JP2003347562A - Sub carrier of optical semiconductor device and optical semiconductor device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sub carrier of an optical semiconductor device whereby a wiring conductor layer is formed from the top to the side of an insulation pedestal with enhanced reliability of electrical connection. <P>SOLUTION: The sub carrier comprises an insulation pedestal 1 having a first step 15a and a second step 15b formed by notching a part between the top and the side of an insulation base 13 shaped almost like rectangular parallelepiped, a PD mounting part 14a which is formed on one side of the insulation pedestal 1 and has an optical semiconductor device (PD) 2 joined thereon, a first wiring pattern 14b which is formed from the top of the insulation pedestal 1 via the first step 15a or the second step 15b to one side of the insulation pedestal 1 and is connected to the PD mounting part 14a, and a second wiring pattern 14c which is electrically connected to the optical semiconductor device 2. <P>COPYRIGHT: (C)2004,JPO

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is used in the field of optical communication and the like, and includes a photodiode (PD) and a semiconductor laser (P).
The present invention relates to a subcarrier for mounting an optical semiconductor element such as D) and an optical semiconductor device.

[0002]

2. Description of the Related Art Conventionally, in the field of optical communication, an optical semiconductor device has been used for converting an RF signal into an optical signal and transmitting the signal as an optical signal to an optical fiber or the like.
Devices having a data communication bit rate exceeding bits per second (bps) have been widely used.

FIG. 5 shows a conventional optical semiconductor device having an optical semiconductor element such as a PD or LD. As shown in FIG.
1 is an insulating base (subcarrier) for mounting an optical semiconductor element, 102 is a PD, 103a is a first bonding wire for electrically connecting an upper electrode of the PD 102 and a wiring pattern on the surface of the insulating base 101, 103b is a second bonding wire for electrically connecting the wiring pattern on the surface of the insulating base 101 and the circuit wiring on the circuit board 120. Also, 104
Is an LD, 105 is a submount for mounting the LD, 106 is a temperature measuring element, 107 is a Peltier element, 108 is a base made of ceramics or the like, 108a is a flat bottom plate of the base 108, 108b is a base 1
08 side wall. 109 is a lid made of metal or the like, 1
10 is a cylindrical optical fiber fixing member made of metal or the like (hereinafter, referred to as
Reference numeral 111 denotes an optical fiber; 112, an external lead terminal; and 120, a circuit board on which a control circuit for controlling the PD 102, a line conductor for impedance matching, and the like are formed.

As shown in FIG. 6, the insulating base 101 has a substantially rectangular parallelepiped insulating base material 113 made of ceramics or the like, on which various functional parts made of a conductor layer are formed.
A PD mounting portion 114a made of a conductor layer on which a PD is mounted is formed on one side surface of the third substrate 3, and a first wiring pattern 114b and a second wiring pattern 114c are formed on the upper surface of the insulating base 113. Also, on one side surface of the insulating base material 113, the PD mounting portion 1 is provided.
A connecting portion 114d electrically connecting the first wiring pattern 114b to the first wiring pattern 114b and a bonding portion 114e electrically connected to the second wiring pattern 114c and bonding the first bonding wire 103a are formed. . Further, on the lower surface of the insulating base 113, a bottom plate 108a of the base 108 is provided.
Is formed on the upper surface of the lower conductor layer 114f which is bonded and fixed via an Au-Sn brazing material or the like.

[0005] The PD 102 is a PD mounting portion 114 of the insulating base 101.
a, which is bonded and fixed via an Au-Sn brazing material or the like. PD
The insulating base 101 on which the base 102 is mounted is a bottom plate portion 108a of the base 108.
The light receiving surface of the PD 102 is adhesively fixed to the upper surface of the optical disk so as to be optically coupled to the LD 104 and the optical fiber 111. A submount 105 on which an LD 104 and a temperature measuring element 106 are mounted is provided with a Peltier element
Is placed via.

The optical fiber 111 transmits the light emitted from the LD 104 to the outside and causes the PD 102 to receive the light transmitted from the optical fiber 111 to convert an optical signal into an electric signal. Alternatively, the PD 102 is for monitoring the light emitted backward from the LD 104.

An external lead terminal 112 is fixed to the lower surface of the base 108, and the PD 102, LD 104, temperature measuring element 106, and Peltier element 107 are electrically connected. Also, the base 1
The optical semiconductor device is hermetically sealed by joining the lid body 109 to the upper surface of 08 by a seam welding method or the like.

