JP2023164420A - Optical module and manufacturing method thereof - Google Patents

Abstract

To provide a high-speed, large-capacity, and highly reliable optical module that achieves miniaturization and high density, and a manufacturing method thereof.SOLUTION: An optical module includes an optical semiconductor element 10 with an electrode pad 10b formed on its surface, an insulating substrate 30 with electrode pads 30b and 30c formed on its front and back surfaces, and an Au bump 50 that bonds the electrode pad 30b on the back surface of the insulating substrate 30 and the electrode pad 10b of the semiconductor element 10. The back surface of the insulating substrate 30 is arranged to face the front surface of the semiconductor element 10, and the electrode pad 30b on the back surface of the insulating substrate 30 is connected to the electrode pad 30c on the front surface of the insulating substrate 30 via a through hole 30d.SELECTED DRAWING: Figure 2

Description

The present application relates to an optical module and a method for manufacturing the same.

Optical transceivers with built-in optical modules are essential components in optical communication systems, but optical communication networks are required to have higher speeds and larger capacities in order to accommodate data traffic that is increasing year by year. Transmission capacity can be increased by improving the packaging density and characteristics of optical modules, but in order to improve packaging density, it is necessary to miniaturize components within optical modules and to develop high-density packaging technology.

Conventionally, wire bonding has been used to assemble optical semiconductor devices. However, since wire bonding connects the optical semiconductor element and the insulating substrate with wires, it is not possible to stack other members on the surface on which the electrode pads are formed. In addition, a backward wave occurs between the optical semiconductor element and the insulating substrate, resulting in a problem of large characteristic deterioration.

In order to solve this problem, for example, Patent Document 1 describes a flip-chip mounting technology in which an optical semiconductor element is inverted and connected to an insulating substrate using terminals on protrusions called bumps. , a technology using ultrasonic bonding, which is a method that is comprehensively superior in terms of connection pitch accuracy, etc., has been disclosed. In flip-chip mounting using ultrasonic bonding, the optical semiconductor element is generally mounted on the surface of an insulating substrate having a larger projected area than the optical semiconductor element by adsorbing the reversed back side of the optical semiconductor element with a suction collet.

JP 2012-009599 (Paragraphs 0026 to 0029, Figure 2)

However, conventional wire bonding is used for wiring to electrically connect the insulating substrate to the external electronic circuit of the optical module. Apart from this, there is a problem in that it is necessary to secure an area for forming electrode pads for wire bonding to other surrounding members. In addition, in order to fix the optical semiconductor element in the optical module, it is necessary to join it to parts such as a submount with solder, etc., so there is a need to preheat during flip-chip mounting, heat generation due to driving the optical semiconductor element, and surrounding environment due to cooling. There was a problem in that the thermal stress caused by the difference in coefficient of linear expansion with the other members increased, and the reliability of the bump joint was impaired. Furthermore, there is a problem in that stress is generated in the bump joints due to the pressure and vibrations generated during wire bonding to the surface of the insulating substrate mounted on the optical semiconductor element, making the joints liable to break.

The present application was made to solve the above-mentioned problems, and aims to provide an optical module that is compact, high-density, high-speed, large-capacity, and highly reliable, and a method for manufacturing the same. do.

The optical module disclosed in the present application includes a semiconductor element made of InP with electrode pads formed on its surface, an insulating substrate with electrode pads formed on the front and back surfaces, electrode pads on the back surface of the insulating substrate, and electrodes of the semiconductor element. The back surface of the insulating substrate is provided with bumps for bonding to the pads, and the back surface of the insulating substrate is arranged to face the front surface of the semiconductor element, and the electrode pads on the back surface of the insulating substrate are in contact with the electrode pads on the front surface of the insulating substrate through holes. It is characterized by being connected through.

In the method for manufacturing an optical module disclosed in the present application, bumps are provided on the surface of an electrode pad formed on the surface of a semiconductor element made of InP or on the surface of an electrode pad formed on the back surface of an insulating substrate, and the semiconductor placing the insulating substrate on the semiconductor element at a position where the electrode pads of the element and the electrode pads of the insulating substrate face each other; and heating the bumps while the insulating substrate is placed on the semiconductor element. and a step of bonding the bump to the electrode pad of the insulating substrate or the electrode pad of the semiconductor element using ultrasonic waves while applying pressure.

According to the present application, it is possible to achieve miniaturization and high density, and to obtain a high-speed, large-capacity, and highly reliable optical module.

1 is a cross-sectional view showing the configuration of an optical module according to Embodiment 1. FIG. 1 is an enlarged cross-sectional view showing the configuration of an optical module according to Embodiment 1. FIG. FIG. 2 is a top view showing the configuration of a conventional optical module. FIG. 3 is a top view showing another configuration of a conventional optical module. 1 is a top view showing the configuration of an optical module according to Embodiment 1. FIG. FIG. 3 is a top view showing the configuration of an optical module according to Embodiment 2. FIG. FIG. 7 is a top view showing the arrangement of bumps of the optical module according to Embodiment 2 and another optical module. FIG. 7 is a diagram showing the relationship between bump arrangement and stress of the optical module according to Embodiment 2; 7 is a cross-sectional view showing a method for manufacturing an optical module according to a third embodiment. FIG. FIG. 7 is a top view showing an optical module manufacturing method according to a fourth embodiment.

An optical module according to an embodiment will be described below with reference to the drawings. In each figure, the same or similar components are designated by the same reference numerals. In addition, in order to avoid the following explanation from being insufficiently redundant and to facilitate the understanding of those involved, detailed explanations of already well-known matters and duplicate explanations of substantially the same configuration may be omitted. . Furthermore, the contents of the following description and drawings are not intended to limit the subject matter recited in the claims.

Furthermore, the size or scale of each corresponding component is independent between the figures. For example, the size or scale of the same component may be different between a diagram in which a part of the configuration is changed and a diagram in which the configuration is not changed. In addition, regarding the configuration of the optical module, although the implementation includes multiple members, in order to simplify the explanation, only the parts necessary for the explanation will be described, and the explanation of the other parts will be omitted. There is.

Further, in the following description, an optical module will be taken as an example, but each embodiment can also be applied to a semiconductor device that handles electric power and normal current, which have similar problems rather than light.

Embodiment 1.
FIG. 1 is a cross-sectional view showing the configuration of an optical module 1001 according to Embodiment 1 of the present application. FIG. 1(a) is a cross-sectional view of the optical module 1001, and FIG. 1(b) is a cross-sectional view of the optical module 1001 at the AA position in FIG. 1(a). FIG. 2 is an enlarged sectional view of region B in FIG. 1(a).

