JP7113325B2 - Optical module structure - Google Patents

Description

The present invention relates to an optical module structure for converting an electrical signal into an optical signal and transmitting or receiving the optical signal.

Conventionally, as shown in FIG. 6, the optical module 50 is provided in grooves formed on the surface of the first substrate 51 of each of the light emitting (transmitting) side optical module 50A and the light receiving (receiving) side optical module 50B. An internal waveguide 52 and a mirror portion 53 for optical path conversion formed at the tip of the groove are provided.

A light-emitting element (optical element) 54A for emitting an optical signal is mounted on the surface of the first substrate 51 of the light-emitting side optical module 50A via a mirror portion 53 in the core portion of the internal waveguide 52 . Similarly, on the surface of the first substrate 51 of the light receiving side optical module 50B, a light receiving element (optical element) 54B for receiving an optical signal from the core portion of the internal waveguide 52 via the mirror portion 53 is mounted. ing.

Furthermore, an external waveguide (optical fiber) 55 is optically coupled to the core portion of the internal waveguide 52 in each of the light emitting element 54A and the light receiving element 54B.

On the surface of each first substrate 51, the light emitting element 54A or the light receiving element 54B is flip-chip mounted with bumps interposed therebetween, using the light emitting surface of the light emitting element 54A or the light receiving surface of the light receiving element 54B as the mounting surface. Also, each first substrate 51 is placed on the surface of a different second substrate (interposer substrate) 56 . On the surface of each second substrate 56, there is formed a signal processing section (IC substrate) 57A formed with an IC circuit for transmitting an electrical signal to the light emitting element 54A, or for receiving an electrical signal from the light receiving element 54B. A signal processing section (IC substrate) 57B on which an IC circuit is formed is mounted. The light emitting element 54A and the signal processing section 57A are electrically connected by a looped bonding wire 58, and the light receiving element 54B and the signal processing section 57B are electrically connected by a looped bonding wire 58. Connectors 59 for electrically connecting the signal processing units 57A and 57B to other circuit devices are provided in the respective modules 50A and 50B. They are electrically connected by a loop-shaped bonding wire 60 .

In such an optical module 50, as a method for realizing high-speed transmission of 10 Gbs or more, it is considered to increase the speed per wiring line for transmitting electrical signals or to increase the number of channels to simultaneously transmit a plurality of electrical signals. be done.

In the case of increasing the speed per wiring line, the impedance mismatch due to the inductance component of the bonding wire 58 makes it impossible to ignore the deterioration of the high-frequency signal due to the delay due to signal reflection. Here, since the inductance component is proportional to the length of the bonding wire 58, it is necessary to shorten the length of the bonding wire 58 in order to increase the speed per wiring line.

Further, in the case of multi-channel communication, since a plurality of wirings are arranged in parallel, there is a problem of an increase in crosstalk caused by mutual interference of electric signals between wirings. Generally, crosstalk is caused by capacitive coupling between wires, and measures to reduce it include shortening the wire length, increasing the space between wires, shielding with a GND circuit (ground circuit), and the like.

However, the bonding wire 58 cannot be shielded by the GND circuit, and there is a disadvantage that an increase in the wiring interval increases the size of the optical module. Therefore, the length of the bonding wire 58 must be shortened also when considering multi-channeling.

As another conventional optical module, FIG. 7 shows a cross-sectional view of a light-emitting side optical module structure 40A-1 by bonding wire connection (see, for example, Patent Document 1).

In the optical module structure 40A-1, the surface of the first substrate 1 includes an inclined surface 1e inclined obliquely downward from the vicinity of the bump 12c of the light emitting element 12a, and a horizontal surface 1f extending horizontally from the lower end of the inclined surface 1e. A concave stepped portion 1g is formed.