In this optical semiconductor device, the PD 102 is an insulating base 1
01 is mounted and fixed to the PD mounting portion 114a via a low melting point brazing material made of an Au-Sn alloy or the like. Thereafter, the upper electrode of the PD 102 and the bonding portion 114e are electrically connected via a first bonding wire 103a made of Au, Al, or the like. Then, the insulating base 101 on which the PD 102 is mounted
The lower conductor layer 114f is bonded and fixed to the upper surface of the bottom plate portion 108a of the base 108 via a brazing material made of an Au-Sn alloy, a Pb-Sn alloy, or the like. Thereafter, the first wiring pattern 114b and the second wiring pattern 114c of the insulating base 101 are formed.
To the circuit wiring and the line conductor of the circuit board 120 by using Au or Al
Are electrically connected by a second bonding wire 103b. Similarly, after the LD 104 and the temperature measuring element 106 are bonded and fixed to the upper surface of the submount 105 via a brazing material, the upper surface of the Peltier element 107 is bonded and fixed in advance to the upper surface of the bottom plate 108a of the base 108 via the brazing material. The submount 105 is bonded and fixed via a brazing material.

[0009]

However, in the above-described conventional optical semiconductor device, the insulating base 101 on which the PD 102 is mounted moves while being sandwiched by a transfer jig such as a collet in an assembling process. , Bottom plate 108 of base 108
a, the first wiring pattern
Insulating base material 113 for electrically connecting 114b to connecting portion 114d and second wiring pattern 114c to bonding portion 114e.
Of the first wiring pattern 114b and the connecting portion 114d.
And the second wiring pattern 114c and the bonding portion 114e.
However, there is a problem that the wire breaks or the conduction resistance increases.

The insulating base 101 includes a PD mounting portion 114a,
The connecting portion 114d and the bonding portion 114e are
Are formed at the same time by using a sputtering method, a vacuum evaporation method, a photolithography method, an etching method, or the like. After that, a first wiring pattern 114b and a second wiring pattern 114c are formed,
The formation of these wiring patterns is performed by the PD mounting portion 114a, the connection portion 1
Since this is separate from the formation of the bonding portion 114d and the bonding portion 114e, there is a problem that disconnection easily occurs at a ridge portion where they are electrically connected.

Accordingly, the present invention has been completed in view of the above problems, and an object of the present invention is to provide a wiring conductor layer (wiring pattern) extending from the upper surface to the side surface of an insulating base material by increasing the reliability of electrical connection. It is an object of the present invention to provide an optical semiconductor device provided with an insulating base on which is formed.

[0012]

The subcarrier of the optical semiconductor device of the present invention has first and second steps, each of which is partially cut away, between the upper surface and one side surface of a substantially rectangular insulating base material. An insulating base, a conductor layer formed on the one side surface of the insulating base, to which an optical semiconductor element is bonded, and the first step or the second step from the upper surface of the insulating base. A first wiring conductor layer connected to the conductor layer and a second wiring conductor layer electrically connected to the optical semiconductor element. .

[0013] The subcarrier of the present invention includes a first wiring conductor layer connected to a conductor layer and an optical semiconductor element formed from the upper surface of the insulating base to the side surface via the first step or the second step. Since the second wiring conductor layer that is electrically connected is provided, when the subcarrier is sandwiched and moved by a transport jig such as a collet in an assembling process of the optical semiconductor device, the contact of the transport jig is caused. By doing so, it is possible to prevent the first and second wiring conductor layers from suffering from a disconnection defect, an increase in conduction resistance, and the like. In addition, when the first and second wiring conductor layers are separately formed on the upper surface and the side surface of the insulating base, the ridge between the upper surface and the side surface is not one ridge line (corner) but the first and second wiring conductor layers. Since the steps are formed, the conductor is also formed around the inner surfaces of the first and second steps orthogonal to the upper surface when forming the first and second wiring conductor layers on the upper surface, and on the side surfaces. When the first and second wiring conductor layers are formed, the conductor also extends around the inner surfaces of the first and second steps which are orthogonal to the side surfaces, and thus overlaps the inner surfaces of the first and second steps. As a result, the conductor is formed, and the reliability of the electrical connection is improved at the first and second steps.

