Optical module

Abstract

To provide a new and improved optical module that can reduce problems that occur in configurations where optical semiconductor elements are flip-chip mounted to a substrate.SOLUTION: An optical module includes, for example, a substrate and an optical semiconductor element flip-chip mounted on the substrate, and the substrate is provided with an opening that passes through the substrate in the thickness direction at least at a position overlapping with the optical semiconductor element. The opening may be a notch provided in the edge of the substrate. The optical semiconductor element may be provided with an alignment marker that is visible through an opening from the opposite side of the substrate from the optical semiconductor element and is used for alignment with a component other than the optical semiconductor element. Further, the optical semiconductor element may output or receive light in a direction along the surface of the substrate on which the optical semiconductor element is mounted.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to an optical module.

Background Art

[0002] Conventionally, an optical module in which an optical semiconductor element is flip-chip mounted on a substrate has been known (for example, Patent Document 1). The optical semiconductor element is, for example, a modulator or a coherent mixer.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Flip-chip mounting has an advantage that, compared with wire bonding mounting, transmission loss for higher frequency signals can be reduced because impedance matching is easier.

[0005] However, when actually flip-chip mounting an optical semiconductor element on a substrate, various problems may occur, such as an increase in stress due to heat, interference with other components, misalignment with other components, and increase in size.

[0006] Therefore, one of the problems of the present invention is to obtain a new and improved optical module capable of reducing problems occurring in a configuration in which an optical semiconductor element is flip-chip mounted on a substrate.

Means for Solving the Problems

[0007] The optical module of the present invention comprises, for example, a substrate and an optical semiconductor element mounted on the substrate in a flip-chip configuration, wherein the substrate is provided with an opening that penetrates through the substrate in the thickness direction at a position that overlaps with the optical semiconductor element.

[0008] In the optical module, the aperture may be a notch provided at the edge of the substrate.

[0009] In the optical module, the optical semiconductor element may be provided with an alignment marker that is visible from the opposite side of the substrate from the optical semiconductor element through the aperture, and is used for aligning with a component other than the optical semiconductor element.

[0010] In the optical module, the optical semiconductor element may output or receive light in a direction along the surface of the substrate on which the optical semiconductor element is mounted.

[0011] The optical module may include optical components that are partially housed in the aperture and through which light output or received by the optical semiconductor element passes.

[0012] The optical module may include components partially housed in the aperture.

[0013] In the optical module, the substrate may have a plurality of electrodes electrically connected to the conductor of the optical semiconductor element along the edge of the aperture.

[0014] In the optical module described above, the aperture is a notch provided at the edge of the substrate, the substrate has a first edge as the edge of the notch, which is separated from the edge, and a second edge which extends between the first edge and the edge, and the plurality of electrodes may include a plurality of first electrodes provided along the first edge.

[0015] In the optical module, the substrate may have a plurality of second electrodes provided along the second edge as the plurality of electrodes.

[0016] In the optical module, a signal having a higher frequency than that of the second electrode may be transmitted at the first electrode.

[0017] The optical module may include a semiconductor element mounted on the substrate, located on the side opposite to the edge with respect to the optical semiconductor element, and having a conductor electrically connected to the electrode through a conductor wiring provided on the substrate.

[0018] In the optical module, a recess or a protrusion may be provided at the edge of the opening.

[0019] The optical module may include a cooling mechanism provided on the side opposite to the substrate with respect to the optical semiconductor element and cooling the optical semiconductor element.

[0020] The optical module may include a heat transfer member provided on the side opposite to the substrate with respect to the optical semiconductor element and transferring heat from the optical semiconductor element to the side opposite to the optical semiconductor element.

[0021] The optical module may include a housing that houses the substrate and the optical semiconductor element.

[0022] In the optical module, a part of the housing may be provided on the side opposite to the substrate with respect to the optical semiconductor element and function as a heat transfer member that transfers heat from the optical semiconductor element to the side opposite to the optical semiconductor element.

[0023] In the optical module, underfill may not be provided between the substrate and the optical semiconductor element.