A metal circuit (a circuit patterned by sputtering copper or gold) 12d connected to the bumps 12c of the light emitting element 12a is formed along the inclined surface 1e and the horizontal surface 1f. A portion is a land 12e. By adopting such a configuration, the height position of the land 12e on the horizontal surface 1f can be formed at a low position so as to approach the height position of the land 4c on the side of the light emitting element 12a of the signal processing section 4a.

The land 12e on the side of the light emitting element 12a and the land 4c on the side of the light emitting element 12a of the signal processing section 4a are electrically connected by a bonding wire 26 having a loop shape.

Furthermore, the lands 4 d of the signal processing section 4 a on the connector 7 side and the lands 7 a of the connector 7 on the surface of the second substrate 6 are electrically connected by loop-shaped bonding wires 27 .

The lands 7 a of the connector 7 are electrically connected to the connector 7 arranged on the back side of the second substrate 6 via the through-hole wirings 6 a of the second substrate 6 .

In FIG. 7, by lowering the height position of the land 12e on the side of the light emitting element 12a using the stepped portion 1g formed on the first substrate 1, the height of the land 4c on the side of the light emitting element 12a of the signal processing section 4a is increased. The difference H can be made smaller. As a result, since the length of the bonding wire 26 can be shortened, deterioration of the high frequency signal can be suppressed and high speed transmission becomes possible.

Japanese Patent No. 5654317

However, in recent years, the development of systems for high-speed transmission of ultra-large-capacity data such as 8K video or data centers using this optical module is progressing. Such a system requires high-speed transmission of 50 Gbs or more, and a 4-value pulse amplitude modulation (PAM4) system is used as a transmission system for such ultra-large-capacity data.

FIG. 8 is a plan view of a light emitting side optical module structure based on a conventional four-level pulse amplitude modulation (PAM4) system. PAM is an abbreviation for Pulse Amplitude Modulation. Conventional binary pulse amplitude modulation (PAM2) modulates and transmits a bit string of 0s and 1s as pulse signals of two voltage levels. In contrast, PAM4 modulates a bit string consisting of 0s and 1s as pulse signals of four voltage levels, 00, 01, 10, and 11, and is capable of transmitting twice as much data as before. .

An optical module applied to such a PAM4 system requires a new communication LSI 801 incorporating a driver circuit and a receiver circuit in order to modulate 2-level to 4-level modulation. Accordingly, the size of the optical module is increased.

Furthermore, with the increase in speed and frequency, transmission loss increases due to wiring such as bonding wires 804 connecting the Si bench substrate 802 and the IC substrate 803, or bonding wires 805 connecting the communication LSI 801 and the IC substrate 803. There is a problem.

Therefore, the present invention solves the problems of the prior art, and by shortening the path connecting the chips that make up the optical module, it is possible to suppress the degradation of high-frequency signals, improve the transmission speed, and reduce the size of the module. It is an object to provide a possible optical module structure.

To achieve the above object, an optical module structure according to one aspect of the present invention comprises a main substrate, an interposer substrate electrically connected to the main substrate via first projecting electrodes, and second projections. A first communication LSI electrically connected to the interposer substrate via electrodes, and an IC element electrically connected to the interposer substrate via side connection terminals and third projecting electrodes of the interposer substrate. a Si bench substrate electrically connected to the IC element via fourth protruding electrodes and side connection terminals; and an optical element electrically connected to the Si bench substrate via fifth protruding electrodes. and an optical fiber optically connected via an optical waveguide formed on the Si bench substrate.

According to the optical module structure of the present invention, it is possible to shorten the path connecting the chips constituting the optical module. A possible optical module structure can be provided.

