JP2003309314A - Integrated optical element and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an integrated optical element, which inexpensively constitutes a package, and which can simultaneously perform a high position accuracy and a high heat sink efficiency, while suppressing an increase in manufacturing cost with simple steps, and to provide a method for manufacturing the same. <P>SOLUTION: The integrated optical element 10 comprises at least a light- emitting element 14 adhered onto a lead frame 11 via a sub-mount 13. In this element 10, the sub-mount 13 is adhered to the lead frame 11 via a solver 12 embedded in the recess 11A formed on the frame 11. The method for manufacturing the same comprises the steps of forming the recess 11A on the lead frame 11, supplying the solder 12 to the recess 11A, mounting the sub-mount 13 on the solder 12, and completing the adhesion of the solder 12 through heat treating. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an integrated optical element having at least a light emitting element and having the light emitting element bonded to a lead frame directly or through a submount, and a method of manufacturing the same. It is suitable for application to a display device typified by a laser display and an integrated optical element used in a communication device for coupling with an optical fiber.

[0002]

2. Description of the Related Art For example, CD (compact disc), M
In an optical disc device for an optical disc such as a D (mini disc), a DVD (digital video disc or a digital versatile disc), an integrated optical element used for the optical pickup or the like is, for example, a light emitting element, a light receiving element, a lens, on a lead frame, An optical component such as a prism is mounted and configured.

FIG. 13 shows a sectional view of an integrated optical element using a conventional lead frame. As shown in FIG. 13, a light emitting element 51 made of, for example, a semiconductor laser is mounted on a submount 52, and the submount 52 is attached to a lead frame 54. A semiconductor device such as silicon may be used as the submount 52. In many cases, this semiconductor device has a detector function for monitoring the emission intensity of a semiconductor laser and further has an arithmetic circuit built therein. Further, in the case where a plurality of lenses (not shown), a diffraction grating, a multi-lens in which a HOE (holographic optical element) is built, a compound prism formed by laminating a plurality of optical glasses or quartz plates, etc. are mounted. There is also.

The lead frame 54 is made up of the light emitting element 5
It plays the role of a package for the integrated optical element such as 1. Generally, ceramics and lead frames are used for the package, but from the viewpoint of price, currently, inexpensive lead frames are used except for special cases.

By the way, when the submount 52 having the integrated optical element mounted thereon is bonded to the lead frame 54, the lead frame 54 and the submount 52 must be accurately aligned. Also, the lead frame 5
An adhesive for No. 4 such as Ag paste or solder needs to be heated at the time of bonding because the bonding is completed by heating.

Therefore, the submount 52 having the integrated optical element mounted thereon is adhered to the lead frame 54 as follows. First, an adhesive such as an Ag paste 53 is applied to a predetermined position on the lead frame 54. After that, the integrated optical element, for example, the light emitting element 51 is positioned based on an appropriate mark position, and this is arranged on the Ag paste 53 applied on the lead frame 54.
Further, heat treatment is performed to complete the adhesion of the Ag paste 53.

It is desirable that a device for aligning the lead frame 54 and the submount 52 (hereinafter referred to as a positioning device) and a device for performing heat treatment be separately configured.
This is because when the positioning machine heats, the heating causes deformation such as expansion of the lead frame and the device, resulting in displacement of the position or a long processing time. That is, the lead frame 54 and the submount 52 on which the light emitting element 51 and the like are mounted are aligned by the positioning machine. Then, it is transferred from the positioning machine to a heat treatment device (hereinafter referred to as a heating machine). Next, the plurality of integrated optical elements are collectively heat-treated in a heater to complete the adhesion.

Conventionally, the lead frame 54 and the light emitting element 5
1 is usually attached to the submount 52 on which Ag is mounted.
Paste 53 is used. This is because the Ag paste 53 is in a paste state in an uncured state, so that the surface accuracy of the Ag paste 53 can maintain the positional accuracy of the light emitting element 51 and the lead frame 54 when the Ag paste 53 is transferred from the positioning machine to the heating machine. Is. That is, as shown in FIG. 14A, the Ag paste 53 wets and spreads from the side surface of the submount 52 to the surface of the lead frame 54 to form a fillet. At this time, due to the surface tension of the Ag paste 53,
Since a force indicated by a thick arrow acts on the submount 52, the positional accuracy between the light emitting element 51 and the lead frame 54 can be maintained by fixing the submount 52. The state of the fillet depends on the atmospheric pressure, the viscosity of the Ag paste 53,
It is also determined by the wettability (spreading) on the lead frame 54.