An optical semiconductor device according to the present invention comprises: a base having a concave portion formed on the upper surface and having a through hole formed from the concave portion to the outer surface; and a cylindrical optical fiber fixed to the through hole. A member, a subcarrier of the present invention mounted on the bottom surface of the concave portion, and an optical semiconductor bonded to the conductor layer of the subcarrier and electrically connected to the first and second wiring conductor layers An element and a lid joined to the periphery of the concave portion on the upper surface of the base are provided.

The optical semiconductor device of the present invention has high reliability using a subcarrier for mounting an optical semiconductor element having high electrical connection reliability.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A subcarrier and an optical semiconductor device according to the present invention will be described in detail below. FIG. 1 is a cross-sectional view showing an example of an embodiment of an optical semiconductor device of the present invention, FIG. 2 is a perspective view showing an example of an embodiment of a subcarrier of an optical semiconductor element mounted on the optical semiconductor device of the present invention, 3 and 4 are perspective views showing other examples of the embodiment of the subcarrier mounted on the optical semiconductor device of the present invention.

In these figures, reference numeral 1 denotes an insulating base forming a subcarrier, 2 denotes a PD as an optical semiconductor element, and 3a denotes an upper electrode for electrically connecting an upper electrode of the PD 2 and a wiring pattern on the surface of the insulating base 1. One bonding wire 3b is a second bonding wire for electrically connecting the wiring pattern on the surface of the insulating base 1 and the circuit wiring on the circuit board 20;
4 is an LD, 5 is a submount, 6 is a temperature measuring element, 7 is a Peltier element, 8 is a base, 8a is a bottom plate of the base 8, 8b is a side wall of the base 8, 9 is a lid, 10 is a fixing member, 11 is an optical fiber and 12 is an external lead terminal.

Reference numeral 13 denotes a substantially rectangular parallelepiped insulating base constituting the insulating base 1, 14a denotes a PD mounting portion as a conductor layer formed on one side surface of the insulating base 1, and 14b denotes an upper surface of the insulating base 1. A first wiring pattern as a first wiring conductor layer formed on the insulating base 1; a second wiring pattern as a second wiring conductor layer formed on the upper surface of the insulating base 1;
a, a connecting portion that electrically connects the first wiring pattern 14b to the first wiring pattern 14b; 14e, a bonding portion that is electrically connected to the second wiring pattern 14c, to which the first bonding wire 3a is bonded; The lower conductor layer 15a, 15b is bonded and fixed to the upper surface of the bottom plate portion 8a via an Au-Sn brazing material, etc., and the first and second wiring patterns 14b, 14c
Are formed, and the first and second steps are partially cut away.

The first wiring pattern 14b is formed integrally with the PD mounting portion 14a so as to be directly connected to the PD mounting portion 14a. It may be formed separately from the portion 14a and electrically connected by a bonding wire. The second wiring pattern 14c is connected to the PD via the first bonding wire 3a.
2 are electrically connected to electrodes and the like formed on the exposed main surface and light receiving surface.

Reference numeral 20 denotes a circuit board which is electrically connected to the wiring pattern of the insulating base 1 via the second bonding wires 3b. The circuit board 20 has a control circuit for controlling the PD 2 and a line conductor for impedance matching formed thereon, and a circuit wiring and a line conductor are formed on an upper surface thereof. 4b and the second wiring pattern 4c are electrically connected to the circuit wiring and the line conductor of the circuit board 20 by the second bonding wire 3b made of Au, Al or the like.

The subcarrier according to the present invention comprises an insulating base in which a first step 15a and a second step 15b, each of which is partially cut away, are formed between the upper surface and one side surface of a substantially rectangular insulating base material 13. 1
And a conductor layer (PD mounting portion 14a) formed on one side surface of the insulating base 1 and joined to the optical semiconductor element (PD2);
The first step 15a or the second step from the upper surface of the insulating base 1.
A first wiring conductor layer (first wiring pattern 14b) connected to the conductor layer and a second wiring conductor layer (second Wiring pattern 14c).

Further, the optical semiconductor device of the present invention has a base 8 having a concave portion formed on the upper surface and having a through hole formed from the concave portion to the outer surface, and a cylindrical optical fiber fitted into the through hole. The fixing member 10, the subcarrier of the present invention mounted on the bottom surface of the concave portion, and an optical semiconductor element which is bonded to the conductor layer of the subcarrier and electrically connected to the first and second wiring conductor layers. , And a lid 9 joined to the periphery of the concave portion on the upper surface of the base.