FIG. 1 is a sectional view showing the structure of a light receiving side optical module structure according to Embodiment 1 of the present invention; FIG. 2 is a plan view showing the configuration of the light receiving side optical module structure according to Embodiment 1 of the present invention; (a) to (g) are cross-sectional views showing steps of forming a light-receiving side optical module structure according to Embodiment 1 of the present invention. FIG. 3 is a cross-sectional view showing the configuration of a light receiving side optical module structure according to Embodiment 2 of the present invention; (a) to (f) are cross-sectional views showing a process of forming rewiring in a light receiving side optical module structure according to Embodiment 2 of the present invention; Cross-sectional view showing the configuration of a conventional optical module structure Cross-sectional view showing the configuration of a light-emitting side optical module structure by conventional bonding wire connection A plan view showing the configuration of a light-emitting side optical module structure based on a conventional four-level pulse amplitude modulation method.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described with reference to the drawings. It should be noted that the same elements are given the same reference numerals, and their description may be omitted.

(Embodiment 1)
FIG. 1 is a cross-sectional view of a light-receiving side optical module, which is an optical module structure according to Embodiment 1 of the present invention, and FIG. 2 is a plan view of the light-receiving side optical module according to Embodiment 1 of the present invention.

<Structure>
The light-receiving side optical module according to Embodiment 1 of the present invention has a laminated structure of an interposer substrate 101, two communication LSIs 105a and 105b, and a Si bench substrate 112. FIG. This laminated structure is arranged on the main substrate 108, the light receiving element 118 is arranged on the upper surface of the laminated structure in the drawing, and the IC element 122 is arranged on the side surface of the laminated structure in the drawing.

As shown in FIG. 1, a communication LSI 105a is arranged on one main surface (upper surface in FIG. 1) of the interposer substrate 101, and a communication LSI 105b is arranged on the other main surface (lower surface in FIG. 1).

Connection terminals 102 are formed on both main surfaces of the interposer substrate 101, and connection terminals 106 are formed on the respective main surfaces (surfaces on the interposer substrate 101 side) of the communication LSIs 105a and 105b. The connection terminals 102 on the upper surface of the interposer substrate 101 and the connection terminals 106 of the communication LSI 105a are electrically connected via the second projecting electrodes 107 . Also, the connection terminals 102 on the lower surface of the interposer substrate 101 and the connection terminals 106 of the communication LSI 105b are electrically connected via the second protruding electrodes 107 .

A cavity 109, which is a concave portion, is formed on one main surface (upper surface in FIG. 1) of the main substrate 108, and the communication LSI 105b is arranged in this cavity 109. As shown in FIG. That is, on the bottom surface of the cavity 109 of the main board 108, the other main surface (lower surface in FIG. 1) of the communication LSI 105b is arranged.

Connection terminals 110 are formed outside the cavity 109 on the upper surface of the main substrate 108 . Some of the connection terminals 102 on the lower surface of the interposer substrate 101 are electrically connected to the connection terminals 110 of the main substrate 108 via the first projecting electrodes 111 .

A light receiving element 118 is arranged on one main surface (upper surface in FIG. 1) of the Si bench substrate 112 . Connection terminals 113 are formed on the upper surface of the Si bench substrate 112 , and connection terminals 119 are formed on the lower surface of the light receiving element 118 . The connection terminal 113 of the Si bench substrate 112 and the connection terminal 119 of the light receiving element 118 are electrically connected via the fifth projecting electrode 115 . A connection portion between the Si bench substrate and the light receiving element 118 is sealed with a sealing material 120 .

Between the other main surface (upper surface in FIG. 1) of the communication LSI 105a and the other main surface (lower surface in FIG. 1) of the Si bench substrate 112, a heat radiation sheet 121 for thickness adjustment is arranged. The communication LSI 105a and the Si bench substrate 112 are joined with a heat radiation sheet 121 interposed therebetween.

An IC element 122 is arranged on the side surface (the left side in FIG. 1) of the interposer substrate 101 and the Si bench substrate 112 . In Embodiment 1, a TIA element, for example, is adopted as the IC element 122 . A TIA element, a Transimpedance Amplifier (hereinafter abbreviated as TIA), is an IC element used in a receiving system of an optical communication system. A plurality of connection terminals 123 are formed on the main surface of the IC element 122 (the right surface in FIG. 1).