On the other hand, the lead frame 54 includes the light emitting element 5
In addition to housing 1 and the light receiving element, it also has a role of radiating heat that efficiently releases heat generated from electrically operated components such as the light emitting element 51 and the light receiving element. That is, as shown in FIG. 14B, heat generated from the light emitting element 51 is transferred to the submount 5
2 and Ag paste 53, lead frame 54
It can be released by radiating heat to.

[0010]

By the way, in the field of an optical recording medium such as an optical disc, the recording density of the medium,
In order to improve the transfer rate, there is an increasing demand for higher light output and shorter wavelength of light emitting devices. Increasing the light output of the light emitting element or shortening the wavelength of light in this way means that the driving power of the light emitting element is increased, and at the same time, the amount of heat generated from the light emitting element is increased.

That is, as shown in FIG. 15A, in the semiconductor laser, the optical output-current characteristic (LI characteristic) is such that the optical output is small up to a certain current value (below the threshold value), and the current beyond that. At value, the light output increases with increasing current. In the voltage-current characteristic (VI characteristic), the rate of increase in voltage is large when the current is small, and the rate of voltage increase is small when the current is large, but the voltage is large as the current is large. Here, the high light output L shown in FIG. 15A
Consider the case of high and low optical output Llow in comparison. At this time, since Llow <Lhigh, L-
From the I characteristic, Ilow <Ihigh for the current. Furthermore, from the VI characteristic, Vlow <
It becomes Vhigh. Since the drive power P is P = I × V, Plow <Phigh. Therefore, it is understood that the drive power P increases as the light output L increases.

FIG. 15B shows the relationship between the wavelength and the general drive voltage V of the light emitting element. Wavelength 78 for CD and MD
At 0 nm, the drive voltage is 1.8 V and the wavelength is 650 for DVD.
The driving voltage is 2.5 V in nm and the wavelength is 40
When it is shortened to 0 nm, the driving voltage becomes 5.5V. Therefore, the shorter the wavelength is, the larger the driving voltage V is.
It can be seen that the driving power P also increases.

However, since the Ag paste is an organic adhesive in which silver particles are dispersed, its thermal conductivity is smaller by one digit or two digits than that of solder. That is, since the Ag paste is inferior in heat conduction performance to solder, the heat generated during the operation of the light emitting element cannot be sufficiently dissipated.
It is possible that the temperature of the light emitting element (semiconductor laser chip) rises.

In particular, since the amount of heat generated becomes large due to the high light output and the short wavelength as described above, it is difficult to meet the demands for the high light output and the short wavelength of the light emitting device in the structure in which the bonding is performed by the Ag paste. Is.

Further, as the recording density of the optical disc is increased, it is required to increase the positioning accuracy. That is, in order to increase the recording density, the numerical aperture NA of the objective lens increases and so-called lateral magnification and vertical magnification increase, so that it is necessary to increase the positional accuracy of the light emitting point of the light emitting element.

When solder is used as an adhesive between the lead frame and the submount on which the light emitting element is mounted or the light emitting element, the form of the solder to be supplied and the positioning accuracy are lowered. Is a problem.
When the Ag paste is adhered as described above, the positioning can be performed with an accuracy of ± 5 μm or more.

Conventionally, there are thread-like solder, cream-like solder, and sheet-like solder in the form of solder. They are,
Although there is a difference in the shape, it is common that it spreads on the lead frame when heated, and the spread amount is determined by the heating temperature, the time, and the supply amount of solder. That is, since the solder spreads on the lead frame, the tilt direction of the light emitting element that is positioned and temporarily placed on the lead frame,
Horizontal and vertical movements occur. Since the amount of movement is determined by the amount of spread of the solder, the amount of movement during heating is added to the temporary placement accuracy (positioning accuracy) in the positioning machine. Therefore, the positional accuracy is inferior to that of the conventional Ag paste.

Further, there is one in which minute solder bumps are formed on the lead frame when the lead frame and other components are bonded. When forming such solder bumps, a mask is placed on the lead frame, and solder is supplied by a method such as a vapor deposition method, a plating method, or a screen printing method. For example, in the vapor deposition method, it is possible to achieve high positional accuracy of about 1 μm by a method of performing vapor deposition after masking using photolithography. However, this method has a drawback that the number of steps is increased and the manufacturing cost is increased. For example, in the plating method, masking for ensuring the positional accuracy is required, and thus the manufacturing cost is also increased by this step. For example, the screen printing method has a drawback in that the positional accuracy is deteriorated (about 100 μm) due to printing bleeding.

Therefore, the method of forming solder bumps is not suitable for attaching a light emitting element mounted submount or a light emitting element onto a lead frame.

