JP5173647B2 - Subcarrier for light receiving element and optical semiconductor device - Google Patents

Description

  The present invention relates to a light receiving element subcarrier for mounting a light receiving element and an optical semiconductor device including the same.

  A conventional subcarrier for a light receiving element has an element mounting surface for mounting the light receiving element and an electrical pattern electrically connected to the electrode of the light receiving element. An electric circuit including the light receiving element is formed by mounting the light receiving element on the mounting surface and electrically connecting the electrical pattern and the light receiving element via a bonding wire (see, for example, Patent Document 1).

An optical fiber serving as a light source is optically coupled to the light receiving element, and an electric signal is output from the light receiving element in accordance with a change in the intensity of the optical signal emitted from the light source.
Japanese Patent Laid-Open No. 10-223923

  However, since the conventional subcarrier for a light receiving element is formed of a dielectric and has low thermal conductivity, heat generated from the light receiving element may be accumulated near the element mounting surface for mounting the light receiving element. There is a problem that the operability of the light receiving element is lowered.

  Therefore, a subcarrier for a light receiving element that can improve the operability of the light receiving element has been desired.

  The subcarrier for a light receiving element of the present invention has an upper surface and a side surface, a mounting surface on which the light receiving element is to be mounted on the side surface, and the mounting surface and the optical fiber are predetermined when viewed from above. A base disposed at an angle; and a conductor provided on the mounting surface and disposed in a U-shape so as to surround the light receiving element, and the U-shaped on the one side of the base It has a conductor opening.

  In the light receiving element subcarrier, the U-shaped opening of the conductor is preferably provided on the upper surface side of the base.

  In the light receiving element subcarrier, the conductor is preferably extended to the upper surface of the base, and is preferably formed to be thicker sequentially from the light receiving element side to the outside.

  In addition, the conductor preferably has an arithmetic average surface roughness Ra defined by JIS B 0601 of 0.2 or more, and further preferably has a gold film on its surface.

  In the light receiving element subcarrier, the base is preferably made of ceramics.

  The optical semiconductor device of the present invention includes the light receiving element subcarrier configured as described above and a light receiving element mounted on the mounting surface.

  The subcarrier for a light receiving element of the present invention has an upper surface and a side surface, a mounting surface on which the light receiving element is to be mounted on the side surface, and the mounting surface and the light source are at a predetermined angle when viewed from above. And a conductor provided on the mounting surface and disposed in a U shape so as to surround the light receiving element, and the U-shaped conductor on one side of the substrate. Even if heat is generated from the light receiving element, the heat generated from the light receiving element by the U-shaped conductor can be diffused over the entire surface of the U-shaped conductor. It is possible to prevent heat from being accumulated in the vicinity. Therefore, it is possible to provide a light receiving element subcarrier capable of improving the operability of the light receiving element.

  Since the light receiving element subcarrier has an opening of the U-shaped conductor on the upper surface side of the base, wiring to which one pole of the light receiving element is connected can be routed from the opening to the upper surface. Furthermore, the U-shaped conductor can be extended to the upper surface. Therefore, it is possible to obtain a subcarrier for a light receiving element in which wiring is formed on the upper surface and connection to the outside is easy with a bonding wire or the like.

  Since the optical semiconductor device of the present invention includes the light receiving element subcarrier having the above-described configuration and the light receiving element mounted on the mounting surface, it is possible to prevent heat from being accumulated in the light receiving element. An optical semiconductor device that can prevent a temperature rise and operates normally and stably can be obtained.

  Hereinafter, the subcarrier for a light receiving element and the optical semiconductor device according to the present embodiment will be described in detail.

  FIG. 1 is a perspective view showing an embodiment of a subcarrier for a light receiving element and an optical semiconductor device according to this embodiment. FIG. 2 is a perspective view showing another example of the embodiment of the subcarrier for light receiving elements and the optical semiconductor device according to the present embodiment. FIGS. 3A and 3B are plan views showing examples of the state in which the optical semiconductor device shown in FIG. 1 is mounted inside the optical semiconductor element storage package.