Side connection terminals 104 are formed on the side surface (left side surface in FIG. 1) of the interposer substrate 101 . Here, the side surface of the interposer substrate 101 is a surface that connects the ends of the opposing principal surfaces (upper surface and lower surface in FIG. 1) of the interposer substrate 101 . The side connection terminal 104 of the interposer substrate 101 and one connection terminal 123 of the IC element 122 face each other and are electrically connected via the third projecting electrode 124a.

A side connection terminal 114 is formed on the side surface (the left side surface in FIG. 1) of the Si bench substrate 112 . Here, the side surface of the Si bench substrate 112 is a surface that connects the ends of the opposing main surfaces (upper surface and lower surface in FIG. 1) of the Si bench substrate 112 . The side connection terminal 114 of the Si bench substrate 112 and another connection terminal 123 of the IC element 122 face each other and are electrically connected via the fourth projecting electrode 124b.

A connection portion between the main substrate 108 and the interposer substrate 101, a connection portion between the interposer substrate 101 and the communication LSIs 105a and 105b, and a connection portion between the IC element 122 and the interposer substrate 101 and the Si bench substrate 112 are sealed with a sealing material 125. It is

An optical waveguide 116 is provided on the Si bench substrate 112 , and a light receiving element 118 and an optical fiber 126 are optically connected via the optical waveguide 116 .

<Dimensions>
Each member constituting the optical module of the first embodiment is not limited in shape and size, but may be formed with the following dimensional configuration, for example.
Main substrate 108: 10 mm x 10 mm x thickness 1.0 mm
Interposer substrate 101: 6 mm x 6 mm x thickness 0.4 mm
Communication LSI 105a, 105b: 5mm x 5mm x thickness 0.4mm
Si bench substrate 112: 3 mm × 3 mm × thickness 0.4 mm
IC element 122: 2mm x 2mm x thickness 0.25mm
Light receiving element 118: 1 mm x 1 mm x thickness 0.15 mm

At this time, the connection terminal pitch 127 of the IC element 122, that is, the interval dimension between the connection terminals 123 of the IC element 122 connected to the interposer substrate 101 and the connection terminals 123 of the IC element 122 connected to the Si bench substrate 112 is 1. 0.5 mm.

The junction height of the second projecting electrode 107 connecting the interposer substrate 101 and the communication LSI 105a is 50 μm.

In such a dimensional configuration, the side connection terminals 104 of the interposer substrate 101 and the Si bench substrate 112 can be separated from each other by setting the thickness of the heat dissipation sheet 121 for thickness adjustment arranged between the communication LSI 105a and the Si bench substrate 112 to 0.65 mm. and the side connection terminal 114 can also be adjusted to 1.5 mm. As a result, the distance between the two connection terminals 123 of the IC element 122 and the distance between the side connection terminals 104 of the interposer substrate and the side connection terminals 114 of the Si bench substrate 112 become equal. Therefore, the IC element 122 can be connected and arranged on the side surfaces of the interposer substrate 101 and the Si bench substrate 112 . The thickness-adjusting heat dissipation sheet 121 has a role as a thickness-adjusting sheet for adjusting the distance between the connection terminals 123 and the distance between the side connection terminals 104 and 114, and its thickness can be adjusted as described above. It is set according to the distance to be taken.

As described above, in the optical module of the first embodiment, the path connecting the elements constituting the optical module can be shortened, the deterioration of the high-frequency signal can be suppressed, the transmission speed can be improved, and the size can be reduced. A possible optical module structure can be provided.

Further details of each component constituting the optical module of the first embodiment will be described below.

<Connection terminal>
The connection terminals 102, 106, 113, 119, 123 are made of a conductive material. As such a conductive material, for example, aluminum may be used, or a metal such as copper having a higher conductivity than aluminum may be used. can be The connection terminal 110 is made of a conductive material. As such a conductive material, for example, copper or the like may be used, and copper or the like may be subjected to nickel/gold plating treatment to make it difficult to oxidize. The side connection terminals 104, 114 are made of a conductive material. As such a conductive material, for example, copper or the like may be used, and the copper or the like may be plated with nickel/gold to make it difficult to oxidize.