In order to solve the above-mentioned problems, in the present invention, it is possible to construct a package at a low cost and simultaneously achieve high positional accuracy and high heat radiation efficiency while suppressing an increase in manufacturing cost by a simple process. An integrated optical element and a method for manufacturing the same are provided.

[0021]

The integrated optical element of the present invention is formed by bonding at least a light emitting element directly or through a submount on a lead frame, and a recess is formed in the lead frame and embedded in the recess. The lead frame is bonded to the light emitting element or submount by soldering.

According to the above-described structure of the integrated optical element of the present invention, the lead frame is provided with the recess, and the lead frame is adhered to the light emitting element or the submount by the solder embedded in the recess. The spread of the solder in the heat treatment for adhesion can be restricted by the concave portion of the lead frame. This makes it possible to maintain high positional accuracy between the light emitting element and the lead frame when manufacturing the integrated optical element having this configuration. In addition, since they are adhered by solder, the heat from the light emitting element can be efficiently dissipated as compared with the case where they are adhered by Ag paste.

The integrated optical element of the present invention is formed by adhering at least a light emitting element directly or via a submount on a lead frame, a through hole is formed in the lead frame, and a solder embedded in the through hole. The light emitting element or the submount and the lead frame are adhered by the above.

According to the above-mentioned structure of the integrated optical element of the present invention, the lead frame is provided with the through hole, and the light emitting element or the submount is bonded to the lead frame by the solder embedded in the through hole. Therefore, the spread of the solder in the heat treatment for adhesion can be restricted by the through hole of the lead frame. This makes it possible to maintain high positional accuracy between the light emitting element and the lead frame when manufacturing the integrated optical element having this configuration. In addition, since they are adhered by solder, the heat from the light emitting element can be efficiently dissipated as compared with the case where they are adhered by Ag paste.

According to the method of manufacturing an integrated optical element of the present invention, when manufacturing an integrated optical element in which at least a light emitting element is bonded directly or through a submount on a lead frame, a recess is formed in the lead frame, Solder is supplied to the concave portion of the lead frame, a light emitting element or a submount on which the light emitting element is mounted is placed on the solder, and bonding by solder is completed by heat treatment.

According to the method for manufacturing an integrated optical element of the present invention described above, a recess is formed in the lead frame, solder is supplied to the recess, and the light emitting element or the submount having the light emitting element mounted thereon is mounted thereon. By performing the heat treatment after mounting, the spread of the solder due to the heat treatment can be regulated by the recess formed in the lead frame, and the positional accuracy when the light emitting element or the submount is mounted can be maintained. . Further, since the bonding is performed by solder, the heat from the light emitting element can be efficiently radiated in the manufactured integrated optical element.

According to the method of manufacturing an integrated optical element of the present invention, a through hole is formed in a lead frame when manufacturing an integrated optical element in which at least a light emitting element is bonded to a lead frame directly or through a submount. The light emitting element or a submount on which the light emitting element is mounted is placed on a lead frame, solder is supplied to the through holes of the lead frame, and soldering is completed by heat treatment.

According to the method of manufacturing an integrated optical element of the present invention described above, the through hole is formed in the lead frame, the light emitting element or the submount on which the light emitting element is mounted is placed on the lead frame, and the through hole is soldered. By supplying the heat treatment and performing the heat treatment, the spread of the solder due to the heat treatment can be regulated by the through hole formed in the lead frame, and the positional accuracy when the light emitting element or the submount is mounted can be maintained. become. Further, since the bonding is performed by solder, the heat from the light emitting element can be efficiently radiated in the manufactured integrated optical element.

[0029]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention is an integrated optical element in which at least a light-emitting element is bonded directly or through a submount on a lead frame, and a recess is formed in the lead frame and embedded in this recess. It is an integrated optical element in which a light emitting element or a submount and a lead frame are bonded by soldering.

Further, according to the present invention, in the above integrated optical element, a metal is provided on a bonding surface of the light emitting element or the submount with the solder.

The present invention is an integrated optical element in which at least a light emitting element is adhered onto a lead frame directly or via a submount, and a through hole is formed in the lead frame, and the through hole is embedded in the through hole. It is an integrated optical element in which a light emitting element or a submount and a lead frame are bonded by soldering.

Further, according to the present invention, in the above integrated optical element, a metal is provided on a bonding surface of the light emitting element or the submount with the solder.