Advantages of the Invention

[0024] According to the present invention, for example, an improved and novel optical module capable of reducing problems occurring in a configuration in which an optical semiconductor element is flip-chip mounted on a substrate can be obtained.

Brief Description of the Drawings

[0025] [Figure 1] FIG. 1 is an exemplary and schematic side view (partial cross-sectional view) showing the internal configuration of the optical module according to the first embodiment. [Figure 2] FIG. 2 is an exemplary and schematic plan view of the substrate according to the first embodiment in which the optical semiconductor element is flip-chip mounted. [Figure 3] FIG. 3 is an exemplary and schematic plan view of the substrate according to the second embodiment in which the optical semiconductor element is flip-chip mounted. [Figure 4] FIG. 4 is an exemplary and schematic plan view of the substrate according to the third embodiment in which the optical semiconductor element is flip-chip mounted. [Embodiments for Carrying Out the Invention]

[0026] Exemplary embodiments of the present invention are disclosed below. The configurations of the embodiments shown below, as well as the operations and results (effects) brought about by such configurations, are examples. The present invention can also be realized by configurations other than those disclosed in the following embodiments. Further, according to the present invention, it is possible to obtain at least one of various effects (including derivative effects) obtained by the configuration.

[0027] The plurality of embodiments shown below have similar configurations. Therefore, according to the configurations of each embodiment, similar operations and effects based on such similar configurations can be obtained. Further, in the following, the same reference numerals are given to those similar configurations, and redundant descriptions may be omitted.

[0028] In this specification, ordinal numbers are given for convenience in distinguishing members, parts, directions, etc., and do not indicate priorities or orders.

[0029] Also, in each figure, the X direction is represented by arrow X, the Y direction is represented by arrow Y, and the Z direction is represented by arrow Z. The X direction, Y direction, and Z direction intersect each other and are perpendicular to each other.

[0030] [First Embodiment] Figure 1 is a side view showing the internal configuration of the optical module 100 according to the first embodiment. The optical module 100 has a configuration similar to, for example, the optical module disclosed in PCT / JP2021 / 002326 (WO-A1-2021 / 153462).

[0031] As shown in Figure 1, the optical module 100 comprises a housing 10, a feedthrough 21, and a substrate 22A (22).

[0032] The enclosure 10 has a bottom wall 10a, a perimeter wall 10b, and a top wall 10c. The bottom wall 10a has a roughly rectangular and plate-like shape. The bottom wall 10a intersects with the Z direction and extends approximately perpendicularly, and extends approximately along the X and Y directions. The perimeter wall 10b extends from the edge of the bottom wall 10a with a roughly constant thickness and extends approximately along the Z direction. The perimeter wall 10b may also be called a side wall. The top wall 10c has a roughly rectangular and plate-like shape. The top wall 10c also intersects with the Z direction and extends approximately perpendicularly, and extends approximately along the X and Y directions.

[0033] The peripheral wall 10b is provided with a window member 10d that transmits light between the inside (housing chamber S) and the outside of the housing 10. Within the housing 10, light is transmitted from inside the housing 10 to the outside, light is incident on the housing 10 from the outside, and light is transmitted through devices and components inside the housing 10.

[0034] The bottom wall 10a is made of a material with high thermal conductivity, such as copper tungsten (CuW), copper molybdenum (CuMo), or aluminum oxide (Al2O3). The peripheral wall 10b and the top wall 10c are made of a material with a low coefficient of thermal expansion, such as Fe-Ni-Co alloy or aluminum oxide (Al2O3).

[0035] The periphery of the top wall 10c, also called the lid, overlaps with the Z-direction edge of the peripheral wall 10b in the Z-direction. By joining the periphery of the top wall 10c and the Z-direction edge of the peripheral wall 10b, a housing chamber S for accommodating components and devices is formed within the housing 10. A gas, such as an inert gas or air, is contained within the housing chamber S (within the housing 10). The housing chamber S may be hermetically sealed.