<Protruding electrode>
The second projecting electrode 107, the first projecting electrode 111, the fifth projecting electrode 115, the third projecting electrode 124a, and the fourth projecting electrode 124b are made of a conductive material. As such a conductive material, for example, solder or the like may be used, or metal such as copper or gold may be used.

<Interposer board>
The interposer substrate 101 is made of, for example, a ceramic substrate, but a Si substrate, a buildup substrate, an aramid epoxy substrate, or the like may also be used.

<Main board>
The main board 108 is formed of, for example, a glass epoxy board, but a buildup board, an aramid epoxy board, a ceramic board, or the like may also be used. In the case where the optical module is arranged on another component, the other component may have the function of the main substrate.

<Cavity>
The size of the cavity 109 is, for example, 6 mm×6 mm×0.4 mm in thickness. Both are 50 μm, and the interposer substrate 101 and the main substrate 108 can be connected by the shortest path. It is not limited to the case where the entire thickness of the communication LSI 105b fits within the cavity 109, and the case where part of the thickness of the communication LSI 105b fits within the cavity 109 is also possible.

<Heat release sheet for thickness adjustment>
The thickness adjusting heat dissipation sheet 121 plays a role of thickness adjustment for adjusting the distance between the Si bench substrate 112 and the communication LSI 105a as described above, and also dissipates heat transmitted from the Si bench substrate 112 and the communication LSI 105a. have a role to play. The thickness-adjusting heat dissipation sheet 121 may be formed of, for example, a film, or paste, silicone, or the like may be used. A material softer than other laminates, communication LSIs 105 a and 105 b, interposer substrate 101 , main substrate 108 , and Si bench substrate 112 may be used for thickness adjustment heat radiation sheet 121 . By using such a soft material, the stress generated in each connection portion can be relieved by the thickness adjusting heat dissipation sheet 121, and the reliability of connection can be improved.

The distance between the two connection terminals 123 of the IC element 122 and the distance between the side connection terminals 104 of the interposer substrate and the side connection terminals 114 of the Si bench substrate 112 can be reduced without using the heat dissipation sheet 121 for thickness adjustment. and are equal to each other, the heat radiation sheet 121 for adjusting the thickness may not be used.

<Communication LSI>
Although the structure in which the two communication LSIs 105a and 105b are arranged on both sides of the interposer substrate 101 has been described as an example, the structure is not limited to this. Instead of such a structure, for example, two communication LSIs 105 a and 105 b may be arranged on one main surface of the interposer substrate 101 . Further, the optical module may include only one communication LSI 105, or may include three or more. When only one communication LSI 105 is provided, the communication LSI 105 may be arranged on one main surface (upper surface in FIG. 1) of the interposer substrate 101 . A communication LSI is an example of an IC element for communication.

<Light receiving element>
In the light-receiving-side optical module of Embodiment 1, the case where the light-receiving element 118 is used as a photodiode for optical-to-electrical conversion of an optical signal passing through the optical fiber 126 and the optical waveguide 116 is taken as an example. For example, when the optical module structure is a light emitting side optical module, a light emitting element is used instead of the light receiving element 118 . A VCSEL element or an LED element may be used as the light emitting element. Here, the VCSEL element is an abbreviation for Vertical Cavity Surface Emitting Laser, and is a type of semiconductor laser that resonates light in the direction perpendicular to the substrate surface and emits light in the direction perpendicular to the surface. . The light receiving element 118 and the light emitting element are examples of optical elements, and the optical module structure may include the optical elements.

<IC element>
In the light-receiving-side optical module of Embodiment 1, the IC element 122 is used as an example of a transimpedance amplifier that performs optical-electrical conversion in the light-receiving element 118, converts the impedance of the electric signal, amplifies it, and outputs it. . When the optical module structure is a light emitting side optical module, the IC element may be a driver element for driving the light emitting element.