As shown in FIGS. 1A and 1B, the optical module 1001 includes an optical semiconductor element 10, a submount 20, and an insulating substrate 30 as basic components. The back surface of the optical semiconductor element 10 is bonded to the front electrode pad 20b via the electrode pad 10c with a solder 70, and the surface opposite to the back surface to which the submount 20 of the optical semiconductor element 10 is bonded is insulated. The back surface of the substrate 30 is ultrasonically bonded to the Au bumps 50 via the electrode pads 10b and 30b, respectively. The surface of the insulating substrate 30 is wired with Au wires 60 via electrode pads 30c, and is electrically connected to the outside via an IC 110 bonded to the case 100 with solder 70.

The electrode pad 20c of the submount 20 is bonded to the surface of the thermomodule 40 via metallization 40a with Ag paste 80, and the same surface to which the submount 20 of the thermomodule 40 is bonded has an optical semiconductor. A lens 120 and a multiplexer 130 are bonded to the element 10 at positions corresponding to the laser output direction using a resin adhesive 90, respectively.

The thermo module 40 is housed in a case 100, and the back surface of the thermo module 40 opposite to the surface on which the submount 20 and lens 120 are provided is bonded to the case 100 with Ag paste 80 via metallization 40b. There is.

This will be explained in more detail below. Note that FIG. 1 shows only the basic components of the optical module 1001, and other components such as optical semiconductor elements, ICs, Au wires, capacitors, FPCs, etc. other than those shown are not shown.

The optical semiconductor element 10 corresponds to, for example, an LD (Laser Diode) and a PD (Photo Diode) that convert electrical signals to optical signals and vice versa, and includes, for example, InP, GaAs, GaN, InGaAs, Ge, Si, etc. Consisting of In the first embodiment, a Mach-Zehnder modulator (hereinafter referred to as an MZ modulator) made of InP is used. Although the number of laser light generating parts of the optical semiconductor element 10 is not limited, in the first embodiment, a plurality of laser light generating parts are formed, which makes the effect of the present application more effective. .

Since the optical semiconductor element 10 is electrically and mechanically bonded to the insulating substrate 30 and the Au bumps 50, a A dummy pad is formed of Au metallization.

In the first embodiment, the number of MZ modulators mounted in the optical module 1001 is one, but other optical semiconductor elements whose description is omitted because they are unnecessary for the explanation of this application are also mounted in the optical module 1001. The number of optical semiconductor elements 10 is not limited to one.

As shown in FIG. 1(b), the submount 20 includes a ceramic base material 20a, an electrode pad 20b formed on the front surface of the ceramic base material 20a, and an electrode pad 20c formed on the back surface. The ceramic base material 20a is an electrical insulator, and is preferably made of a material with high thermal conductivity in order to effectively cool the optical semiconductor element 10. Generally, a ceramic plate such as AlN, _{Al2O3 ,} etc. is used. It will be done.

In the first embodiment, the number of submounts 20 mounted on the optical module 1001 is one, but the number of submounts 20 is not limited to one. A plurality of optical semiconductor elements may be bonded to one submount.

Generally, the same material is used for the electrode pads 20b and 20c. The optical semiconductor element 10 is soldered to the electrode pad 20b formed on the circuit surface side using a solder 70, and the electrode pad 20b is connected to surrounding members by forming a joint with an Au wire 60 or the like. It is electrically connected to the surface of the optical semiconductor element 10. Since such an electrode pad 20b is a wiring member for electrically connecting the optical semiconductor element 10 and an external circuit, a metal with low electrical resistance is preferable.

The electrode pads 20b and 20c are generally made of metallized Au or the like with a thickness of about 3.0 μm or less, for example. In the first embodiment, electrode pads 20b made of Au with a thickness of 1.0 μm are metalized on a ceramic base material 20a made of AlN with a thickness of 0.5 mm, and electrode pads 20b made of Au with a thickness of 1.0 μm are metalized at the locations where the optical semiconductor element 10 is soldered. A submount 20 was used in which the electrode pad 20b was pre-coated with AuSn solder 70 having a thickness of 5 μm.

The electrode pad 20c on the back surface corresponding to the heat radiation surface side is mechanically and thermally connected to the inner wall of the case 100 via solder, Ag paste, or the like. In the first embodiment, the connection is made using Ag paste 80.

As shown in FIG. 2, like the submount 20, the insulating substrate 30 includes a ceramic base material 30a, an electrode pad 30b formed on the back surface of the ceramic base material 30a, and an electrode pad 30c formed on the front surface. have The ceramic base material 30a is an electrical insulator, and generally a ceramic plate of AlN, Al ₂ O ₃ or the like is used. Further, in the first embodiment, the insulating substrates 30 mounted on the optical module 1001 are ultrasonically bonded to the optical semiconductor element 10 by the Au bumps 50, but the number of insulating substrates 30 is not limited. It may be one or more.

Generally, the same material is used for the electrode pad 30b and the electrode pad 30c. The electrode pad 30b formed on the back surface of the ceramic base material 30a is bonded to the electrode pad 10b on the front surface of the optical semiconductor element 10 by the Au bump 50, and the electrode pad 30b bonded to the optical semiconductor element 10 is connected to the through hole 30d and the side surface. It is electrically connected to the electrode pad 30c on the surface by metallization or the like. The electrode pad 30c, which is electrically connected to the electrode pad 30b, is further electrically connected to surrounding members by forming a joint with the Au wire 60 or the like. Since such electrode pads 30b and 30c are wiring members for electrically connecting the optical semiconductor element 10 and an external circuit, metals with low electrical resistance are preferably used.

The electrode pads 30b and 30c are generally made of metallized Au or the like with a thickness of about 3.0 μm or less, for example. In the first embodiment, electrode pads 30b and 30c made of Au with a thickness of 1.0 μm are metalized on a ceramic base material 30a made of AlN with a thickness of 0.25 mm. It is electrically connected by a through hole 30d provided in 30a. Further, the electrode pad 30c is electrically connected to the IC 110 by an Au wire 60.

The thermo module 40 transfers the heat received by the heat absorbing section to the heat radiating section via the Peltier element, and releases the heat from the heat radiating section to, for example, the case 100. In this way, the temperature of the optical semiconductor element 10 is controlled by the thermo module 40. This allows the optical semiconductor device 10 to continue stable operation.