[0036] The feedthrough 21 has a conductor 21a and an insulating portion, and penetrates a portion of the peripheral wall 10b of the housing 10. The conductor 21a of the feedthrough 21 is made of a highly conductive metallic material, such as a copper-based metal material. The insulating portion of the feedthrough 21 is made of an insulator, such as a ceramic. The boundary between the feedthrough 21 and the housing 10 is insulated and hermetically sealed, for example.

[0037] The substrate 22A(22) extends from a position away from the bottom wall 10a of the housing 10 in the Z direction, intersecting and substantially perpendicular to the Z direction, and extending substantially along the X and Y directions. The substrate 22 has a surface 22a located at the end in the Z direction and a surface 22b located at the end in the opposite direction to the Z direction. Surface 22a faces the Z direction, intersects and substantially perpendicular to the Z direction, and extends substantially along the X and Y directions. On the other hand, surface 22b faces the opposite direction to the Z direction, intersects and substantially perpendicular to the Z direction, and extends substantially along the X and Y directions. The Z direction is an example of the thickness direction of the substrate 22.

[0038] The substrate 22 has an insulator and a conductor. The insulator is made of, for example, ceramic. The conductor is made of a highly conductive metallic material such as a copper-based metal material. The substrate 22 includes electrodes 22c and wiring 22d as conductors. Although Figure 1 shows only conductors provided on surface 22b of the substrate 22, conductors may also be provided inside the substrate 22 or on surface 22a.

[0039] On surface 22b of the substrate 22, the semiconductor element 31 and the optical semiconductor element 32 are mounted using a flip-chip mounting method. That is, the semiconductor element 31 and the optical semiconductor element 32 are located between the substrate 22 and the bottom wall 10a. Surface 22b may also be referred to as the mounting surface. In this embodiment, no underfill is provided, at least between the optical semiconductor element 32 and the substrate 22.

[0040] The semiconductor element 31 is, for example, a modulator driver or a transimpedance amplifier. The optoelectronic semiconductor element 32 is, for example, a modulator or a coherent mixer.

[0041] The conductors of substrate 22 electrically connect the conductors of semiconductor element 31 and the conductors of optoelectronic semiconductor element 32. Furthermore, the conductors of substrate 22 electrically connect the conductor 21a of feedthrough 21 and the conductors of semiconductor element 31. Substrate 22 may also be referred to as an interface substrate.

[0042] On the side of the semiconductor element 31 opposite the substrate 22, a thermal conductive sheet 41 and a heat transfer block 42 are provided. The thermal conductive sheet 41 and the heat transfer block 42 are interposed between the semiconductor element 31 and the bottom wall 10a of the housing 10. The thermal conductive sheet 41 is also interposed between the semiconductor element 31 and the heat transfer block 42. The thermal conductive sheet 41 is flexible. The heat transfer block 42 is interposed between the thermal conductive sheet 41 and the bottom wall 10a. The heat transfer block 42 is made of a highly thermally conductive metal material, such as a copper-based metal material. Furthermore, a heat sink 50 with fins is provided on the outside of the housing 10 on the side of the bottom wall 10a opposite the heat transfer block 42. The heat sink 50 is made of a highly thermally conductive metal material, such as an aluminum-based metal material. In this configuration, the heat generated in the semiconductor element 31 is released to the outside of the housing 10 via the thermal conductive sheet 41, the heat transfer block 42, the bottom wall 10a (housing 10), and the heat sink 50. These thermal conductive sheet 41, heat transfer block 42, bottom wall 10a, and heat sink 50 are examples of heat transfer members.

[0043] On the other hand, a TEC43 (thermoelectric cooler) is provided on the side of the optical semiconductor element 32 opposite to the substrate 22. The TEC43 is an example of a cooling mechanism. The TEC43 is interposed between the optical semiconductor element 32 and the bottom wall 10a. In addition, a heat sink 50 is provided on the outside of the housing 10 on the side of the bottom wall 10a opposite to the TEC43. In this configuration, the heat generated in the optical semiconductor element 32 is released to the outside of the housing 10 via the TEC43, the bottom wall 10a (housing 10), and the heat sink 50. These TEC43, bottom wall 10a, and heat sink 50 are examples of heat transfer members. Note that a thermal conductive sheet may be interposed as a heat transfer member between the TEC43 and the optical semiconductor element 32, and between the TEC43 and the bottom wall 10a.