<Si bench substrate>
By using the Si bench substrate 112, the crystal orientation of Si can be used to enable highly precise etching groove processing on the surface, and the flatness is also improved.

<Optical waveguide, optical fiber>
An optical waveguide 116 optically coupled with the IC element 122 and an optical fiber 126 optically coupled with the optical waveguide 116 are arranged, but the optical waveguide 116 is not necessarily provided.

<Manufacturing method>
FIG. 3 shows an example of a manufacturing process for manufacturing such a light-receiving side optical module.

First, as shown in FIG. 3A, connection terminals 102 are formed on each main surface of an interposer substrate 101, through-holes 103 for penetrating connection between the two main surfaces are formed, and side connection terminals 104 are formed on the side surfaces. to form

Next, as shown in FIG. 3B, two communication LSIs 105a and 105b are superimposed on both main surfaces of the interposer substrate 101, and the connection terminals 102 of the interposer substrate 101 and the connection terminals 106 of the communication LSIs 105a and 105b are connected to each other. It is electrically connected through the projecting electrode 107 . After that, the communication LSI 105b is placed in the cavity 109 formed in the main substrate 108, and the connection terminals 102 of the interposer substrate 101 and the connection terminals 110 of the main substrate 108 are electrically connected via the first projecting electrodes.

By adjusting the depth of the cavity 109, it becomes possible to adjust the gap between the connection terminal 102 of the interposer substrate 101 and the connection terminal 110 of the main substrate 108, and the shortest path connection is established via the first projecting electrode 111. becomes possible.

On the other hand, as shown in FIG. 3(c), a connection terminal 113 is formed on the main surface of a Si bench substrate 112, side connection terminals 114 are formed on the side surface, and a fifth projecting electrode 115 is formed on the connection terminal 113. . Further, an optical waveguide 116 and a V-groove 117 are formed on the Si bench substrate 112 .

Next, as shown in FIG. 3(d), the light receiving element 118 is placed on the Si bench substrate 112, and the connection terminal 113 of the Si bench substrate 112 and the connection terminal 119 of the light receiving element 118 are connected to each other by the fifth projecting electrode 115. The connecting portion is sealed and fixed with a sealing material 120 .

Next, as shown in FIG. 3(e), the Si bench substrate 112 is placed on the communication LSI 105a via the heat dissipation sheet 121 for adjusting the thickness and bonded.

At this time, the distance between the side connection terminals 104 of the interposer substrate 101 and the side connection terminals 114 of the Si bench substrate 112 can be adjusted to a predetermined distance by adjusting the thickness of the thickness-adjusting heat radiation sheet 121 . It becomes possible.

Next, as shown in FIG. 3F, IC elements 122 are arranged on the side surfaces of the interposer substrate 101 and the Si bench substrate 112 . The side connection terminals 104 of the interposer substrate 101 and the connection terminals 123 of the IC element 122 are electrically connected via the third projecting electrodes 124a, and the side connection terminals 114 of the Si bench substrate 112 and the connection terminals 123 of the IC element 122 are electrically connected. are electrically connected via the fourth projecting electrode 124b.

Finally, as shown in FIG. 3G, each connecting portion is sealed and fixed with a sealing material 125 . An optical fiber 126 is placed in the V-groove 117 of the Si bench substrate 112 to complete the receiving side optical module.

<effect>
According to the optical module of the first embodiment, the paths connecting the light receiving element 118, the Si bench substrate 112, the IC element 122, the interposer substrate 101, the communication LSIs 105a and 105b, and the main substrate 108, which constitute the optical module, are shortened. be able to. As a result, deterioration of the high frequency signal can be suppressed and the transmission speed can be increased. Further, by adjusting the thickness of the thickness-adjusting heat dissipation sheet 121, it is possible to relax the stress at the joint portion and provide a highly reliable and compact optical module structure.