In the optical semiconductor device of the present invention, the insulating base 1 on which the PD 2 as an optical semiconductor element is mounted on the upper surface of the bottom plate 8a of the base 8 and the Peltier element 7 are mounted. It has a submount 5 on which the LD 4 and the temperature measuring element 6 are mounted, and is hermetically sealed by attaching a lid 9 to the upper surface of the side wall 8 b of the base 8.

The base 8 comprises a bottom plate 8a and a side wall 8b, and has a recess formed on its upper surface for accommodating various components. The base body 8 may be one in which the bottom plate portion 8a and the side wall portion 8b are integrally formed. A through hole is formed in the side wall portion 8b of the base 8 from the concave portion to the outer surface, and a cylindrical fixing member 10 for fixing the optical fiber 11 is fitted and joined to the through hole.

[0025] In the sub-carrier of the present invention, the insulating substrate 13 is a main portion of the insulating base 1 is made of an insulating material such as ceramics (sintered body), for example, Al ₂ O ₃ sintered material,
Aluminum nitride (AlN) sintered body, silicon carbide (Si
C) Sintered body, silicon nitride (Si ₃ N ₄ ) -based sintered body, glass ceramic sintered body, and the like.

The first and second wiring patterns 14 of the insulating base 1
Each of the conductor layers including b and 14c is formed of, for example, a conductor layer having a three-layer structure in which an adhesion metal layer, a diffusion prevention layer, and a main conductor layer are sequentially laminated. The adhesion metal layer is made of Ti, Cr, Ta, Nb, Ni—Cr alloy, Ta ₂
It is preferable to be made of at least one of N and the like. The thickness of the adhesion metal layer is preferably about 0.01 to 0.2 μm. If it is less than 0.01 μm, it will be difficult to firmly adhere, and if it exceeds 0.2 μm, peeling will easily occur due to internal stress during film formation.

The diffusion preventing layer is formed of Pt, Pd, Rh, Ni, Ni to prevent mutual diffusion between the adhesion metal layer and the main conductor layer.
-It is preferable to be made of at least one of a Cr alloy, a Ti-W alloy and the like. The thickness of the diffusion prevention layer is preferably about 0.05 to 1 μm. If the thickness is less than 0.05 μm, defects such as pinholes are generated and the function as the diffusion prevention layer is hardly achieved. If it exceeds 1 μm, peeling is likely to occur due to internal stress during film formation. When a Ni—Cr alloy is used for the diffusion prevention layer, the adhesion can be ensured, so that the adhesion metal layer can be omitted.

Further, the main conductor layer is made of Au having a small electric resistance,
It is preferably made of Cu, Ni, Ag, etc., and has a thickness of 0.1
About 5 μm is good. If it is less than 0.1 μm, the electrical resistance tends to increase, and if it exceeds 5 μm, peeling is likely to occur due to internal stress during film formation. Further, since Au is a noble metal and expensive, it is preferable to form it as thin as possible from the viewpoint of cost reduction. Since Cu is easily oxidized, a protective layer made of Ni and Au is preferably applied thereon by plating or the like.

A low melting point brazing material for fixing the PD 2 may be applied to the PD mounting portion 14a of the insulating base 1 to a predetermined thickness by a sputtering method or the like. Thereby, PD2
This eliminates the need for arranging a brazing material preform when bonding and fixing the preform. As a low melting point brazing material, Au-
Ge alloy (melting point about 356 ° C), Au-Si alloy (melting point about 370 ° C)
° C), an Au-Sn alloy (melting point of about 183 ° C), an In-Pb alloy (melting point of about 172 ° C), In (melting point of about 157 ° C) and the like are preferable. Since these have a melting point of 400 ° C. or less, the bonding temperature can be lowered. As a result, there is an advantage that the optical semiconductor element is not destroyed by thermal shock. Further, in the assembling process, the low-temperature bonding can be performed, so that the time for raising the temperature and the time for cooling can be shortened. As a result, production costs can be reduced.

The first and second steps 15a, 15b of the insulating base 1
Are formed by a dicing method, a slicing method, a surface grinding method, a sand blast method, or the like.