As shown in FIG. 1, the thermo module 40 is bonded to the case 100 with Ag paste 80, with the surface to which the submount 20 is bonded as the main surface, and the main surface faces in the positive direction of the Z-axis. Therefore, metallization 40a is formed on the bonding surfaces of submount 20, lens 120, and multiplexer 130 and thermo module 40, and metallization 40b is formed on the bonding surface of case 100 with Ag paste 80.

The same material is generally used for the metallization 40a and 40b. The metallization 40a, 40b is made of, for example, Au having a thickness of about 3.0 μm or less.

The Au bumps 50 electrically and mechanically connect the electrode pads 10b and dummy pads (not shown) formed on the surface of the optical semiconductor element 10 and the electrode pads 30b formed on the back surface of the insulating substrate 30, respectively. , or mechanically connect each other. The material for the Au bumps 50 is preferably a metal with high thermal conductivity. Therefore, Au, Cu, Al, solder, etc. are generally used alone or in combination, and the materials are joined by methods such as heating, pressurization, ultrasonic waves, and soldering.

In the first embodiment, stud bumps formed by cutting wires after first Au wire bonding (ball bonding) are attached to the electrode pads 30b formed on the insulating substrate 30, respectively, are attached to the optical semiconductor element 10 by ultrasonic waves. It is connected to the electrode pad 10b and the dummy pad. Further, an Au wire with a diameter of 25 μm was used, the size of the bump was about 45 μm, and the height to the tip was about 45 μm.

The Au wire 60 electrically connects the electrode pad 30c formed on the surface of the insulating substrate 30 and the electrode pad 20b formed on the surface of the IC 110 and the submount 20, respectively. The material of the Au wire 60 is preferably a metal with low electrical resistance. Therefore, Au, Cu, Al, etc. are generally used alone or in combination, and bonding is mainly performed using ultrasonic waves.

In FIG. 1 of the first embodiment, the electrode pad 30c formed on the insulating substrate 30 and the IC 110, and the IC 110 and the case 100 are bonded by Au wire bonding (ball bonding). Therefore, the Au wire 60 is also used to connect other members whose descriptions are omitted, and the specifications of the Au wire 60 are not limited to two locations.

The solder 70 joins the electrode pad 20b formed on the front surface of the submount 20 and the electrode pad 10c formed on the back surface of the optical semiconductor element 10. When the optical semiconductor element 10 is bonded to the submount 20 by the solder 70, the submount 20 is not yet bonded to the thermomodule 40 by the Ag paste 80. Therefore, the material of the solder 70 is preferably a metal with a melting point higher than the curing temperature of the Ag paste 80 and a high thermal conductivity so that the solder 70 does not re-melt when bonded with the Ag paste 80. Therefore, the solder 70 generally contains Sn, Pb, Au, Ag, Cu, Zn, Ni, Sb, Bi, In, Ge, etc., and is made of an alloy whose melting point is less than 450°C. It is preferable to use an alloy containing Sn, Au, Ag, Cu, etc., and having a melting point of 200° C. or higher. Further, the thickness of the solder 70 is preferably 0.1 mm or less from the viewpoint of tilting and warping of the element. In the first embodiment, a eutectic solder of Sn and Au is used.

The Ag paste 80 adheres the electrode pad 20c formed on the back surface of the submount 20, the metallization 40a formed on the surface of the thermo module 40, and the case 100 to the metallization 40b formed on the back surface of the thermo module 40, respectively. When the submount 20 is bonded to the thermo module 40 using the Ag paste 80, the optical semiconductor element 10 is bonded to the submount 20 using the solder 70. Therefore, it is desirable that the material of the Ag paste 80 has a curing temperature lower than the melting point of the solder 70 and a high thermal conductivity so that the solder 70 does not re-melt when the Ag paste 80 is bonded. For this reason, Ag paste 80 is generally a conductive adhesive containing an organic binder such as epoxy or phenol and a conductive filler made of metals such as Au, Ag, or Cu in the form of spheres or flakes. As long as 70 can be bonded or bonded at a temperature that does not re-melt and has high thermal conductivity, bonding using a metal material such as solder or sintered material, or an insulating adhesive that does not contain metal may be used. In the first embodiment, an Ag paste 80 in which flaky Ag particles are mixed with an epoxy binder is used.

The resin adhesive 90 adheres the lens 120 and the metallization 40a formed on the surface of the thermomodule 40, and the multiplexer 130 and the metallization 40a, respectively. When the respective members are bonded with the resin adhesive 90, the optical semiconductor element 10 is bonded to the submount 20 with the solder 70. Therefore, the resin adhesive 90 is made of a material that has a curing temperature lower than the melting point of the solder 70 so that the solder 70 does not re-melt when the resin adhesive 90 is bonded, and has a viscosity that does not wet and spread around the mounted lens 120 and the lower lens 120. It is desirable to have tackiness to the extent that the multiplexer 130 does not move. It is more preferable to use a resin that can be cured and bonded by a method other than heating such as ultraviolet irradiation. Furthermore, in the first embodiment, there are no conductive paths between the metallization 40a and the lens 120, which are bonded by the resin adhesive 90, and between the metallization 40a and the multiplexer 130, so the resin adhesive 90 It does not need to be conductive.

The case 100 includes a flat bottom portion to which the metallization 40b formed on the back surface of the thermo module 40 is adhered using Ag paste 80, a plurality of side portions connected to the outer edge of the bottom portion, and an opening surrounded by the plurality of side portions. It is a flat box with a section. Further, as shown in FIG. 1, one side of the case 100 is provided with an emission part for guiding the wavelength-multiplexed laser light that is multiplexed by the multiplexer 130 to an optical fiber (not shown).

The lens 120 is made of glass or transparent resin, and focuses the laser light emitted from the optical semiconductor element 10. In the first embodiment, only one lens 120 is illustrated, but a plurality of lenses are mounted in the depth direction of FIG. 1 in accordance with the number of light sources of the optical semiconductor element 10, and the number is not limited to one.

The multiplexer 130 multiplexes the light emitted from the optical semiconductor element 10 and outputs the combined light. The multiplexed light output from the multiplexer 130 is transmitted as a wavelength multiplexed signal on an optical waveguide such as an optical fiber through a lens 120 provided in the case 100.

FIG. 3 is a top view showing the configuration of a conventional optical module. A conventional optical module includes a plurality of optical semiconductor elements 10 in order to increase transmission capacity, and requires many components such as lenses and multiplexers to be mounted. However, since the outer diameter of the optical module case is fixed, high-density mounting technology is required to mount all the mounted components inside the case.

Wire bonding using Au wires 60 has been used to connect the optical semiconductor element 10 and submount 20 and the insulating substrate 30 of the conventional optical module. However, with wire bonding, it is difficult to arrange members one on top of the other, and in addition, a backward wave is generated between the optical semiconductor element 10 and the insulating substrate 30, so there is a concern that the characteristics will be significantly deteriorated.