The present invention is a method for manufacturing an integrated optical element in which at least a light emitting element is bonded directly or via a submount on a lead frame, wherein a concave portion is formed in the lead frame, and the concave portion of the lead frame is formed. Is a method of manufacturing an integrated optical element, in which solder is supplied to the substrate, a light emitting element or a submount on which the light emitting element is mounted is placed on the solder, and adhesion by solder is completed by heat treatment.

Further, according to the present invention, in the method for manufacturing an integrated optical element described above, the solder is supplied so as to be contained in the recess.

Further, according to the present invention, in the method for manufacturing an integrated optical element described above, a metal is provided on a bonding surface of the light emitting element or the submount with the solder.

The present invention is a method for manufacturing an integrated optical element in which at least a light emitting element is bonded directly or through a submount on a lead frame, and a through hole is formed in the lead frame to form the light emitting element or the light emitting element. This is a method of manufacturing an integrated optical element in which a submount on which an element is mounted is placed on a lead frame, solder is supplied to a through hole of the lead frame, and bonding by solder is completed by heat treatment.

Further, according to the present invention, in the method for manufacturing an integrated optical element, the solder is supplied to the through hole from the side opposite to the light emitting element.

Further, in the present invention, in the method for manufacturing an integrated optical element described above, a metal is provided on a surface of the light emitting element or the submount that is bonded to the solder.

FIG. 1 shows a schematic configuration diagram (cross-sectional view) of an integrated optical element according to an embodiment of the present invention. As shown in Figure 1,
The sub-mount 13 having the light emitting element 14 mounted thereon is bonded onto the lead frame 11 to form the integrated optical element 10.

In the present embodiment, especially the lead frame 1
1 and the submount 13 are adhered to each other with solder 12, and a recess 11A is provided in a portion of the lead frame 11 that is in contact with the solder 12.

The base material of the lead frame 11 is F
e, Cu, etc. can be used. Fe has the advantage of low cost, and Cu has the advantage of high thermal conductivity.

The solder 12 for bonding the lead frame 11 and the submount 13 is made of, for example, Au, Sn, In, B.
A solder containing at least one metal selected from i can be used, and a conventionally known solder having another composition can be used.

With this structure, the recess 11A of the lead frame 11 blocks the spread of the solder 12 during heating. That is, the concave-convex portion 11A functions as a bank to prevent the solder 12 from spreading. Therefore, the solder 12
It is possible to prevent the positional deviation of the light emitting element 14 on the submount 13 due to the spread of the magnetic field, and to maintain the positional accuracy of the lead frame 11 and the light emitting element 14.

Since the solder 12 having a high thermal conductivity bonds the submount 13 on which the light emitting element 14 is mounted and the lead frame 11, the heat from the light emitting element 14 is applied to the lead frame 11 through the solder 12. It is released efficiently.

Further, in the present embodiment, the metal film 15 is formed on the lower surface of the submount 13, that is, the bonding surface with the solder 12. This metal film 15 is, for example, T
It can be formed by sequentially depositing i, Ni, and Au by, for example, a vapor deposition method.

The metal film 15 is provided to ensure wettability with the solder 12. The good wettability means that the solder 12 spreads over almost the entire surface of the metal film 15, whereby the lead frame 11
It is possible to widen the cross-sectional area of the surface on which heat is radiated to. That is, it means that the heat dissipation performance is improved. on the other hand,
The higher the wettability, the smaller the deformation of the solder 12 during melting, that is, the deformation due to the surface tension. Therefore, it is possible to reduce vertical displacement of the joining surface of the light emitting element 14 or the submount 13 in the vertical direction, and it is possible to reduce positional deviation such as lifting and to ensure positional accuracy.

The metal film 15 is preferably larger than the recess 11A of the lead frame 11 so that the metal film 15 covers the entire recess 11A. And the metal film 1
The larger the area of 5, the larger the area of contact with the solder 12, and the more the radiation performance can be improved.

However, if the metal film 15 is formed so as to cover the entire lower surface of the submount 13, the metal film 15 may be present when a large number of submounts 13 are produced by cutting from the wafer, for example. It becomes difficult to cut the wafer. Therefore, the metal film 15 is formed so as to be smaller than the lower surface of the submount 13 as shown in FIG. 1, or the metal film 15 is formed on the lower surface of the submount 13 after cutting the wafer (not shown). .

Here, the flow of heat (heat flow) from the light emitting element 14 in the integrated optical element 10 of FIG. 1 is schematically shown in FIG. As indicated by an arrow in the figure, a heat flow from the light emitting element 14 to the lead frame 11 through the submount 13, the metal film 15, and the solder 12 is generated. Submount 1
3 and the gap between the recess 11A of the lead frame 11 is solder 1
Since the area is filled with 2, the heat flow is secured with a cross-sectional area approximately equal to the size of the metal film (electrode) 15 provided on the bonding surface of the submount 13. That is, it can be seen that the decrease in the joint area between the lead frame 11 and the submount 13 due to the provision of the recess 11A is compensated by the solder 12.