The first and second steps 15a and 15b correspond to the first and second steps, respectively.
Part of the ridge where the second wiring patterns 14a and 14b are formed
The first and second steps 15a, 15
b on the top surface (the first and second wiring patterns 14
a, the length of 14b in the longitudinal direction) L ₁(FIG. 2) and width (No.
The width in the width direction of the first and second wiring patterns 14a and 14b) L_Two
(FIG. 2) is preferably 0.03 mm or more. If it is less than 0.03 mm,
First and second wirings are provided on the inner surfaces of the first and second steps 15a and 15b.
It becomes difficult to form the patterns 14a and 14b,
As a result, the reliability of the electrical connection decreases. The first and second
Width L of steps 15a and 15b_TwoAre the first and second wiring patterns
It is preferable that the width is equal to or more than の of each width of the pins 14b and 14c.
If it is smaller than 1/2, the first and second steps 15a, 15b
Width of the wiring conductor layer formed on the ridge instead of
The disconnection failure and conduction resistance during the assembly process.
An increase in resistance is likely to occur.

As shown in FIG. 2, the first and second steps 15a and 15b may be composed of two surfaces whose bottom surfaces are orthogonal to each other (surfaces having an L-shaped cross section as viewed from the side). Alternatively, as shown in FIGS. 3 and 4, the bottom surface may be formed of one slope.

As shown in FIGS. 2 and 3, the widths of the first wiring pattern 14b and the second wiring pattern 14c may be wider than the first and second steps 15a and 15b, respectively. Then, as shown in FIG. 4, the first and second steps 15a,
The width of 15b may be wider than the first wiring pattern 14b and the second wiring pattern 14c, respectively. Figure 2
In the case of FIG. 3, the wiring conductor layers are formed on the inner surfaces of the first and second steps 15a and 15b separately by forming conductor layers on the upper surface and the side surfaces of the insulating base 1 separately. The reliability of the electrical connection is improved. In the case of FIG. 4, even if the carrier jig or the like contacts the ridge between the upper surface and the side surface of the insulating base 1 and the ridge is chipped or the like, the wiring conductor layer is not chipped at all. And the reliability of the electrical connection is improved. Also in the case of FIG. 4, the wiring conductor layers can be formed overlapping by separately forming the conductor layers on the upper surface and the side surfaces of the insulating base 1,
This is preferable because the reliability of the electrical connection is further improved.

The first wiring pattern 14b and the second wiring pattern 14c, which are the wiring conductor layers of the present invention, are formed by a thin film forming method such as a sputtering method or a vacuum evaporation method. It is preferable to form wiring conductor layers separately on the side surfaces. In this case, since the ridge between the upper surface and the side surface of the insulating base 1 is not one ridge line (corner) but the first and second steps 15a and 15b are formed, the wiring conductor layer is formed on the upper surface. First and second steps perpendicular to the top surface when forming
The conductors are also formed around the inner surfaces of 15a and 15b, and when forming the wiring conductor layer on the side surfaces, the first and the right sides are orthogonal to the side surfaces.
Since the conductor also extends around the inner surfaces of the second steps 15a and 15b, the conductors are formed overlapping the inner surfaces of the first and second steps 15a and 15b. Step 15
In a and 15b, the reliability of the electrical connection is improved.

The substrate 8 of the present invention is made of an Al ₂ O ₃ sintered body,
Ceramics such as 1N sintered body, mullite sintered body, SiC silicon carbide sintered body, Si ₃ N ₄ sintered body, glass ceramic, or porous tungsten impregnated with Cu, Fe—Ni alloy , Fe-Ni-Co alloy and the like. The bottom plate portion 8a and the side wall portion 8b constituting the base 8 may be formed of the same material or may be formed of different materials. However, when the bottom plate portion 8a and the side wall portion 8b are formed of different materials, it is preferable to select a combination that minimizes the difference in thermal expansion coefficient between the two. Further, the bottom plate portion 8a and the side wall portion 8b may be formed integrally.

A circuit board is provided on the upper surface of the bottom plate 8a of the base 8.
20 and the Peltier element 7 are adhesively fixed. The Peltier element 7 functions as a heat pump for cooling or heating the LD 4 to a predetermined temperature, detects the temperature of the LD 4 measured by the temperature measuring element 6, and cools or heats the LD 4 to a predetermined temperature. . The submount 5 is mounted on the upper surface of the Peltier element 7, and the LD 4 and the temperature measuring element 6 are installed adjacent to the submount 5.