[0044] For example, optical components 33 and light-emitting units 34 are provided on the bottom wall 10a.

[0045] The optical component 33 is attached to the bottom wall 10a, for example, via adhesive or the like. The optical component 33 is, for example, a lens, mirror, beam combiner, beam splitter, optical isolator, etc. The optical component 33 is just one example of a component. The optical component 33 may also be attached to the bottom wall 10a via another member.

[0046] The light-emitting unit 34 is, for example, a chip-on submount. The chip-on submount has a submount and a light-emitting element, such as a semiconductor laser element, mounted on the submount. A separate TEC43 is interposed between the light-emitting unit 34 and the bottom wall 10a, in addition to the TEC43 corresponding to the optical semiconductor element 32. The light-emitting unit 34 may have a case, and the chip-on submount may be housed within this case.

[0047] A portion of the feedthrough 21, the substrate 22, the semiconductor element 31, the optoelectronic element 32, the optical component 33, the light-emitting unit 34, the heat conductive sheet 41, the heat transfer block 42, and the TEC 43 are housed inside the housing 10, i.e., inside the housing chamber S. Electrical components, such as capacitors and wiring boards, may also be housed inside the housing 10. Electrical components are just one example of the components.

[0048] [Circuit board configuration] Figure 2 is a plan view of the substrate 22A(22) on which the semiconductor element 31 and the optical semiconductor element 32 are flip-chip mounted, as viewed in the opposite direction to the Z direction. As shown in Figure 2, the semiconductor element 31 and the optical semiconductor element 32 are aligned in the X direction.

[0049] The substrate 22 illustrated in Figure 2 has, for example, an optical semiconductor element 32 that outputs or receives light, and a semiconductor element 31 corresponding to the optical semiconductor element 32 mounted on it using a flip-chip mounting system. Specifically, if an optical semiconductor element 32 that outputs light, such as a modulator, is mounted on the substrate 22, then a semiconductor element 31, such as a modulator driver, is mounted on the substrate 22. Also, if an optical semiconductor element 32 that receives light, such as a coherent mixer, is mounted on the substrate 22, then a semiconductor element 31, such as a transimpedance amplifier, is mounted on the substrate 22. However, the substrate 22 may also have an optical semiconductor element 32 that outputs light, a semiconductor element 31 corresponding to the optical semiconductor element 32 that outputs light, an optical semiconductor element 32 that receives light, and a semiconductor element 31 corresponding to the optical semiconductor element 32 that receives light mounted on it.

[0050] Furthermore, as shown in Figures 2 and 1, an opening 22f is provided in the substrate 22. The opening 22f penetrates the substrate 22 in the thickness direction (Z direction) at least at a position overlapping with the optical semiconductor element 32.

[0051] In this embodiment, as an example, the opening 22f is a notch cut out in the edge 22e located at the X-direction end of the substrate 22, so as to be recessed in the opposite direction to the X-direction.

[0052] As shown in Figure 2, the optical semiconductor element 32 is provided with an alignment marker 32b that is visible from the substrate 22 on the side opposite to the optical semiconductor element 32 through an aperture 22f. The alignment marker 32b is provided on the surface 32a located at the Z-direction end of the optical semiconductor element 32, that is, on the mounting surface where electrodes (not shown) are provided and which faces the surface 22b of the substrate 22, and is provided in the region of the surface 32a that overlaps with the aperture 22f in the Z-direction.

[0053] The alignment marker 32b may be used to align the optical semiconductor element 32 with other components, such as the optical component 33. However, it is not limited to this, and the alignment marker 32b may also be used to align the substrate 22 on which the optical semiconductor element 32 is mounted, i.e., the substrate assembly in which the optical semiconductor element 32, the semiconductor element 31, and the substrate 22 are integrated, with the housing 10 or other components.