In order to prevent the occurrence of this backward wave and improve the characteristics while arranging components one on top of the other, a flip-chip mounting technique in which the inverted optical semiconductor element 10 and the insulating substrate 30 are connected using Au bumps 50 is used, especially in terms of cost. , ultrasonic bonding is used, which is a method that is comprehensively superior in terms of connection reliability, bonding load, connection pitch accuracy, etc.

FIG. 4 is a top view showing the configuration of a conventional optical module using flip-chip mounting technology using ultrasonic bonding. In flip-chip mounting using ultrasonic bonding, the reverse side of the optical semiconductor element 10 is generally adsorbed with a collet, and the optical semiconductor element 10 is mounted on the surface of a submount 20 having a larger projected area than the optical semiconductor element 10. However, for example, conventional wire bonding using Au wires 60 is used for wiring from the submount 20 and the insulating substrate 30 to a feed through for electrical connection with an external electronic circuit provided in the case.

Therefore, in addition to the electrode pad 20b connected to the optical semiconductor element 10 on the same surface of the submount 20, it is necessary to form an electrode pad 20b for wire bonding to other surrounding members. Since it has to be formed outside the projected area of the optical semiconductor element 10, as a result, the submount 20 needs to be larger than the optical semiconductor element 10 by at least the area of the electrode pad 20b for wire bonding to other components. . In addition, no other member can be mounted on the reverse side of the optical semiconductor element 10 that has been inverted, that is, within the plane of the optical semiconductor element 10 shown in FIG.

FIG. 5 is a top view showing the configuration of the basic components of the optical module according to Embodiment 1 of the present application. As shown in FIGS. 5 and 2, the optical module 1001 includes an optical semiconductor element 10 in which electrode pads 30b and 30c are formed on both sides of the basic component and are electrically connected to each other by through holes 30d. ing.

With this configuration, not only can the optical semiconductor element 10 be made smaller by eliminating electrode pads for wire bond mounting from the optical semiconductor element 10, as in conventional flip-chip mounting, but also the insulating substrate 30, which is smaller than the optical semiconductor element 10, can be used as an optical semiconductor element. By mounting the optical semiconductor element 10 and the insulating substrate 30 on the element 10, which could only be mounted in the XY directions shown in FIGS. 3 and 4 with the conventional method, the height of the member can be increased by mounting them all in the Z direction. Density can be implemented. In addition, electrode pads 30c for wire bonding to other surrounding components can be formed on the surface of the insulating substrate 30 mounted on the optical semiconductor element 10, which allows components to be densified and bonded to a higher density than conventional flip-chip mounting. Can be made smaller. Further, the surface of the insulating substrate 30 having a smaller projected area than the optical semiconductor element 10 can be attracted by a collet, and the optical semiconductor element 10 can be mounted on the surface.

As described above, according to the optical module 1001 according to the first embodiment, the optical semiconductor element 10 has the electrode pad 10b formed on the front surface, the insulating substrate 30 has the electrode pads 30c and 30b formed on the front surface and the back surface, Au bumps 50 are provided to bond the electrode pads 30b on the back surface of the insulating substrate 30 and the electrode pads 10b of the semiconductor element 10, and the back surface of the insulating substrate 30 is disposed facing the front surface of the semiconductor element 10 and Since the electrode pads 30b on the back surface of the substrate 30 are connected to the electrode pads 30c on the front surface of the insulating substrate 30 via the through holes 30d, the electrode pads for wire bond mounting are eliminated from the optical semiconductor device. The size of can be reduced. Furthermore, by electrically and mechanically bonding the optical semiconductor element and the insulating substrate using Au bumps instead of wire bonding using conventional Au wires, frequency characteristics are improved compared to bonding by wire bonding. can be improved. In addition, by mounting the insulating substrate in the thickness direction of the optical semiconductor element, the area required for mounting the optical semiconductor element, the submount, and the insulating substrate can be reduced, and the density of the optical module can be increased. Therefore, it is possible to obtain a high-speed, large-capacity optical module compared to the conventional one.

Embodiment 2.
In the first embodiment, the Au bumps 50 are arranged evenly within the plane of the insulating substrate 30, but in the second embodiment, a case will be described in which they are arranged at both ends of the insulating substrate 30.

FIG. 6 is a top view showing the configuration of an optical module 1001 according to Embodiment 2 of the present application. As shown in FIG. 6, in the optical module 1001 according to the second embodiment, the Au bumps 50 are arranged in a concentrated manner along both ends of the insulating substrate 30. As shown in FIG.

The basic configuration of optical module 1001 in Embodiment 2 is the same as optical module 1001 in Embodiment 1, but differs only in the arrangement of Au bumps 50 shown in FIG. 6. Therefore, here, the differences will be mainly explained, and the explanation of the same components will be omitted. Note that FIG. 6 illustrates only the optical semiconductor element 10, submount 20, insulating substrate 30, and Au bumps 50 in the optical module 1001 according to the second embodiment, and the explanation of other components is omitted. There is.

In the optical module 1001 of Embodiment 1 and Embodiment 2, thermal stress is generated due to heating during bonding of submount 20 and solder 70, preheating during flip-chip mounting, and heat generated due to driving of optical semiconductor element 10. . Furthermore, thermal stress may be generated due to the difference in coefficient of linear expansion with surrounding members due to cooling. In order to reduce the thermal stress generated at the joints of the Au bumps 50, the number of Au bumps 50 can be increased, and as shown in the first embodiment, the Au bumps 50 can be arranged evenly within the plane of the insulating substrate 30. Possible methods include:

When a plurality of laser beam generating sections are formed in the optical semiconductor element 10 to increase the capacity of the optical module 1001, the plurality of laser beams output from the optical semiconductor element 10 are transmitted through a lens as shown in FIG. The beams are focused by the beam 120 and multiplexed by the multiplexer 130. Therefore, in order to stably output the combined light, it is preferable that the positions of the electrode pads 10b formed on the optical semiconductor element 10 are arranged in a line with respect to the laser light generating section as shown in FIG.

FIG. 7 is a top view showing another arrangement of bumps on the optical module. When forming a plurality of laser light generating sections on one optical semiconductor element 10 in order to increase the capacity of the optical module 1001, after stably outputting multiplexed light, the insulating substrate 30 is connected to the optical semiconductor element 10. When attempting to arrange dummy electrodes for mechanical fixation evenly within the plane of the insulating substrate 30, the electrodes within the plane of the insulating substrate 30 are arranged at one part of the insulating substrate 30, for example, as shown in FIG. 7(a). The Au bumps 50 are lined up in a row at the edge of the side, and the other Au bumps 50 are evenly arranged within the plane of the insulating substrate 30.