Here, the thermal conductivity of the Ag paste is 3 W /
(M · K), thermal conductivity of tin solder is 49 W / (m · K)
(Toray Research Center; Latest trends in high-density packaging 99,
Chapter 3). Therefore, by using the solder 12 for adhesion as described above, the thermal conductivity is increased and the heat dissipation characteristics are improved. Furthermore, the final heat dissipation characteristic is determined by the thermal conductivity of each material in the heat dissipation path, the length of the path, and the cross-sectional area, that is, the thermal conductivity × the length of the path / cross-sectional area.

Of these, the cross-sectional area is substantially equal to the size of the electrode, that is, the metal film 15 formed on the bonding surface of the submount 13, and the length of the path is controlled by the supply amount of the solder 12. Therefore, by appropriately setting the supply amount of the solder 12, it becomes possible to fill the solder 12 without causing the submount 13 to float and without leaving a gap in the recess 11A of the lead frame 11.

Although not shown, the surface of the lead frame 11 is metallized with Au (gold) or the like, so that the wettability of the solder 12 can be improved and the occurrence of gaps can be suppressed, and at the same time, The floating of the submount 13 (lifting due to the surface tension of the solder 12) can be suppressed. For the same reason, it is preferable that at least the bonding surface side of the metal film 15 with the solder 12 is made of Au or Al.

The integrated optical element 10 shown in FIG. 1 can be manufactured, for example, as follows. First, as shown in FIGS. 3A and 3B, a lead frame 11 in which one concave portion 11A is formed in advance by pressing or the like is prepared.

Next, the lead frame 11 having the recess 11A is mounted on a holder (not shown). After that, as shown in FIG. 4A, the solder 12 is supplied to the concave portion 11A of the lead frame 11 using the alignment reference. At this time, in order to easily control the spread of the solder 12 in the subsequent heat treatment step, it is desirable that the solder 12 be supplied so as not to protrude from the recess 11A (in the horizontal direction) but to be housed in the recess 11A.

In the supply of the solder 12 and the alignment between the submount 13 and the lead frame 11 which will be described later, the alignment reference is provided separately on the outer end of the lead frame 11, the wall surface of the mold, or on the lead frame. Holes can be used. In the case where the lead frame 11 is provided with a hole, it is preferable that the hole is formed by pressing with a mold at the same time as the recess 11A, because the positional accuracy is improved.

At this time, as described above, the supply amount of the solder 12 is set to an appropriate amount. For example, sheet-shaped solder 12
In the case of supplying by the above method, it is possible to set the supply amount of the solder 12 and supply a constant amount of the solder 12 by managing the thickness and area of the sheet or the area and mass. For example, when the filamentous solder 12 is used for supply, it is possible to control the solder feed amount and the iron temperature.
For example, when the creamy solder 12 is supplied, it is possible to control the pressure and time of the dispenser, the needle diameter, and the viscosity of the creamy solder.

Subsequently, the light emitting element 14 and the submount 13 are aligned with the recess 11A of the lead frame 11 by using the same alignment reference as the above-described solder 12 supply process or a separately provided alignment reference. . At this time, the light emitting element 14 and the submount 15 are also previously
It is desirable to provide a marker that serves as a reference for alignment. Further, when the light emitting element 14 is mounted on the submount 13 in advance, it is preferable to perform alignment and adhesion of these. Then, as shown by the arrow in FIG. 4A,
The submount 13 on which the light emitting element 14 is mounted and the metal film 15 is formed on the lower surface is attached to the recess 11 of the lead frame 11.
The solder 12 in A is pressed and temporarily placed. This allows
As shown in FIG. 4B, the solder 12 and the metal film 15 are brought into contact with each other.

Next, a heat treatment process, that is, a so-called alloy process is performed. In this alloy process, the supplied solder 12 melts and spreads on the lead frame 11, but the recess 1
Since 1A is formed, the lead frame 1 is immediately formed.
It does not spread to the upper surface of 1. Then, when the solder 12 reaches the melting point, as shown in FIG. 4C, the solder 12 spreads throughout the recess 11A due to the wettability with respect to the surface of the lead frame 11, and the surface of the metal film 15 on the lower surface of the submount 13 also moves from inside to outside. It spreads toward. At this time, solder 1
If the supply amount of 2 is set appropriately, then the solder 12 spreads on the upper surface of the lead frame 11. Furthermore, solder 1
2 is the concave portion 11 of the lead frame 11 on the surface of the metal film 15.
It spreads out from A, enters the gap between the lead frame 11 and the metal film 15, and eventually reaches the metal film 1 as shown in FIG. 4D.
5 spreads over the entire surface.