[0054] Furthermore, the alignment markers 32b may be provided at multiple locations. By providing alignment markers 32b at multiple locations in this way, it becomes easier to understand the orientation and optical axis direction of the optical semiconductor element 32.

[0055] Furthermore, the alignment marker 32b may have a portion extending in a predetermined direction (in this case, the X direction), as in the case of a linear alignment marker 32b1, or it may have portions extending in two directions that intersect each other and are substantially orthogonal, as in the case of a cross-shaped alignment marker 32b2. In this way, having a portion extending in a predetermined direction on the alignment marker 32b makes it easier to grasp the orientation and optical axis direction of the optical semiconductor element 32. Note that the position, shape, size, number, and other specifications of the alignment marker 32b are not limited to the example in Figure 2.

[0056] Furthermore, in this embodiment, if the optical semiconductor element 32 is an element that outputs light, the direction in which the output light propagates is the X direction, and if the optical semiconductor element 32 is an element that receives light, the direction in which the received light propagates is the opposite direction to the X direction. Both the X direction and the opposite direction to the X direction are directions along the surface 22b of the substrate 22, that is, the surface 22b on which the optical semiconductor element 32 and the semiconductor element 31 are mounted on the substrate 22. The X direction or the opposite direction to the X direction may also be referred to as the optical axis direction.

[0057] Here, as shown in Figures 2 and 1, in this embodiment, the optical component 33 is partially housed within the aperture 22f. This allows the optical component 33 to be closer to the optical semiconductor element 32 compared to when the optical component 33 is located outside the aperture 22f, i.e., further in the X direction than the edge 22e of the substrate 22. With this configuration, the area of ​​the region in the optical module 100 where the substrate 22 and the optical component 33 are provided can be made smaller, and consequently the optical module 100 can be made smaller. Note that a similar effect can be obtained even if a component other than the optical component 33, such as an electrical component, is partially housed within the aperture 22f instead of the optical component 33.

[0058] Furthermore, if the optical component 33 is an optical component through which the light output or received by the optical semiconductor element 32 passes, and the optical component 33 is located outside the aperture 22f, there may be disadvantages due to optical factors compared to the case where the optical component 33 is partially housed within the aperture 22f. Specifically, for example, if the optical component 33 is a collimating lens that collimates the light output by the optical semiconductor element 32, or a focusing lens that focuses the light received by the optical semiconductor element 32, the greater the distance between the optical component 33 and the optical semiconductor element 32 in the X direction, the greater the focal length of the optical component 33 must be set. In that case, there is a risk that the optical component 33 will become larger, and consequently the optical module 100 will become larger, and there is also a risk that the width of the collimated light that collimates the output light due to the optical component 33 will become larger. In this respect, in this embodiment, the optical component 33 is partially housed within the aperture 22f, and the distance between the optical semiconductor element 32 and the optical component 33 can be set to be shorter. Therefore, the undesirable events described above caused by optical factors resulting from a large distance between the optical semiconductor element 32 and the optical component 33 can be avoided.

[0059] Furthermore, as shown in Figure 2, the substrate 22 is provided with a plurality of electrodes 22c along the edges 22f1 and 22f2 of the opening 22f. Each electrode 22c is provided on the surface 22b of the substrate 22 and is electrically connected to the electrodes (not shown) of the optical semiconductor element 32 as conductors via connecting parts (not shown) such as solder bumps (solder balls).

[0060] The edge 22f1 of the opening 22f extends substantially along the Y direction at a position away from the edge 22e of the substrate 22. The edge 22f2 extends substantially along the X direction between the end of edge 22f1 and the edge 22e.