  In the figure, 1 is a base, 1a is an upper surface of the base 1, 1b is a side surface of the base 1, 1c is a mounting surface on which the light receiving element 4 provided on the side 1b is mounted, and 2 is arranged so as to surround the light receiving element 4. The conductors (U-shaped conductors) 4 are light receiving elements mounted on the mounting surface 1c.

  The subcarrier for a light receiving element according to this embodiment includes a base 1 having an upper surface 1a and a side surface 1b. The side surface 1b of the base 1 has a mounting surface 1c on which the light receiving element 4 is to be mounted, and a conductor 2 arranged in a U-shape so as to surround the light receiving element 4 is formed around the mounting surface 1c. . Further, the base body 1 is arranged such that an angle formed by the mounting surface 1c and the direction in which the optical fiber serving as the light source 7 extends is a predetermined angle θ. The light source 7 is made of, for example, an optical fiber, and the light source 7 and the light receiving element 4 are disposed so as to be optically coupled.

  With this configuration, when heat is generated from the light receiving element 4, the heat generated from the light receiving element 4 by the U-shaped conductor 2 can be diffused over the entire surface of the U-shaped conductor 2, and around the mounting surface 1c. It can dissipate the heat that remains. Therefore, the subcarrier for the light receiving element that can improve the operability of the light receiving element 4 can be obtained.

  Further, with this configuration, depending on the positional relationship between the light source 7 and the light receiving element 4, even if a part of the light emitted from the tip of the light source 7 is diffused and emitted outside the light receiving element 4, the U-shaped conductor 2 The diffused optical signal is reflected and can be effectively guided to the light receiving element 4.

  Since the optical device according to the present embodiment includes the light receiving element subcarrier having the above-described configuration and the light receiving element 4 mounted on the mounting surface 1c, the light receiving element 4 can be prevented from trapping heat to receive light. The temperature rise of the element 4 can be prevented, and an optical semiconductor device that operates normally and stably can be obtained.

  Hereinafter, each component of the light receiving element subcarrier and the optical semiconductor device according to the present embodiment will be described in detail.

A dielectric is used in a portion of the substrate 1 where at least a metal layer such as a conductor 2 and a second conductor 3 is formed in a wiring pattern. Examples of the dielectric constituting the substrate 1 include ceramics such as alumina (Al ₂ O ₃ ) ceramics, aluminum nitride (AlN) ceramics, mullite (3Al ₂ O ₃ · 2SiO ₂ ) ceramics, resins, glasses, and the like. Is used.

  The site | part except the location in which the metal layers, such as the conductor 2 of the base | substrate 1, the 2nd conductor 3, etc. are adhere | attached, may consist of metals. That is, a metal layer such as the conductor 2 and the second conductor 3 may be attached to a metal base via a dielectric. 1, 2, and 3, the metal layers such as the conductor 2 and the second conductor 3 are cross-hatched.

  Examples of the metal constituting the substrate 1 include iron (Fe) -nickel (Ni) -cobalt (Co) alloy, Fe-Ni alloy, copper (Cu) -tungsten (W), Cu-molybdenum (Mo), Cu , Aluminum (Al), stainless steel (SUS), and the like. When made of metal, there is an advantage that heat can be efficiently dissipated even when heat is generated from the light receiving element 4 mounted on the mounting surface 1c.

  The base 1 has a mounting surface 1c on which a light receiving element 4 such as a photodiode (PD) is to be mounted on a side surface 1b. In the example shown in FIGS. 1 and 2, the mounting surface 1 c also has a function as an electrode on which one of the positive electrode and the negative electrode of the light receiving element 4 is flip-chip mounted, and is made of a metal layer. Hereinafter, this metal layer will be described as the second conductor 3.