(Embodiment 2)
FIG. 4 shows a sectional view of a light-receiving side optical module as an optical module structure according to Embodiment 2 of the present invention. In the optical module according to the second embodiment of the present invention, differences from the optical module according to the first embodiment will be mainly described below, and descriptions of substantially similar parts will be omitted.

Side connection terminals 404 formed on the interposer substrate 401 are electrically connected to connection terminals 429 formed on the IC element 422 via third projecting electrodes 424 .

The interposer substrate 401 is formed thin so that the thickness of the interposer substrate 401 is equal to or less than the outer diameter of the third projecting electrode 424 (for example, the vertical length dimension in FIG. 4).

As a result, the aspect ratio (ratio of width/height in FIG. 4) of the through hole 403 penetrating between the main surfaces of the interposer substrate 401 is increased, and the resistance value of the through hole 403 can be decreased. Therefore, it is possible to suppress deterioration of high-frequency signals in the optical module.

Furthermore, at least part of the wiring connecting the connection terminals 413 formed on the main surface (upper surface in FIG. 4) of the Si bench substrate 412 and the side connection terminals 414 formed on the side surface (left side surface in FIG. 4) A sloping portion 428 is formed that is slanted with respect to the surface and side surfaces. By providing such an inclined portion 428, the wiring length on the Si bench substrate 412 is shortened compared to the case where the inclined portion 428 is not provided, and transmission loss can be suppressed.

Here, the inclination means that the surface (main surface) on which the connection terminal 413 is formed is inclined with respect to the surface (side surface) on which the side connection terminal 414 is formed.

In the optical module of the second embodiment, each terminal provided on the IC element 422 itself is rewired so that the interval between the side connection terminals 404 of the interposer substrate 401 and the side connection terminals 414 of the Si bench substrate 412 is the same. Connection terminals (rewiring connection terminals) 429 of the IC element 422 are formed so as to be .

<Rewiring>
5(a) to 5(f) show the steps of forming the rewiring of the IC element 422. FIG.

5(a) to 5(c) are cross-sectional views of the IC element 422, and FIGS. 5(d) to 5(f) are plan views of the IC element 422. FIG.

First, as shown in FIGS. 5A and 5D, an IC element 422 has a plurality of terminals 423 arranged thereon.

Next, as shown in FIGS. 5(b) and 5(e), a rewiring layer 430 is formed, and the interval between the connection terminals of the IC element 422 is adjusted to a predetermined interval. A plurality of connection terminals (rewiring connection terminals) 429 are arranged outside.

Finally, as shown in FIGS. 5(c) and 5(f), the rewiring is completed by forming the third projecting electrodes 424 on the connection terminals 429. FIG.

Note that rewiring means that the connection terminals 429 are arranged outside the IC element 422 in parallel with the outer surface.

<effect>
According to the optical module of the second embodiment, it is possible to shorten the path connecting the elements constituting the optical module, suppress deterioration of the high-frequency signal, and increase the transmission speed. Moreover, even if the IC element is a general-purpose component, it can be connected to the side connection terminals by adjusting the interval between the connection terminals by rewiring, and a compact optical module structure can be provided.

By appropriately combining any of the various embodiments described above, the respective effects can be obtained.

Although the invention has been fully described in connection with preferred embodiments and with reference to the accompanying drawings, various variations and modifications will become apparent to those skilled in the art. Such variations and modifications are to be included therein insofar as they do not depart from the scope of the invention as set forth in the appended claims.

The optical module structure of the present invention can be applied to many devices using optical communication. It can be used in equipment that communicates large amounts of data, such as digital video equipment and broadcasting equipment.

