrical control IC 331.

[0102] Finally, the optical wiring 16 is connected to the optical IC 14 via the optical connection section 15 (Figures 10A and 10B). Since the upper surfaces of the optical IC 14 are arranged on approximately the same horizontal plane, the optical connection to the connection section can be made using the highly rigid optical wiring 16 with low vertical tolerance.

[0103] Based on the above, it is possible to manufacture a multi-chip module 30 in which multiple package substrates 11 on which multiple logic ICs 12 are mounted are integrated with optical connections completed.

[0104] In the manufacturing method of the multi-chip module according to this embodiment, similar to the first embodiment, processes requiring high precision and processes requiring less precision can be separated. This makes it possible to reduce the cost of manufacturing the multi-chip module.

[0105] According to this embodiment, in a multi-chip module, the top surfaces of optical ICs can be arranged on substantially the same horizontal plane, and optical connections can be easily made with high precision in the optical ICs. Furthermore, the top surfaces of photoelectric and electrical control ICs can be arranged on substantially the same horizontal plane, and electrical connections can be easily made with high precision using electrical bridge wiring.

[0106] Furthermore, in multi-chip modules, the number of integrated logic ICs can be increased, and connections between each logic IC can be made with low latency.

[0107] Furthermore, in the manufacturing of multi-chip modules, the integration process of multiple package substrates, which requires high positional accuracy, can be separated from the mounting process on PCBs, which requires less precise positional accuracy.

[0108] The multi-chip module according to the embodiments of this disclosure may be used in communication devices. Alternatively, it may be used in devices such as arithmetic units, computing devices (computers), and signal processing devices. A device equipped with the multi-chip module according to these embodiments may be used in a data center. Multiple devices may be connected to form a network.

[0109] In the embodiments of this disclosure, an example is shown in which nine logic ICs are arranged on the package substrate, but the number of logic ICs is not limited to this, and multiple logic ICs may be arranged.

[0110] In the embodiments described herein, examples of the structure, dimensions, materials, etc., of each component in the configuration and manufacturing method of a multi-chip module are shown, but the invention is not limited thereto. Any configuration that allows the multi-chip module to perform its function and achieve its intended effect is acceptable.

[0111] It should be noted that this disclosure is not limited to the embodiments described above, and it is evident that many modifications and combinations are possible within the technical concept of this disclosure by a person with ordinary skill in the art.

[0112] Some or all of the embodiments described above, or examples thereof, may also be described as follows, but are not limited to these.

[0113] (Note 1) A multichip module comprising: a plurality of package substrates arranged horizontally; a plurality of logic ICs arranged on the package substrates; a photoelectric control IC arranged on the peripheral edge of the plurality of logic ICs, which is located on the outer periphery of the multichip module; an optical IC arranged on the photoelectric control IC; an optical connection portion arranged on the optical IC; optical wiring connected to the optical connection portion; a wiring frame arranged on the peripheral edge of the plurality of logic ICs, which is located on the peripheral edge of an adjacent logic IC arranged on the package substrate; an electrical bridge wiring connected to the wiring frame; and a reinforcing fixing frame for fixing the plurality of package substrates.

[0114] (Note 2) The multichip module according to Note 1, wherein, among the plurality of package substrates, one wiring frame on one of the package substrates and another wiring frame on another of the package substrates are connected via the electrical bridge wiring, and among the plurality of package substrates, one optical connection portion on one of the package substrates and another optical connection portion on another of the package substrates are connected via the optical wiring.

[0115] (Note 3) A multi-chip module comprising: a plurality of package substrates arranged horizontally; a plurality of logic ICs arranged on the package substrates; photoelectric / electrical control ICs arranged on the peripheral edges of the logic ICs, which are located on the outer periphery of the package substrates; an optical IC arranged on the photoelectric / electrical control ICs located on the outer periphery of the multi-chip module; an optical connection portion arranged on the optical IC; an optical wiring connected to the optical connection portion; an electrical bridge wiring connected to the photoelectric / electrical control ICs located on the peripheral edges of the logic ICs, which are facing the peripheral edges of the logic ICs arranged on adjacent package substrates; and a reinforcing fixing frame for fixing the plurality of package substrates.

[0116] (Note 4) The multichip module according to Note 3, wherein, among the plurality of package substrates, one photoelectric / electric control IC on one of the package substrates and another photoelectric / electric control IC on another of the package substrates are connected via the electrical bridge wiring, and among the plurality of package substrates, one optical connection portion on one of the package substrates and another optical connection portion on another of the package substrates are connected via the optical wiring.

[0117] (Note 5) The multichip module according to Note 1 or Note 3, wherein the reinforcing fixing frame comprises a base and a beam, the base extending perpendicularly to the upper surface of the package substrate and positioned between opposing end faces of adjacent package substrates, and the beam being provided at one end of the base, extending perpendicularly to the end face, and positioned so that the bottom surface of the beam abuts the upper surface of the package substrate.

[0118] (Note 6) An apparatus comprising the multi-chip module described in Note 1 or Note 2.

[0119] (Note 7) A data center equipped with the devices described in Note 6.

[0120] (Note 8) A method for manufacturing a multi-chip module mounting board for a printed circuit board, comprising the steps of: mounting a plurality of logic ICs on a package board; mounting either a photoelectric control IC or a photoelectric / electrical control IC on the peripheral edge of the plurality of logic ICs that is arranged on the outer periphery of the multi-chip module; and mounting either a wiring frame or a photoelectric / electrical control IC on the peripheral edge of the plurality of logic ICs that is facing the peripheral edge of an adjacent logic IC arranged on the package board. A method for manufacturing a multi-chip module mounting substrate, comprising: the steps of: fixing a plurality of the package substrates via a reinforcing fixing frame; connecting an electrical bridge wiring to either the wiring frame or the photoelectric / electrical control IC; mounting an optical IC on either the photoelectric control IC or the photoelectric / electrical control IC; mounting an optical connection part on the optical IC; connecting an optical wiring to the optical connection part; and mounting the plurality of package substrates fixed via the reinforcing fixing frame onto the printed circuit board.