  The light receiving element 4 has solder (eg, gold (Au) -tin (Sn) solder, Au-germanium (Ge) solder, silver (Ag) -Sn solder), epoxy resin, acrylic resin, or silicone resin on the mounting surface 1c. It is mounted on the substrate 1 by being bonded and fixed using a resin adhesive such as.

  When using solder such as Au—Sn solder, Au—Ge solder, Ag—Sn solder, etc., it has excellent heat resistance, so that the adhesive strength is maintained even when the optical semiconductor device is used in a high temperature atmosphere of 100 ° C. or higher. There is an effect that can be.

  In addition, when an epoxy resin-based resin adhesive is used, there is an advantageous effect in terms of adhesive strength as compared with other resins.

  Further, when the resin adhesive is an acrylic resin type or a silicone resin type, there is an effect that the light receiving element 4 can be bonded and fixed over a long period in that the deterioration due to light is small.

  In the example shown in FIGS. 1 and 2, the other pole of the light receiving element 4 is electrically connected to the conductor 2 via a bonding wire 5.

For example, when the substrate 1 is made of ceramic, the metal layers such as the conductor 2 and the second conductor 3 are formed by depositing a metal layer made of W, Mo, Mn, Cu or the like by a conventionally known metallization method. The metal layers such as the conductor 2 and the second conductor 3 may be formed by a thin film forming method. In this case, the metal layers such as the conductor 2 and the second conductor 3 are formed of tantalum nitride (Ta ₂ N), nichrome (Ni -Cr alloy), titanium (Ti), palladium (Pd), platinum (Pt) and the like.

  Further, when the substrate 1 is made of resin, the metal layers such as the conductor 2 and the second conductor 3 are made of a metal layer such as Cu, and are deposited by a conventionally known plating method or the like.

  Further, a protective metal layer having excellent corrosion resistance, such as gold (Au) or nickel (Ni), is further applied to the metal layers such as the conductor 2 and the second conductor 3 exposed on the surface of the substrate 1 by a plating method or the like. With this configuration, the metal layers such as the conductor 2 and the second conductor 3 can be made difficult to corrode.

  Next, the conductor 2 will be described. The conductor 2 is formed in a shape having an opening 2a opened on one side on the upper surface 1a side which is closed on the surface of the rectangular parallelepiped base body 1 in a U-shape. Hereinafter, it is also referred to as a U-shaped conductor 2. As shown in FIGS. 1 and 2, the U-shaped conductor 2 is provided around the mounting surface 1 c of the base 1 and is disposed in an insulated state from the light receiving element 4 so as to surround the light receiving element 4. . The opening 2a of the U-shaped conductor 2 is located, for example, on the upper surface 1a side as shown in FIG. Or as shown in FIG. 2, the opening 2a of the U-shaped conductor 2 is located in the side surface side. In FIG. 2, it is located on one side of the right side surface.

  Since the opening 2a of the U-shaped conductor 2 is located on the upper surface 1a side as shown in FIG. 1, the tip end portion of the conductor 2 is extended to the upper surface 1a of the base 1, and two left and right portions of the upper surface 1a are provided. A conductor 2 can be provided on the substrate. By providing the conductor 2 on the upper surface 1a, the conductor 2 and the external circuit can be electrically connected by the bonding wire 6 on the upper surface 1a, and workability of the electrical connection can be improved.

  Further, in the case shown in FIG. 1, the second conductor 3 is also preferably extended to the upper surface 1a of the base 1 and routed to both left and right ends of the upper surface 1a. That is, the second conductor 3 is preferably formed in a T shape on the upper surface 1 a in a top view, and the conductor 2 and the second conductor 3 can be provided on both the left and right sides of the upper surface 1 a of the base 1. And it becomes possible to connect to the outside of either the left or right side of the base 1.