Since the solder 12 spreads through such a process, the spread of the solder 12 is once stopped by the concave portion 11A, so that the positional deviation of the submount 13 due to the spread of the solder 12 in the alloying process can be reduced. . That is, the effective thickness of the solder 12 can be reduced.

In this alloying process, the members for which the temporary mounting process of the submount 13 has been completed may be processed individually or in a large number at once. Considering the efficiency of the alloy process, it is desirable to collectively process a large number of members that have undergone the temporary placement process.

When the members are individually processed in the alloying process, in order to more reliably prevent the submount 13 from floating, the side opposite to the bonding surface with the light emitting element 14 or the submount 13, that is, the submount 13 is prevented. It is also possible to apply a load by a method such as pushing with a collet from above, or to use a holding means such as chucking.

4A to 4D, the thickness direction is emphasized in order to make the behavior of the solder 12 easy to understand.

A plan view of the state of FIG. 4A is shown in FIG. 5A, and a plan view of the state of FIG. 4B is shown in FIG. 5B. As shown in FIG. 5A, the solder 12 is placed in the recess 11 of the lead frame 11.
Is supplied. Thereafter, the submount 13 is placed above the solder 12, and the submount 13 and the light emitting element 14 thereon are positioned as shown in FIG. 5B. still,
The plan view of the state of FIGS. 4C and 4D is the same as FIG. 5B.

1 to 5, the opening end of the recess 11A of the lead frame 11 is formed at a right angle. However, if the opening end is formed at an obtuse angle, press working becomes easier and the lead frame 11 is less likely to be deformed. Become.

When the integrated optical element in which the light emitting element 14 is arranged on the lead frame 11 is sealed,
Before or after the step of forming the recess 11A in the lead frame 11, for example, a process of pouring a mold of epoxy resin into a mold is possible.

According to the integrated optical element 10 of this embodiment described above, the recess 11A is formed in the lead frame 11, and the solder 12 embedded in the recess 11A mounts the submount 13 on which the light emitting element 14 is mounted. Is bonded to the lead frame 11. As a result, the solder 12
Has a better thermal conductivity than the Ag paste, it is possible to reduce the thermal resistance at the bonded portion. Therefore, when the integrated optical element 10 is used, the heat generated from the light emitting element 14 can be efficiently radiated to the lead frame 11 side through the submount 13 and the solder 12. In addition, when the integrated optical element 10 is manufactured, the spread of the solder 12 due to the heat treatment is prevented from occurring in the concave portion 11A
The position accuracy of the light emitting element 14 and the lead frame 11 can be maintained high.

In recent years, for example, in the case of performing high-speed writing on a DVD or a next-generation optical disc, a shorter wavelength 4
It is desired to use a light source in the 50 nm band, which increases the driving voltage of the semiconductor laser as shown in FIG.

According to the integrated optical element 10 of the present embodiment, the thermal resistance in the bonded portion can be reduced, so that the heat generated from the semiconductor laser having a high driving voltage can be efficiently dissipated. It will be possible. Also,
Since the positional accuracy between the light emitting element 14 and the lead frame 11 can be maintained high, it becomes possible to cope with the demand for higher accuracy due to the arrangement of each optical component due to the shorter wavelength of the light source. That is, it is possible to realize the integrated optical element 10 having the light emitting element 14 having a shorter wavelength.

Further, according to the integrated optical element 10 of the present embodiment, since the metal film 15 is provided on the adhesive surface of the submount 13, the wettability of the solder 12 with respect to the metal film 15 causes heat treatment. At this time, the solder 12 spreads on the surface of the metal film 15, and the submount 13 and the lead frame 1
The solder 12 can be inserted into the gap between the solder 12 and the solder 1.

Further, according to the present embodiment, the recess 11A is formed in the lead frame 11, and the recess 1 is formed.
Since it is sufficient to supply the solder 12 to 1A, as compared with the case where the solder bumps are formed on the submount and connected to the lead frame, the manufacturing cost can be reduced and the manufacturing cost can be suppressed with a simple process. .