1 Substrate 1e Inclined surface 1f Horizontal surface 4a Signal processing unit 4c Land 4d Land 6 Substrate 6a Through hole wiring 7 Connector 7a Land 12a Light emitting element 12c Bump 12e Land 26 Bonding wire 27 Bonding wire 50 Optical module 50A Light emitting side optical module 50B Light receiving side module 51 substrate 52 internal waveguide 53 mirror portion 54A light emitting element 54B light receiving element 56 substrate 57A signal processing portion 58 bonding wire 59 connector 60 bonding wire 101 interposer substrate 102 connection terminal 103 through hole 104 side connection terminal 105 communication LSI
105a Communication LSI
105b Communication LSI
106 connecting terminal 107 second protruding electrode 108 main substrate 109 cavity 110 connecting terminal 111 first protruding electrode 112 Si bench substrate 113 connecting terminal 114 side connecting terminal 115 fifth protruding electrode 116 optical waveguide 117 V groove 118 light receiving element 119 connecting terminal 120 Sealing material 121 Heat dissipation sheet for adjusting thickness 122 IC element 123 Connection terminal 124a Third projecting electrode 124b Fourth projecting electrode 125 Sealing material 126 Optical fiber 127 Connection terminal pitch 401 Interposer substrate 403 Through hole 404 Side connection terminal 412 Si bench substrate 413 Connection terminal 414 Side connection terminal 422 IC element 423 Terminal 424 Third projecting electrode 428 Inclined portion 429 Connection terminal 430 Rewiring layer 801 Communication LSI
802 Si bench substrate 803 substrate 804 bonding wire 805 bonding wire

Claims (9)

main board and
having a first main surface and a second main surface opposite to the first main surface, the first main surface being arranged to face the main substrate ; an interposer substrate electrically connected to the main substrate;
a first communication LSI arranged to face the second main surface of the interposer substrate and electrically connected to the interposer substrate via second projecting electrodes;
The interposer substrate is electrically connected to the interposer substrate via a first side connection terminal provided on a side surface connecting an end portion of the first principal surface and an end portion of the second principal surface of the interposer substrate and a third projecting electrode. an IC element connected to
It has a third main surface and a fourth main surface located on the opposite side of the third main surface, and is provided on a side surface connecting an end of the third main surface and an end of the fourth main surface. a Si bench substrate electrically connected to the IC element via a second side connection terminal and a fourth projecting electrode;
an optical element electrically connected to the Si bench substrate via a fifth projecting electrode;
an optical fiber optically connected via an optical waveguide formed on the Si bench substrate;
An optical module structure comprising: 2. The optical module structure according to claim 1, comprising a second communication LSI electrically connected to said interposer substrate. 3. The optical module structure according to claim 2, wherein said main substrate has a cavity, and said second communication LSI is located in said cavity. 4. The optical module structure according to any one of claims 1 to 3, further comprising a heat radiation sheet disposed between said first communication LSI and said Si bench substrate to join them together. 5. The optical module structure according to claim 4, wherein said heat radiation sheet is softer than said communication LSI, said interposer substrate, said main substrate, and said Si bench substrate. The IC element has a connection terminal connected to the third projecting electrode and a connection terminal connected to the fourth projecting electrode,
The interposer substrate is arranged such that the distance between the connection terminals of the IC element and the distance between the first side connection terminals of the interposer substrate and the second side connection terminals of the Si bench substrate are equal to each other. 6. The optical module structure according to claim 4, wherein said heat radiation sheet is arranged as a thickness adjusting sheet between said Si bench substrate and said Si bench substrate. The optical module structure according to any one of claims 1 to 6, wherein the thickness of the interposer substrate is equal to or less than the outer diameter of the third projecting electrodes. The Si bench substrate has connection terminals connected to the fifth projecting electrodes provided on the third main surface, and at least part of wiring connecting the connection terminals of the Si bench substrate and the second side surface connection terminals is , inclined with respect to said third main surface and said side surface of said Si bench substrate . The connection terminals are re-wired on the outer surface of the IC element so as to be the same as the distance between the first side connection terminals of the interposer substrate and the second side connection terminals of the Si bench substrate. 7. The optical module structure according to claim 6 .

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