In such an arrangement of the Au bumps 50, if thermal stress occurs at the joints of the Au bumps 50, the thermal stress generated at the joints of the Au bumps 50 arranged within the plane of the insulating substrate 30 will be biased. There is a concern that the bonded portion of the Au bump 50, which has the highest thermal stress, may easily peel off.

As a countermeasure, it is possible to increase the number of Au bumps 50, but the load required for flip chip mounting increases according to the increased number of Au bumps 50. Therefore, in the configuration of the second embodiment, the insulating substrate 30 Since vibration occurs between the electrode pad 30c on the surface of the suction collet and the surface of the suction collet, problems such as the electrode pad 30c being deformed due to the large load and contacting the adjacent electrode pad 30c causing a short circuit can occur. may occur. Furthermore, dummy electrode pads 10b are required on the optical semiconductor element 10 in accordance with the increased number of Au bumps 50, which increases the size of the optical semiconductor element 10.

Therefore, in the second embodiment, as shown in FIG. 6, multiplexed light can be stably output to a plurality of laser beam generating sections on the optical semiconductor element 10, and the optical semiconductor element 10 can be outputted without increasing the number of dummy pads. As a method of ensuring the reliability required for the product by uniformly distributing the stress generated at the joints of the Au bumps 50 while the element 10 is miniaturized, the Au bumps 50 are concentrated on both ends of the insulating substrate 30. It was placed as follows.

As a result, compared to the case where the Au bumps 50 are arranged evenly within the substrate as shown in FIG. 7(a), and the case where the Au bumps 50 are arranged along the outer periphery of the substrate as shown in FIG. 7(b), Therefore, it is possible to suppress an increase in thermal stress generated at the bonding portion of a specific Au bump 50 during cooling after flip-chip mounting. FIG. 8 shows the results of stress analysis of the bump arrangement of the optical module according to the second embodiment and other bump arrangements.

Regarding the number and arrangement of the Au bumps 50, unlike the second embodiment in which a plurality of laser light generating parts are formed in the optical semiconductor element 10, the electrode pads 10b are formed in one row. In this case, as long as the Au bumps 50 are arranged so as to face both ends of the insulating substrate 30, there is no problem even if the Au bumps 50 are arranged at other positions on the insulating substrate 30. However, as described above, when the number of Au bumps 50 increases, problems such as a short circuit between the electrode pads 30c formed on the insulating substrate 30 during flip-chip mounting and an increase in the size of the optical semiconductor element 10 may occur. Therefore, the Au bumps 50 are arranged as dummy electrodes on the opposite side to the number of electrode pads 10b arranged in one row according to the number of laser light generating parts formed on the optical semiconductor element 10. It is preferable to place

In addition, as shown in FIG. 1, the insulating substrate 30 mounted on the optical semiconductor element 10 is connected to the IC 110 and the like by Au wires 60 from electrode pads 30c formed on its surface. At this time, in order to shorten the Au wire 60, the electrode pad 30c for bonding the Au wire 60 is preferably formed at the end of the insulating substrate 30. Further, since the Au wire 60 is wire-bonded after the insulating substrate 30 is mounted on the optical semiconductor element 10, stress is generated at the bonded portion of the Au bump 50 due to pressure applied by a tool during wire bonding. Therefore, by arranging the Au bumps 50 intensively on both ends of the insulating substrate 30 as in the second embodiment, it is difficult to bond a specific Au bump 50 during wire bonding onto the electrode pad 30c of the insulating substrate 30. It is possible to suppress peeling of the bonded portion due to stress occurring in the bonded portion.

As described above, according to the optical module 1001 according to the second embodiment, the optical semiconductor element 10 has the electrode pad 10b formed on the front surface, the insulating substrate 30 has the electrode pads 30c and 30b formed on the front surface and the back surface, Au bumps 50 are provided to bond the electrode pads 30b on the back surface of the insulating substrate 30 and the electrode pads 10b of the semiconductor element 10, and the back surface of the insulating substrate 30 is disposed facing the front surface of the semiconductor element 10 and The electrode pad 30b on the back surface of the substrate 30 is connected to the electrode pad 30c on the surface of the insulating substrate 30 via a through hole 30d, and the Au bump 50 is placed near one end of the insulating substrate 30 and near the other end opposite to the one end. Compared to the case where the Au bumps are placed evenly within the plane of the insulating substrate or the case where the Au bumps are placed all around the outer periphery of the board, it is easier to cool down after flip-chip mounting. The thermal stress that occurs and the stress that occurs during wire bonding onto the electrode pad of the insulating substrate after flip-chip mounting is suppressed from peeling due to increase in the bonding area of a specific Au bump, and the optical module is can improve yield and reliability. In addition, since there is no need to place an Au bump in the center of the insulating substrate, the number of Au bumps required to ensure product reliability can be reduced, and the load required during flip-chip mounting can be reduced. . Thereby, it is possible to suppress short circuits caused by deformation of the electrode pads on the surface of the insulating substrate and contact with adjacent electrode pads due to friction with the tip of the suction collet caused by ultrasonic vibration. In addition, by reducing the number of Au bumps required, the number of dummy electrode pads that are only used to mechanically fix the insulating substrate formed on the optical semiconductor element can also be reduced, so the optical semiconductor element can be Can be made smaller. Therefore, it is possible to obtain a highly reliable optical module at a lower cost and with improved yield.

Embodiment 3.
In Embodiment 3, a method for manufacturing optical semiconductor element 10, submount 20, and insulating substrate 30 of optical module 1001 according to Embodiment 1 will be described.

FIG. 9 is a cross-sectional view showing a method for manufacturing an optical module according to the third embodiment. Note that FIG. 9 only illustrates a method for manufacturing the optical semiconductor element 10, submount 20, and insulating substrate 30 in the optical module 1001 of the third embodiment, and includes a process of fixing the thermomodule 40 to the case 100 other than those illustrated. , a process of mounting the assembled optical semiconductor element 10, submount 20 and insulating substrate 30 on the thermo module 40 fixed to the case 100, and a step of mounting the assembled optical semiconductor element 10, submount 20 and insulating substrate 30 on the thermo module 40 fixed to the case 100, and connecting the wire from the electrode pad 30c of the insulating substrate 30 mounted on the thermo module 40 to the IC 110. Other assembly processes of the optical module 1001, such as the bonding process and the process of mounting the lens 120 and the multiplexer 130 between the laser light generation part formed on the optical semiconductor element 10 and the emission part of the case 100, are performed using conventional methods. Since it is similar to the optical module, illustration is omitted.