  Therefore, the conductor 2 and the second conductor 3 are preferably extended to the upper surface 1 a of the base 1. With this configuration, when the optical device is mounted in the optical semiconductor element storage package 10, as shown in FIG. 3A, the conductor 2 formed on the right side of the upper surface 1a of the base 1 and the optical semiconductor element storage When the package 10 is viewed from above, the wiring conductor 12a of the right input / output terminal 12 can be electrically connected by an external connection conductor 6 such as a bonding wire. Further, as shown in FIG. 3B, the conductor 2 formed on the left side of the upper surface 1a of the base 1 and the wiring provided on the input / output terminal 12 of the optical semiconductor element housing package 10 on the left side when viewed from above. The conductor 12a can be electrically connected by an external connection conductor 6 such as a bonding wire. That is, the optical semiconductor device can be electrically connected to either the left or right.

  Conventionally, it has been necessary to prepare different light receiving element subcarriers for each input / output terminal 12 provided on each of the left and right sides of each optical semiconductor element storage package 10 to manufacture an optical device. On the other hand, the present invention can provide an optical device that can be electrically connected regardless of whether the input / output terminals 12 are provided on the left and right. Accordingly, if only one type of light receiving element subcarrier common to the left and right is prepared, a left and right shared optical device can be manufactured. As a result, the design of the subcarrier for the light receiving element can be shared between the left and right, and the cost can be reduced.

  As shown in FIG. 2, the subcarrier for a light receiving element according to the present embodiment may be provided with an opening 2a of a U-shaped conductor 2 on the side surface side on the side surface 1b.

  In this case, the second conductor 3 is routed from the side surface 1b to the side surface on the opening 2a side. Also in this configuration, the conductor 2 and the second conductor 3 are preferably extended on the upper surface 1a of the base 1, and are electrically connected to the input / output terminals 12 and the like in the optical semiconductor element housing package 10 by the bonding wires 6. Easy to do. By performing electrical connection to the conductor 2 with the bonding wire 6 on the upper surface 1a, workability of electrical connection can be improved. The second conductor 3 may be routed to the upper surface 1a through the adjacent side surface of the U-shaped conductor 2 on the opening 2a side.

  Preferably, the shape of the conductor 2 is formed so as to gradually increase from the light receiving element 4 side to the outside. With this configuration, heat can be easily spread to the outside of the conductor 2 where the conductor 2 is thick, that is, the outside of the base 1, and the heat can be effectively suppressed from being accumulated around the mounting surface of the light receiving element 4. Can do.

  In addition, the surface of the conductor 2 is inclined toward the light receiving element 4, and leakage light from the light source 7 can be more effectively guided to the light receiving element 4 by reflection on the surface of the conductor 2. As a result, the light receiving efficiency of the light receiving element 4 can be increased.

  In order to form the conductor 2 so as to be gradually thicker toward the outside, for example, a metal member that is gradually thickened toward the outside may be bonded to the surface of the base 1 to form the conductor 2.

  Preferably, the conductor 2 has an arithmetic average surface roughness Ra defined by JIS B 0601 of 0.2 or more. With this configuration, the surface of the conductor 2 is roughened to improve heat dissipation on the surface of the conductor 2, and the heat generated from the light receiving element 4 can be efficiently dissipated from the surface of the conductor 2 to the outside of the substrate 1. it can. As a result, the operability of the light receiving element 4 can be further improved. The surface roughness Ra of the conductor 2 can be measured using, for example, a New View 5032 apparatus manufactured by ZYGO.

  Preferably, the conductor 2 is provided with a gold (Au) coating on the surface thereof. With this configuration, corrosion due to oxidation or the like hardly occurs on the surface of the conductor 2, and the thermal conductivity is excellent, so that the thermal conductivity can be well maintained over a long period of time. As a result, it is possible to prevent heat from being trapped around the element mounting surface for a long period of time, and to provide a light receiving element subcarrier capable of operating the light receiving element satisfactorily for a long period of time.