Further, an external lead terminal 12 made of a metal such as an Fe-Ni alloy or an Fe-Ni-Co alloy is provided on the bottom plate 8a or the side wall 8b of the base 8 so as to protrude outside the container. ing. This external lead terminal 12
The inside and outside of the container are separated from each other by being provided so as to penetrate the bottom plate portion 8a or the side wall portion 8b of the base 8 or being joined to a wiring conductor such as a metallized layer led out from the inside of the base 8 to the outside. Electrically connected. The external lead terminals 12 are connected to the circuit board 2 inside the container.
0, the LD 4, the temperature measuring element 6, and the Peltier element 7 are electrically connected.

It should be noted that the present invention is not limited to the above-described embodiment, and that various changes can be made without departing from the scope of the present invention.

[0039]

The subcarrier of the optical semiconductor device according to the present invention is an insulating substrate in which first and second steps are formed by partially cutting out between the upper surface and one side surface of a substantially rectangular insulating substrate. The base, a conductor layer formed on one side of the insulating base, to which the optical semiconductor element is bonded, and a conductor formed from the upper surface of the insulating base to one side via the first step or the second step. By providing a first wiring conductor layer connected to the layer and a second wiring conductor layer electrically connected to the optical semiconductor element, the subcarrier can be transported by collet or the like in the assembly process of the optical semiconductor device. It is possible to prevent the first and second wiring conductor layers from suffering from a disconnection failure, an increase in conduction resistance, and the like due to contact of the transport jig and the like when being moved by being held by the tool. In addition, when the first and second wiring conductor layers are separately formed on the upper surface and the side surface of the insulating base, the ridge between the upper surface and the side surface is not one ridge line (corner) but the first and second wiring conductor layers. Since the steps are formed, the conductor is also formed around the inner surfaces of the first and second steps orthogonal to the upper surface when forming the first and second wiring conductor layers on the upper surface, and on the side surfaces. When the first and second wiring conductor layers are formed, the conductor also extends around the inner surfaces of the first and second steps which are orthogonal to the side surfaces, and thus overlaps the inner surfaces of the first and second steps. As a result, the conductor is formed, and the reliability of the electrical connection is improved at the first and second steps.

The optical semiconductor device of the present invention comprises a base having a concave portion formed on the upper surface and having a through hole formed from the concave portion to the outer surface, a cylindrical optical fiber fixing member fitted into the through hole. A subcarrier of the present invention mounted on the bottom surface of the concave portion, an optical semiconductor element joined to the conductor layer of the subcarrier and electrically connected to the first and second wiring conductor layers, and an upper surface of the base And a lid joined to the periphery of the concave portion described above, thereby achieving high reliability using a subcarrier for mounting an optical semiconductor element having high electrical connection reliability.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating an example of an embodiment of an optical semiconductor device of the present invention.

FIG. 2 is a perspective view showing an example of an embodiment of a subcarrier of the present invention.

FIG. 3 is a perspective view showing another example of the embodiment of the subcarrier of the present invention.

FIG. 4 is a perspective view showing another example of the embodiment of the subcarrier of the present invention.

FIG. 5 is a sectional view showing a conventional optical semiconductor device.

FIG. 6 is a perspective view showing a conventional subcarrier.

[Explanation of symbols]

1: Insulation base 2: PD 4: LD 8: Substrate 9: Lid 10: Optical fiber fixing member 13: Insulating base material 14b: First wiring pattern 14c: Second wiring pattern 15: Step

Claims (2)

[Claims] 1. An insulating base in which first and second steps having a part cut away between an upper surface and a side surface of a substantially rectangular parallelepiped insulating base are formed, and the one side surface of the insulating base. Formed in the
A conductor layer to which an optical semiconductor element is joined, and a first layer connected to the conductor layer formed from the upper surface of the insulating base to the one side surface via the first step or the second step. A subcarrier for an optical semiconductor device, comprising: a wiring conductor layer; and a second wiring conductor layer electrically connected to the optical semiconductor device. 2. A base having a concave portion formed on the upper surface and having a through hole formed from the concave portion to the outer surface, a cylindrical optical fiber fixing member fitted into the through hole, The subcarrier according to claim 1 mounted on a bottom surface, and an optical semiconductor element bonded to the conductor layer of the subcarrier and electrically connected to the first and second wiring conductor layers, An optical semiconductor device, comprising: a lid joined to the periphery of the concave portion on the upper surface of the base.