First, as shown in FIG. 9(a), the submount 20 is placed on a hot plate 200 heated to 280° C. or higher, which is the melting point of the AuSn solder 70, and the submount 20 is placed on the electrode pad 20b of the submount 20. By melting the pre-coated AuSn solder 70, it is soldered to the optical semiconductor element 10.

At this time, the optical semiconductor device 10 may be placed on the submount 20 after confirming that the AuSn solder 70 has melted, or may be placed before the AuSn solder 70 has melted, but the submount 20 may be placed on the submount 20 in a smaller size. In order to increase It is preferable to mount the optical semiconductor element 10 after confirming that the AuSn solder 70 has melted. Further, in the third embodiment, the heating temperature of the hot plate 200 was set to 340°C.

Next, as shown in FIG. 9B, the submount 20 to which the optical semiconductor element 10 is die-bonded is placed on the stage 300 of an ultrasonic mounting machine. At this time, the stage 300 of the ultrasonic mounting machine is preheated to 200° C., which is a temperature lower than the melting point of the AuSn solder 70, in order to improve the bondability of the Au bumps 50. In addition, the submount 20 placed on the stage 300 is vacuumed and adsorbed onto the stage 300, and the jigs 300a and 300b are used to machine the side surfaces of the submount 20 on both sides in the direction in which ultrasonic vibration is applied. The submount 20 is fixed so that it does not move in the direction of ultrasonic vibration.

Further, as shown in FIG. 9(c), Au bumps 50 are formed in advance on the electrode pads 30b of the insulating substrate 30 at positions corresponding to the electrode pads 10b on the optical semiconductor element 10, and A suction collet 400 of an ultrasonic mounting machine adsorbs the surface on which 30c is formed, and transports it to a predetermined position on the optical semiconductor element 10 that has been preheated to 200°C. The insulating substrate 30 is placed on the optical semiconductor element 10 at a position where the electrode pad 30b on which the Au bump 50 of the insulating substrate 30 is formed is opposed to each electrode pad 10b corresponding to the electrode pad 30b of the optical semiconductor element 10. place Note that in the third embodiment, the Au bumps 50 are formed on the electrode pads 30b, but the Au bumps 50 may be formed in advance on the electrode pads 10b of the optical semiconductor element 10.

Thereafter, as shown in FIG. 9D, the insulating substrate 30 adsorbed by the adsorption collet 400 is placed on the optical semiconductor element 10 and pressurized. At this time, while it is a common process to apply ultrasonic vibration immediately after pressurization to bond the optical semiconductor element 10 and the Au bumps 50, in the third embodiment, the suction collet 400 is The Au bumps 50 are also heated to 200° C., which is the same temperature as the optical semiconductor device 10, by preheating in advance or by continuing to press the insulating substrate 30 onto the optical semiconductor device 10 via the Au bumps 50.

Finally, as shown in FIG. 9(e), the submount 20 is mechanically fixed using jigs 300a and 300b while the Au bump 50 is heated to about 200° C. like the optical semiconductor element 10. The optical semiconductor element 10 and the Au bumps 50 are ultrasonically bonded by applying ultrasonic vibrations in the direction (direction C) using an ultrasonic mounting machine.

In this way, by heating the Au bump 50 to the same temperature as the optical semiconductor element 10 and performing ultrasonic bonding, better bonding can be obtained with lower load, lower amplitude, and in a shorter time than bonding at room temperature. Therefore, the optical semiconductor element 10 can be prevented from being destroyed by the ultrasonic waves applied during bonding. In addition, the Au bumps 50 absorb thermal stress generated at the joints of the Au bumps 50 when the assembled optical semiconductor device 10, submount 20, and insulating substrate 30 are removed from the stage 300 of the ultrasonic mounting machine and cooled. Since the size can be reduced compared to the case where the bonding is performed at room temperature without heating, it is possible to prevent the bonding portions of the Au bumps 50 from peeling off due to heating and cooling applied after flip-chip mounting, thereby preventing the optical module 1001 from breaking. Furthermore, by die-bonding the optical semiconductor element 10 to the submount 20 in the pre-process of flip-chip mounting, there is no need to directly mechanically fix the optical semiconductor element 10 during flip-chip mounting. can be prevented from being destroyed due to contact with fixing jigs, etc.

In the third embodiment, the optical semiconductor element 10 was die-bonded to the submount 20 and then placed on the stage of an ultrasonic mounting machine, and the insulating substrate 30 was flip-chip mounted with the submount 20 fixed. However, the order in which the optical semiconductor element 10, submount 20, and insulating substrate 30 are assembled is not limited to this. For example, the optical semiconductor element 10 is placed on the stage of an ultrasonic mounting machine, the optical semiconductor element 10 is directly fixed, the insulating substrate 30 is flip-chip mounted, and then the optical semiconductor element 10 is flip-chip mounted. The element 10 may be die-bonded to the submount 20. However, when mechanically fixing the side surfaces of the optical semiconductor element 10 using a jig or the like, the fixing is necessary to prevent the laser beam generating part of the optical semiconductor element 10 from being destroyed by the ultrasonic vibrations applied during flip-chip mounting. It is necessary to set the fixing direction using ultrasonic vibration and a jig so that the tool does not touch the laser beam generating portion of the optical semiconductor element 10. For example, when the laser beam generating portion is formed on the side surface of the short side of the optical semiconductor element 10, both sides of the long side of the optical semiconductor element 10 are fixed with a jig. It is necessary to perform flip-chip mounting so that the insulating substrate 30 vibrates with respect to the long side of the optical semiconductor element 10.

When the insulating substrate 30 is flip-chip mounted before the optical semiconductor element 10 is die-bonded to the submount 20, the bonded portion of the Au bump 50 receives thermal stress due to heating and cooling during die-bonding to the submount 20. However, if the insulating substrate 30 is flip-chip mounted before die-bonding the optical semiconductor element 10 to the submount 20, the optical semiconductor element 10 may be tilted due to the difference in thickness of the AuSn solder 70 pre-coated on the submount 20. It is possible to eliminate the influence of warping due to thermal stress during die bonding. As a result, ultrasonic waves are applied with only the specific Au bumps 50 in contact with the optical semiconductor element 10, so that the insulating substrate 30 rotates during flip-chip mounting, and the specific Au bumps 50 are crushed after flip-chip mounting. It is possible to prevent the optical semiconductor element 10 from being destroyed due to excessive damage.