[0121] (Note 9) The multi-chip module described in Note 5, wherein the height of the wiring support frame is greater than the thickness of the beam.

[0122] (Note 10) The multi-chip module described in Note 5, wherein the height of the photoelectric / electrical control IC is greater than the thickness of the beam portion.

[0123] (Note 11) The multi-chip module described in Notes 1, 2, 5, and 9, wherein the photoelectric control IC drives the optical IC based on a signal from the logic IC, converts the signal from the optical IC into an electrical signal, amplifies it, and outputs it to the logic IC.

[0124] (Note 12) The multi-chip module according to Notes 3, 4, 5, and 10, wherein the photoelectric / electrical control IC, which is located on the peripheral edge of a logic IC and facing the peripheral edge of a logic IC located on an adjacent package substrate, includes a variable resistor that impedance matches with the electrical bridge wiring.

[0125] (Note 13) The multi-chip module according to Notes 3, 4, 5, 10, and 12, wherein the photoelectric / electrical control IC arranged on the outer periphery of the multi-chip module drives the optical IC based on a signal from the logic IC, converts the signal from the optical IC into an electrical signal, amplifies it, and outputs it to the logic IC, and the photoelectric / electrical control IC arranged on the peripheral edge of the logic IC, facing the peripheral edge of the logic IC arranged on the adjacent package substrate, amplifies the signal transmitted and received with the adjacent logic IC arranged on the package substrate via the electrical bridge wiring.

[0126] This disclosure relates to a multichip module and a method for manufacturing the same, and can be applied to communication devices, computing devices, computers, signal processing devices, and the like.

[0127] 10 Multi-chip module 11 Package substrate 12 Logic IC 13 Photoelectric control IC 14 Optical IC 15 Optical connection section 16 Optical wiring 17 Wiring frame 18 Electrical bridge wiring 19 Reinforcement fixing frame

Claims

1. A multi-chip module comprising: a plurality of package substrates arranged horizontally; a plurality of logic ICs arranged on the package substrates; a photoelectric control IC arranged on the peripheral edge of the plurality of logic ICs, which is located on the outer periphery of the multi-chip module; an optical IC arranged on the photoelectric control IC; an optical connection portion arranged on the optical IC; optical wiring connected to the optical connection portion; a wiring frame arranged on the peripheral edge of the plurality of logic ICs, which is located on the peripheral edge of an adjacent logic IC on the package substrate; electrical bridge wiring connected to the wiring frame; and a reinforcing fixing frame for fixing the plurality of package substrates.

2. The multichip module according to claim 1, wherein, among the plurality of package substrates, one wiring frame on one of the package substrates and another wiring frame on another of the package substrates are connected via the electrical bridge wiring, and among the plurality of package substrates, one optical connection portion on one of the package substrates and another optical connection portion on another of the package substrates are connected via the optical wiring.

3. A multi-chip module comprising: a plurality of package substrates arranged horizontally; a plurality of logic ICs arranged on the package substrates; photoelectric / electrical control ICs arranged on the peripheral edges of the logic ICs, specifically on the outer periphery of the package substrates; an optical IC arranged on the photoelectric / electrical control ICs arranged on the outer periphery of the multi-chip module; an optical connection portion arranged on the optical IC; an optical wiring connected to the optical connection portion; an electrical bridge wiring connected to the photoelectric / electrical control ICs arranged on the peripheral edges of the logic ICs, facing the peripheral edges of the logic ICs arranged on adjacent package substrates; and a reinforcing fixing frame for fixing the plurality of package substrates.

4. The multichip module according to claim 3, wherein, among the plurality of package substrates, one photoelectric / electric control IC on one of the package substrates and another photoelectric / electric control IC on another of the package substrates are connected via the electrical bridge wiring, and among the plurality of package substrates, one optical connection portion on one of the package substrates and another optical connection portion on another of the package substrates are connected via the optical wiring.

5. The multi-chip module according to claim 1 or claim 3, wherein the reinforcing fixing frame comprises a base portion and a beam portion, the base portion extending perpendicularly to the upper surface of the package substrate and positioned between opposing end faces of adjacent package substrates, and the beam portion provided at one end of the base portion, extending perpendicularly to the end face, and positioned so that the bottom surface of the beam portion abuts against the upper surface of the package substrate.

6. An apparatus comprising the multi-chip module described in claim 1 or claim 3.

7. A data center comprising the apparatus described in claim 6.

8. A method for manufacturing a multi-chip module mounting substrate for a printed circuit board, comprising: mounting a plurality of logic ICs on a package substrate; mounting either a photoelectric control IC or a photoelectric / electrical control IC on the peripheral edge of the plurality of logic ICs that is arranged on the outer periphery of the multi-chip module; mounting either a wiring frame or a photoelectric / electrical control IC on the peripheral edge of the plurality of logic ICs that is facing the peripheral edge of an adjacent logic IC arranged on the package substrate; fixing the plurality of package substrates via a reinforcing fixing frame; connecting an electrical bridge wiring to either the wiring frame or the photoelectric / electrical control IC; mounting an optical IC on either the photoelectric control IC or the photoelectric / electrical control IC; mounting an optical connection part on the optical IC; and connecting optical wiring to the optical connection part. A method for manufacturing a multi-chip module mounting board, comprising the steps of: next, mounting the plurality of package substrates, which are fixed via the reinforcing fixing frame, onto the printed circuit board.

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