  Preferably, the substrate 1 is made of ceramics. With this configuration, the insulation between the mounting surface 1c and the conductor 2 becomes excellent, the distance between the mounting surface 1c and the conductor 2 can be reduced, and the subcarrier for the light receiving element can be reduced in size. .

  With the above configuration, a subcarrier for a light receiving element can be formed.

  By mounting the light receiving element 4 on the mounting surface 1c of the subcarrier for the light receiving element, an optical semiconductor device is obtained.

  For example, the optical semiconductor device is housed in a container 11 as shown in FIGS. 3A and 3B and used as an optical semiconductor device for receiving an optical signal. The container 11 shown in FIG. 3 is provided with a recess for housing the optical device in the center. The side wall around the recess has a through hole 11a for inserting the optical fiber 7 into and out of the container body 11, and the optical fiber 7 is disposed in the through hole 11a. In addition, an input / output terminal 12 having a wiring conductor 12 a formed so as to conduct inside and outside of the container body 11 is provided on the side wall of the container body 11. Then, an optical device in which the light receiving element 4 is mounted is disposed in the recess, and the optical device is fixed by adjusting so that the optical fiber 7 and the light receiving element 4 are optically coupled, and the optical device and the wiring conductor 12a are connected. Then, a lid is attached so as to close the recess, and an optical semiconductor device for receiving an optical signal is completed.

  The optical device can also be used in an optical semiconductor device for transmitting an optical signal. In this case, the optical device is used for monitoring for monitoring the transmission status of the optical signal. Also in this case, the optical semiconductor device is housed in a container body 11 that is substantially the same as that shown in FIGS. 3A and 3B, and behind the element that transmits the optical signal (the direction opposite to the direction of the optical fiber 7). Alternatively, it is arranged obliquely in front of an element that transmits an optical signal (obliquely forward in the direction of the optical fiber 7), receives light emitted from the element that transmits the optical signal, and monitors the transmission status of the optical transmission element.

  Note that the present invention is not limited to the above-described embodiment, and various modifications may be made without departing from the scope of the present invention.

It is a perspective view which shows one Embodiment about the subcarrier for light receiving elements and optical apparatus concerning this embodiment. It is a perspective view which shows the other example of embodiment of the subcarrier for light receiving elements concerning this embodiment, and an optical apparatus. (A), (b) is a top view which shows the example of the optical semiconductor device which mounted the optical device shown in FIG. 1 inside the package for optical semiconductor element accommodation, respectively.

Explanation of symbols

1: Base 1a: Upper surface 1b: Side surface 1c: Mounting surface 2: Conductor (U-shaped conductor)
4: Light receiving element 5: Resin adhesive 7: Light source (optical fiber)

Claims (8)

A base having a top surface and a side surface, a mounting surface on which the light receiving element is to be mounted on the side surface, and the mounting surface and the optical fiber arranged at a predetermined angle when viewed from above;
A conductor provided on the mounting surface and arranged in a U-shape so as to surround the light receiving element;
Comprising
A subcarrier for a light receiving element, comprising an opening of the U-shaped conductor on one side of the base. 2. The subcarrier for a light receiving element according to claim 1, wherein an opening of the U-shaped conductor is formed on an upper surface side of the base. The light receiving element subcarrier according to claim 1, wherein the conductor extends to an upper surface of the base. 4. The subcarrier for a light receiving element according to claim 1, wherein the conductor is formed thicker sequentially from the light receiving element side to the outside. 5. 5. The subcarrier for a light receiving element according to claim 1, wherein the conductor has an arithmetic average surface roughness Ra defined by JIS B 0601 of 0.2 or more. 6. The subcarrier for a light receiving element according to claim 1, wherein the conductor has a gold film on a surface thereof. The subcarrier for a light receiving element according to claim 1, wherein the base is made of ceramics. A subcarrier for a light receiving element according to any one of claims 1 to 7,
A light receiving element mounted on the mounting surface;
An optical semiconductor device comprising:

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