As described above, according to the method for manufacturing the optical module 1001 according to the third embodiment, the electrode pads 10b formed on the surface of the optical semiconductor element 10 or the electrode pads formed on the back surface of the insulating substrate 30 Au bumps 50 are provided on the surface of the optical semiconductor element 30b, and the insulating substrate 30 is placed on the optical semiconductor element 10 at a position where the electrode pad 10b of the optical semiconductor element 10 and the electrode pad 30b of the insulating substrate 30 face each other; A step of heating the Au bumps 50 with the insulating substrate 30 placed on the optical semiconductor element 10, and applying ultrasonic waves while applying pressure to the electrode pads 30b of the insulating substrate 30 or the electrode pads 10b of the optical semiconductor element 10 and the Au bumps 50. Since this method includes the step of bonding, it is possible to obtain a good bonding condition with lower load, lower amplitude, and in a shorter time than bonding at room temperature. You can prevent it from being destroyed. In addition, when the assembled optical semiconductor element, submount, and insulating substrate are removed from the stage of the ultrasonic mounting machine and cooled, the stress generated at the Au bump joint can be reduced by reducing the temperature difference between the optical semiconductor element and the Au bump. Since the size can be reduced compared to the case where they are bonded in a certain state, it is possible to prevent the bonded portions of the Au bumps from peeling off due to heating and cooling applied after flip-chip mounting and breakage of the optical module. Therefore, a highly reliable optical module with improved yield can be obtained.

Embodiment 4.
In Embodiment 4, a method for manufacturing optical semiconductor element 10, submount 20, and insulating substrate 30 of optical module 1001 according to Embodiment 2 will be described.

FIG. 10 is a top view showing a method for manufacturing an optical module according to Embodiment 4. The basic manufacturing process of the optical module 1001 in the fourth embodiment is the same as the manufacturing method of the optical module 1001 in the third embodiment, except for the flip-chip mounting process of the insulating substrate 30 shown in FIG. Therefore, here, we will mainly explain the differences, and omit the explanation of the same manufacturing steps. Note that FIG. 10 only illustrates a method of flip-chip mounting the insulating substrate 30 on the optical semiconductor element 10 die-bonded to the submount 20 in the optical module 1001 using an ultrasonic mounting machine, and other assembly steps are not illustrated or explained. is omitted.

In the third embodiment, since the Au bumps 50 are arranged evenly within the plane of the insulating substrate 30, the ultrasonic vibration during flip-chip mounting with respect to the arrangement of the Au bumps 50 poses no problem regardless of the direction. . On the other hand, in the fourth embodiment, since the Au bumps 50 are arranged in a concentrated manner in one row on both ends of the insulating substrate 30, the rows of Au bumps 50 are The difference from the third embodiment is that the ultrasonic vibration is applied in a direction perpendicular to the third embodiment.

In the optical module 1001 according to the fourth embodiment, Au bumps 50 are arranged in one row on each side of both ends of the insulating substrate 30. Therefore, when ultrasonic waves are applied in the same direction as the rows of Au bumps 50, the Au bumps 50 placed at both ends of the rows are bonded first, suppressing vibrations caused by the ultrasonic waves, and It is conceivable that the bonding properties of the Au bumps 50 placed in the area may deteriorate. As a result, if stress is generated at the joints of the Au bumps 50, the joints of the Au bumps 50 placed in the center of the row, which have lower bonding properties than the ends of the row, will peel off, causing the optical module 1001 to break. There are concerns.

Therefore, in the fourth embodiment, as shown in FIG. 10, the bonding properties of the Au bumps 50 arranged in one row on both ends of the insulating substrate 30 are made to be uniformly good. As a method for ensuring the reliability required for the product while reducing the size of the optical semiconductor device 10, ultrasonic waves were applied in the direction perpendicular to the rows of the Au bumps 50 arranged (direction D). By doing this, all the Au bumps 50 arranged in the direction of vibration caused by the ultrasonic wave are located at both ends, so that by joining a specific Au bump 50 first, other Au bumps 50 This suppresses deterioration of the bonding properties of the Au bumps 50 and prevents the optical module 1001 from being broken due to peeling of the bonded portions of the Au bumps 50 compared to the case where ultrasonic waves are applied in the same direction as the rows of the Au bumps 50. can improve product reliability.

In the third embodiment, the order of assembling the optical semiconductor element 10, the submount 20, and the insulating substrate 30 is such that the insulating substrate 30 is flip-chip mounted to the optical semiconductor element 10, and then the insulating substrate 30 is flip-chip mounted. The optical semiconductor element 10 could also be die-bonded to the submount 20. However, in the fourth embodiment, the order of assembling the optical semiconductor element 10, submount 20, and insulating substrate 30 is to die-bond the optical semiconductor element 10 to the submount 20, and then place it on the stage of an ultrasonic mounting machine. It is preferable to perform flip-chip mounting of the insulating substrate 30 with the submount 20 fixed.

For example, when mechanically fixing the side surfaces of the optical semiconductor element 10 using a jig or the like, it is possible to mechanically sandwich the side surfaces on both sides of the direction in which ultrasonic vibrations are applied and move the optical semiconductor element 10 in the direction of ultrasonic vibration. 10 must be fixed so that it does not move. Then, ultrasonic vibration is applied in the direction in which the optical semiconductor element 10 is mechanically fixed, which in the fourth embodiment is perpendicular to the row in which the Au bumps 50 are arranged, to bond the optical semiconductor element 10 and the Au bumps. 50 are ultrasonically bonded. At this time, as shown in Embodiment 2, the optical semiconductor element 10 in which a plurality of laser beam generating parts are formed has electrode pads 10b formed on the optical semiconductor element 10 arranged in a row with respect to the laser beam generating parts. It is preferable to arrange the Au bumps 50 side by side, and one side of the row of Au bumps 50 arranged on the insulating substrate 30 is arranged at a place where it can be bonded to the electrode pad 10b. Therefore, it is preferable that the plurality of laser beam generating parts be formed on the side surface in the direction perpendicular to the electrode pad 10b of the optical semiconductor element 10, that is, the row in which the Au bumps 50 are arranged.

Therefore, when the insulating substrate 30 is flip-chip mounted before the optical semiconductor element 10 is die-bonded to the submount 20, the laser beam generating part of the optical semiconductor element 10 is formed in the optical module manufacturing method according to the fourth embodiment. The side surfaces must be clamped and fixed with jigs or the like during flip-chip mounting, and there is a concern that the laser light generating portion of the optical semiconductor element 10 may be destroyed by the ultrasonic vibrations applied during flip-chip mounting.