[0061] Multiple electrodes 22c1 arranged along the edge 22f1 are electrically connected to the conductor (not shown) of the semiconductor element 31 via wiring 22d provided on the substrate 22 and another electrode 22c (see Figure 1) adjacent to the semiconductor element 31. Relatively high-frequency signals are transmitted between the conductor of the optical semiconductor element 32 and the conductor of the semiconductor element 31 via these electrodes 22c1, wiring 22d, and other electrodes 22c. These signals are, for example, communication signals that transmit information. In a layout where the semiconductor element 31 and the optical semiconductor element 32 are aligned in the X direction, the electrodes 22c1 are located between the semiconductor element 31 and the optical semiconductor element 32, so the length of the electrical signal path via electrodes 22c1, wiring 22d, and other electrodes 22c can be made relatively short. Therefore, according to this embodiment, transmission loss of higher-frequency signals can be suppressed. Edge 22f1 is an example of a first edge, and electrode 22c1 is an example of a first electrode. Wiring 22d is an example of conductor wiring.

[0062] On the other hand, multiple electrodes 22c2 arranged along the edge 22f2 are also electrically connected to the conductor (not shown) of the semiconductor element 31 via wiring 22d provided on the substrate 22 and another electrode 22c (see Figure 1) adjacent to the semiconductor element 31. However, relatively low-frequency signals are transmitted between the conductor of the optical semiconductor element 32 and the conductor of the semiconductor element 31 via these electrodes 22c2, wiring 22d, and other electrodes 22c. These signals include, for example, power to activate the active layer, power to heat the heater, and detection signals from sensors. In a layout where the semiconductor element 31 and the optical semiconductor element 32 are aligned in the X direction, the electrodes 22c2 are located away from the space between the semiconductor element 31 and the optical semiconductor element 32, so the length of the electrical signal path via electrodes 22c2, wiring 22d, and other electrodes 22c becomes relatively long. However, for the transmission of relatively low-frequency signals and power, the length can be kept to a level that does not cause any particular problems. Edge 22f2 is an example of a second edge, and electrode 22c2 is an example of a second electrode.

[0063] As described above, the substrate 22 on which the semiconductor element 31 and the optical semiconductor element 32 are flip-chip mounted is provided with an opening 22f that penetrates in the Z direction (thickness direction of the substrate 22) at a position that partially overlaps with the optical semiconductor element 32.

[0064] When heat is generated during reflow in flip-chip mounting or during operation of the optical module 100, in a configuration without an opening 22f, the difference in thermal expansion coefficients between the substrate 22 and the optical semiconductor element 32 can cause increased stress in at least one of the substrate 22 and the optical semiconductor element 32, potentially leading to a decrease in reliability. In this embodiment, however, since an opening 22f is provided in the substrate 22, even when heat is generated during reflow in flip-chip mounting or during operation of the optical module 100, the stress generated based on the difference in thermal expansion coefficients between the substrate 22 and the optical semiconductor element 32 can be reduced, thereby improving reliability.

[0065] Furthermore, as described above, the provision of an opening 22f in the substrate 22 offers advantages such as facilitating alignment work and improving alignment accuracy by visually inspecting the alignment marker 32b, and miniaturizing the optical module 100 by partially housing components such as the optical component 33. Visual inspection of the alignment marker 32b includes position detection by image processing of images captured by a camera or the like, as well as visual inspection.

[0066] Furthermore, in this embodiment, heat generated in the semiconductor element 31 and the optical semiconductor element 32 can be transferred to and dissipated from the substrate 22 by heat transfer members such as a thermal conductive sheet 41, a heat transfer block 42, a bottom wall 10a, and a heat sink 50, as well as a cooling mechanism such as the TEC 43, which are provided on the side opposite to the substrate 22 relative to the semiconductor element 31 and the optical semiconductor element 32. In a configuration in which the semiconductor element 31 and the optical semiconductor element 32 are flip-chip mounted on the substrate 22, it is difficult to secure a heat dissipation path via the substrate 22, which reduces the heat dissipation efficiency of the heat generated in the semiconductor element 31 and the optical semiconductor element 32, making it difficult to obtain the desired characteristics of the optical module 100 or reducing the reliability of the optical module 100. In this embodiment, the heat generated by the semiconductor element 31 and the optical semiconductor element 32 can be transferred to the side opposite the substrate 22 and dissipated. Therefore, even in a configuration where the semiconductor element 31 and the optical semiconductor element 32 are flip-chip mounted on the substrate 22, it becomes easier to ensure the required heat dissipation, which in turn makes it easier to obtain the desired characteristics of the optical module 100 and easier to ensure the required reliability of the optical module 100.