In the present embodiment described above, one recess 11A is provided in the lead frame 11, but it is also possible to provide a plurality of recesses in the lead frame, and a recess not used for soldering is formed. You may. For example, as shown in FIG. 6A and FIG.
It is also possible to provide one rectangular recess 11B.
Incidentally, FIG. 6B shows a sectional view taken along line AA of FIG. 6A. In this way, the lead frame 11 has a plurality of recesses 11B.
By providing the lead frame 11 between them and leaving the lead frame 11 between them as a wall portion, the area ratio of the lead frame 11 on the bonding surface can be increased, and the lead frame 11 has a higher thermal conductivity than the solder 12, so that the heat dissipation can be improved. The efficiency can be further increased.

When forming a plurality of recesses in the lead frame in this way, from the viewpoint of workability of the lead frame, the positional accuracy of each recess, and the time required for the process, they are collectively pressed by the same die. Therefore, it is desirable to form a plurality of recesses.

Further, in the above-mentioned embodiment, the concave portion 11
Although A and 11B are rectangular, the shape of the recess formed in the lead frame in the present invention is not particularly limited.

Next, FIG. 7 shows a schematic configuration diagram (cross-sectional view) of another embodiment of the integrated optical element of the present invention. In the present embodiment, the lead frame is formed with a through hole.

As shown in FIG. 7, the submount 13 having the light emitting element 14 mounted thereon is soldered onto the lead frame 21 with solder 2.
The integrated optical element 20 is configured by being bonded by 2. In the present embodiment, a through hole 21A is provided especially in a portion of the lead frame 21 that contacts the solder 22. Further, similar to the previous embodiment, the metal film 15 is formed on the lower surface of the submount 13. The lead frame 2
The wall-shaped portion 21B that remains between the first through-holes 21A is connected to a portion outside the through-holes 21A, not shown.

Also in the present embodiment, it is preferable that the metal film 15 is made larger than the portion of the lead frame 21 where the through holes 21A are formed so that the metal film 15 covers all the through holes 21A. . Then, the metal film 15
The larger the area, the larger the contact area with the solder 22 and the better the radiation performance.

The integrated optical element 20 of the present embodiment uses a lead frame 21 having four through holes 21A as shown in FIGS. 8A to 8C, for example. 8B is shown in FIG. 8A.
It is sectional drawing in BB of. 8C is C- of FIG. 8A.
8 is a sectional view taken along line C, and the sectional view of FIG. 7 is similar to that of FIG. 8C. Four through holes 21A are formed around the cross-shaped portion 21B where the lead frame 21 remains. The cross-shaped portion 21B is wide and thin in the horizontal direction (longitudinal direction of the lead frame 21) in FIG. 8A, and narrow and thick in the vertical direction. Such a cross-shaped portion 21B uses both the process of forming a hole penetrating the lead frame 21 and the process of forming a recess up to the middle of the lead frame 21 in the thickness direction.
Alternatively, it can be formed by pressing using a mold corresponding to the shape of the through hole 21A.

As described above, by providing a plurality of, in this case, four through holes 21A in the lead frame 21, and leaving the lead frame 21 between them, the leads on the bonding surface can be compared with the case where there is only one through hole. The area ratio of the frame 21 can be increased. Since the lead frame 21 has a higher thermal conductivity than the solder 22, the heat dissipation efficiency can be further increased.

Since the other structure is the same as that of the previous embodiment, the same reference numerals are given and the duplicate description will be omitted.

The integrated optical element 20 of the present embodiment has such a structure that the through hole 21A of the lead frame 21 is formed.
As a result, the spread of the solder 22 during heating is blocked. That is, the through hole 21A serves as a bank to prevent the solder 22 from spreading. Therefore, the positional deviation of the light emitting element 14 on the submount 13 due to the spread of the solder 22 can be prevented, and the positional accuracy of the lead frame 21 and the light emitting element 14 can be maintained.

Since the solder 22 having high thermal conductivity bonds the submount 13 on which the light emitting element 14 is mounted and the lead frame 21, heat from the light emitting element 14 is applied to the lead frame 21 through the solder 22. It is released efficiently. Further, since the solder 22 has good wettability with respect to the metal film 15, the solder 22 can be spread on the surface of the metal film 15 to increase the contact area with the solder 22, and thus the heat from the light emitting element 14 can be further increased. One layer lead frame 21
The heat can be easily radiated to the side.

FIG. 9 schematically shows the flow of heat (heat flow) from the light emitting element 14 in the integrated optical element 20 of FIG. As indicated by an arrow in the figure, a heat flow from the light emitting element 14 to the lead frame 21 through the submount 13, the metal film 15, and the solder 22 is generated. Since the gaps between the submount 13 and the through holes 21A and the cross-shaped portions 21B of the lead frame 21 are filled with the solder 22, the size of the metal film (electrode) 15 provided on the adhesive surface of the submount 13 and Heat flow is ensured with approximately equal cross-sectional areas. That is, the decrease in the joint area between the lead frame 21 and the submount 13 due to the provision of the through hole 21A can be compensated by the solder 22.