For the above reasons, in the fourth embodiment, the optical semiconductor element 10 is die-bonded to the submount 20 and then placed on the stage of an ultrasonic mounting machine, and the laser beam generating part of the optical semiconductor element 10 is formed using a jig. With the side surface of the submount 20 in the direction in which the submount 20 is mechanically fixed, ultrasonic vibration is applied in the direction in which the submount 20 is mechanically fixed, and the optical semiconductor element 10 and the Au bumps 50 are It is preferable to perform flip-chip mounting of the insulating substrate 30 by ultrasonic bonding.

As described above, according to the method for manufacturing the optical module 1001 according to the fourth embodiment, the electrode pads 10b formed on the surface of the optical semiconductor element 10 or the electrode pads formed on the back surface of the insulating substrate 30 Au bumps 50 are provided on the surface of the optical semiconductor element 30b, and the insulating substrate 30 is placed on the optical semiconductor element 10 at a position where the electrode pad 10b of the optical semiconductor element 10 and the electrode pad 30b of the insulating substrate 30 face each other; A step of heating the Au bumps 50 with the insulating substrate 30 placed on the optical semiconductor element 10, and applying ultrasonic waves while applying pressure to the electrode pads 30b of the insulating substrate 30 or the electrode pads 10b of the optical semiconductor element 10 and the Au bumps 50. bonding step, the Au bumps 50 are arranged near one end of the insulating substrate and near the other end opposite to the one end, and when performing ultrasonic bonding, the Au bumps 50 are placed in a direction perpendicular to one end of the insulating substrate 30. Since ultrasonic vibrations are applied to the bonding process, certain Au bumps are bonded first with a lower load, lower amplitude, and in a shorter time than bonding at room temperature, and the bondability of other Au bumps decreases. It is possible to obtain a good bonding state with all the arranged Au bumps, and it is possible to suppress destruction of the optical semiconductor element due to the load and amplitude applied during ultrasonic bonding. In addition, the thermal stress generated at the junction of the Au bumps due to heating and cooling of the optical module described in Embodiment 3 is reduced compared to when the optical semiconductor element and the Au bumps are joined under a temperature difference. Therefore, it is possible to obtain the effect of suppressing breakage of the optical module due to peeling of the bonded portion of the Au bumps after flip-chip mounting. Furthermore, since the number of Au bumps required to ensure the reliability of the product described in Embodiment 2 can be reduced, the electrode pad on the surface of the insulating substrate is deformed due to friction with the tip of the suction collet caused by ultrasonic vibration. This reduces the number of dummy electrode pads that only mechanically fix the insulating substrate formed on the optical semiconductor element. It is also possible to obtain the effect of miniaturizing the spectroscopic semiconductor element. Therefore, it is possible to obtain a highly reliable optical module at a lower cost and with improved yield.

Although this application describes various exemplary embodiments and examples, various features, aspects, and functions described in one or more embodiments may be applicable to a particular embodiment. The present invention is not limited to, and can be applied to the embodiments alone or in various combinations. Accordingly, countless variations not illustrated are envisioned within the scope of the technology disclosed herein. For example, this includes cases where at least one component is modified, added, or omitted, and cases where at least one component is extracted and combined with components of other embodiments.

Reference Signs List 10 optical semiconductor element, 10b electrode pad, 30 insulating substrate, 30b, 30c electrode pad, 30d through hole, 50 Au bump, 1001 optical module.

Claims (15)

A semiconductor element made of InP with electrode pads formed on its surface, an insulating substrate having electrode pads formed on its front and back surfaces, and a bump that connects the electrode pads on the back surface of the insulating substrate and the electrode pads of the semiconductor element. The back surface of the insulating substrate is arranged to face the front surface of the semiconductor element, and
An optical module characterized in that an electrode pad on the back surface of the insulating substrate is connected to an electrode pad on the front surface of the insulating substrate via a through hole. 2. The optical module according to claim 1, wherein the semiconductor element is bonded to a surface of a submount via solder. 2. The optical module according to claim 1, wherein the area of the surface of the insulating substrate on which the electrode pad is formed is smaller than the area of the surface of the semiconductor element on which the electrode pad is formed. 2. The optical module according to claim 1, wherein the bumps are arranged evenly within a plane of the insulating substrate. 2. The optical module according to claim 1, wherein the bumps are arranged at an edge of one end of the insulating substrate connected to the outside and an edge of the other end opposite to the one end. 6. The optical module according to claim 5, wherein the bump disposed on the edge of the other end is a dummy. The semiconductor element includes a laser beam generating section,
7. The optical module according to claim 5, wherein the laser beam generating section is provided on a side surface of the semiconductor element in a direction perpendicular to the one end. A bump is provided on the surface of an electrode pad formed on the surface of a semiconductor element made of InP or on the surface of an electrode pad formed on the back surface of an insulating substrate, and the electrode pad of the semiconductor element and the electrode pad of the insulating substrate are connected. a step of placing the insulating substrate on the semiconductor element at opposing positions;
heating the bumps while the insulating substrate is placed on the semiconductor element;
a step of bonding the electrode pad of the insulating substrate or the electrode pad of the semiconductor element and the bump using ultrasonic waves while applying pressure;
A method for manufacturing an optical module, comprising: The back surface of the insulating substrate is arranged to face the front surface of the semiconductor element, and
9. The method of manufacturing an optical module according to claim 8, wherein the electrode pad on the back surface of the insulating substrate is connected to the electrode pad on the front surface of the insulating substrate via a through hole. 9. The method of manufacturing an optical module according to claim 8, wherein the area of the surface of the insulating substrate on which the electrode pad is formed is smaller than the area of the surface of the semiconductor element on which the electrode pad is formed. . 11. The method of manufacturing an optical module according to claim 8, wherein the bumps are arranged evenly within a plane of the insulating substrate. 11. The bumps are arranged at an edge of one end of the insulating substrate connected to the outside and an edge of the other end opposite to the one end. A method for manufacturing an optical module according to. 13. The method of manufacturing an optical module according to claim 12, wherein the bump disposed on the edge of the other end is a dummy. 13. The method of manufacturing an optical module according to claim 12, wherein when the ultrasonic bonding is performed, the ultrasonic vibration is applied in a direction perpendicular to the one end. The semiconductor element includes a laser beam generating section,
13. The method of manufacturing an optical module according to claim 12, wherein the laser beam generator is provided on a side surface of the semiconductor element in a direction perpendicular to the one end.

Images