[0067] [Second Embodiment] Figure 3 is a plan view of the substrate 22B(22) of the second embodiment. As shown in Figure 3, in this embodiment as well, the substrate 22B is provided with an opening 22f. Therefore, in this embodiment as well, the same effects as in the first embodiment can be obtained through the opening 22f and the configuration related to the opening 22f.

[0068] However, in this embodiment, a protrusion 22f1a is provided on the edge 22f1 of the opening 22f. The protrusion 22f1a protrudes in the X direction from approximately the center of the edge 22f1, which extends linearly in the Y direction away from the end edge 22e, and overlaps with the surface 32a of the optical semiconductor element 32 in the Z direction. In other words, the protrusion 22f1a covers the surface 32a with a gap in the Z direction. In addition, multiple electrodes 22c2 (22c) are provided on the protrusion 22f1a. These electrodes 22c2 also constitute part of the conductive path that electrically connects the conductor of the optical semiconductor element 32 and the conductor of the semiconductor element 31. With this configuration, for example, the degree of freedom in the layout of the electrodes and conductors of the optical semiconductor element 32 can be increased. Note that the position, shape, size, number, etc. of the protrusion 22f1a are not limited to the example in Figure 3. For example, the protrusion 22f1a may be provided on the edge 22f2 and protrude in the Y direction or the opposite direction of the Y direction, or it may be provided at any position on the edges 22f1, 22f2, and it may have an electrode 22c1 that transmits a higher frequency signal. In addition, multiple protrusions 22f1a may be provided on the edges 22f1, 22f2.

[0069] [Third Embodiment] Figure 4 is a plan view of the substrate 22C(22) of the third embodiment. As shown in Figure 4, in this embodiment as well, the substrate 22C is provided with an opening 22f. Therefore, in this embodiment as well, the same effects as in the first embodiment can be obtained through the opening 22f and the configuration related to the opening 22f.

[0070] However, in this embodiment, a recess 22f1b is provided on the edge 22f1 of the opening 22f. The recess 22f1b is recessed in the opposite direction in the X direction from both ends of the edge 22f1, which extends linearly in the Y direction at a position away from the end edge 22e. With this configuration, for example, it is possible to suppress the rigidity of the substrate 22C from becoming excessively high near the edges 22f1 and 22f2 of the substrate 22C, especially in the peripheral portion where multiple electrodes 22c are lined up. This may suppress the increase in stress in at least one of the substrate 22 and the optical semiconductor element 32 due to the difference in thermal expansion coefficients between the substrate 22 and the optical semiconductor element 32. Note that the position, shape, size, number, and other specifications of the recess 22f1b are not limited to the example in Figure 4. For example, the recess 22f1b may be provided on the edge 22f2 and recessed in the Y direction or the opposite direction in the Y direction, or it may be provided at any position on the edges 22f1 and 22f2. Furthermore, multiple recesses 22f1b may be provided on the edges 22f1 and 22f2.

[0071] Although embodiments of the present invention have been illustrated above, these embodiments are merely examples and are not intended to limit the scope of the invention. The above embodiments can be implemented in various other forms, and various omissions, substitutions, combinations, and modifications can be made without departing from the spirit of the invention. Furthermore, each configuration, shape, and other specifications (structure, type, orientation, model, size, length, width, thickness, height, number, arrangement, position, material, etc.) can be modified as appropriate.

[0072] For example, the opening may not be a notch, but a through-hole with a circumferential edge that penetrates the substrate in the thickness direction. Furthermore, the location, shape, size, number, and other specifications of the opening are not limited to those exemplified in the embodiment. Note that the opening is not a hole or notch provided in the substrate specifically for passing light through. [Explanation of Symbols]

[0073] 10…Cabinet 10a…Bottom wall 10b…peripheral wall 10c…Ceiling wall 10d... Window components 21…Feedthrough 21a...Conductor 22, 22A~22C… Circuit board 22a…side 22b...face 22c...electrode 22c1...electrode (first electrode) 22c2...electrode (second electrode) 22d...Wiring (conductor wiring) 22e...edge 22f…Aperture 22f1... Connection (First Connection) 22f1a…convex part 22f1b…recess 22f2... Connection (Second Connection) 31... Semiconductor devices 32…Optical semiconductor device 32a...side 32b, 32b1, 32b2… Alignment markers 33…Optical components (parts) 34…Light-emitting unit 41…Heat conductive sheet (heat transfer material) 42… Heat transfer block (heat transfer component) 43…TEC (Cooling mechanism, heat transfer component) 50… Heat sink (heat transfer component) 100… Optical module S... Confinement room X…direction Y... Direction Z... direction (thickness direction)

Claims

1. circuit board and The optical semiconductor element is mounted as a flip chip on the aforementioned substrate, The optical component through which the light output or received by the aforementioned optical semiconductor element passes, Equipped with, The substrate is provided with an opening that penetrates through the substrate in the thickness direction at a position that overlaps with the optical semiconductor element. The aforementioned opening is a notch provided in the edge of the substrate, The optical component is partially housed within the opening, separated from the edge of the opening. The optical semiconductor element outputs or receives light in a direction along the surface of the substrate on which the optical semiconductor element is mounted. An optical module to which light in a direction along the surface is coupled to the optical component.

2. The optical module according to claim 1, wherein the optical semiconductor element is provided with an alignment marker for use in aligning with a component other than the optical semiconductor element, which is visible from the opposite side of the substrate from the optical semiconductor element through the aperture.

3. The optical module according to claim 1 or 2, comprising a component partially housed in the opening.

4. The optical module according to any one of claims 1 to 3, wherein the substrate has a plurality of electrodes electrically connected to the conductor of the optical semiconductor element along the edge of the aperture.

5. The aforementioned opening is a notch provided in the edge of the substrate, The substrate has, as the edge of the notch, a first edge separated from the edge and a second edge extending between the first edge and the edge, The optical module according to claim 4, wherein the plurality of electrodes include a plurality of first electrodes provided along the first edge.

6. The optical module according to claim 5, wherein the substrate has a plurality of second electrodes provided along the second edge as the plurality of electrodes.

7. The optical module according to claim 6, wherein a signal with a higher frequency than that of the second electrode is transmitted at the first electrode.

8. The optical module according to any one of claims 5 to 7, comprising a semiconductor element mounted on the substrate, located on the opposite side of the edge from the optical semiconductor element, and having a conductor electrically connected to the electrode and the substrate via conductive wiring provided on the substrate.

9. The optical module according to any one of claims 1 to 8, wherein a recess or protrusion is provided on the edge of the opening.

10. The optical module according to any one of claims 1 to 9, comprising a cooling mechanism provided on the side opposite to the substrate with respect to the optical semiconductor element for cooling the optical semiconductor element.

11. The optical module according to any one of claims 1 to 10, further comprising a heat transfer member provided on the side opposite to the substrate with respect to the optical semiconductor element, which transfers heat from the optical semiconductor element to the side opposite to the optical semiconductor element.

12. An optical module according to any one of claims 1 to 11, comprising a housing that houses the substrate and the optical semiconductor element.

13. The optical module according to claim 12, wherein a part of the housing is provided on the side opposite to the substrate with respect to the optical semiconductor element and functions as a heat transfer member that transfers heat from the optical semiconductor element to the side opposite to the optical semiconductor element.

14. The optical module according to any one of claims 1 to 13, wherein no underfill is provided between the substrate and the optical semiconductor element.

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