Also in the integrated optical element 20 of the present embodiment, the length of the heat radiation path affecting the heat radiation characteristics is controlled by the supply amount of the solder 22, so by setting the supply amount of the solder 22 appropriately, It is possible to fill the sub-mount 13 with the solder 22 without causing the sub-mount 13 to float and without forming a gap in the through hole 21A of the lead frame 21.

Further, in the present embodiment, since the lead frame 21 is provided with the through hole 21A, the through hole 21A can be used as a marker (positioning reference) for the submount 13 and other parts arrangement. It is excellent in that it can Furthermore, since the opening of the through hole 21A is rectangular, it is possible to recognize X, Y, and
It can be used as a reference of θ. The through hole 21A
Even if is an opening shape other than a rectangular shape, it can be similarly used as a reference for X, Y, and θ by providing the opening with symmetry.

The integrated optical element 20 shown in FIG. 7 can be manufactured, for example, as follows. In the present embodiment, unlike the previous embodiments, the submount 13 is first
It is preferable that the solder 22 is supplied after the above components are temporarily placed on the lead frame 21. The manufacturing process can be the same as the manufacturing process of the previous embodiment shown in FIGS. 4 and 5, except that the order of the steps is changed. Hereinafter, steps different from the steps of manufacturing the integrated optical element 10 according to the previous embodiment will be mainly described. First, as shown in FIG. 10A, the four through holes 2 previously shown in FIGS. 8A to 8C are provided.
A lead frame 21 on which 1A is formed is prepared.

Next, the lead frame 21 having the through holes 21A formed therein is attached to a holder (not shown). afterwards,
As shown by the arrow in FIG. 10B, the light emitting element 14 and the submount 13 are aligned with the through holes 21A of the lead frame 21 by using, for example, four rectangular through holes 21A as alignment references. In the case of the present embodiment as well, it is preferable that when the light emitting element 14 is mounted on the submount 13, these elements are aligned and bonded in advance.

Then, as shown in FIG. 10C, the submount 13 on which the light emitting element 14 is mounted and the metal film 15 is formed on the lower surface is temporarily placed on the through hole 21 A of the lead frame 21.

In this temporary placing step, the submount 13 is transferred and landed on the lead frame 21 by suction using a collet, for example, and a load is applied using its own weight or a separately prepared weight. By doing so, the displacement of the submount 13 can be prevented.

Next, the submount 13 is attached by a collet or the like.
With the load applied to the lead frame 2
The solder 22 is supplied from the lower side of the first through hole 21A, that is, from the side opposite to the light emitting element 14 and the submount 13. Since the load is applied to the submount 13 in this way,
It is possible to prevent the displacement of the submount 13 in the solder 22 supply process.

The solder 22 includes thread-shaped solder, sheet-shaped solder, and cream-shaped solder as described above, but in the present embodiment, the cream-shaped solder 22 is convenient. In addition, as in the above-described embodiment, the solder 2
Set the supply amount of 2 appropriately.

Then, by performing an alloy process, the supplied solder 22 is melted and spreads on the lead frame 21, but since the through hole 21A is formed, the solder 22 immediately reaches the upper surface of the lead frame 21. Does not spread. When the solder 22 reaches the melting point,
The wettability with the surface spreads the entire inside of the through hole 21A, and the surface of the metal film 15 on the lower surface of the submount 13 also spreads from the inside to the outside. At this time, solder 2
If the supply amount of 2 is set appropriately, then the solder 22 spreads on the upper surface of the lead frame 11. Furthermore, solder 2
2 through the through hole 2 of the lead frame 21 on the surface of the metal film 15.
The lead frame 21 and the metal film 15 spread outward from 1A.
It penetrates into the gap between and and eventually spreads over the entire surface of the metal film 15.

Since the solder 22 spreads through such a process, the spread of the solder 22 is once stopped by the recess 11A, so that the positional deviation of the differential mount 13 due to the spread of the solder 22 in the alloying process can be reduced. Become.

Since the solder 22 spreads throughout the through hole 21A, airtightness is secured at the same time.
The deterioration of the sealing property due to the provision of 1A does not occur.

FIG. 11A is a plan view showing the state of FIG. 10A.
FIG. 11B is a plan view showing the state of FIG. 10B. As shown in FIG. 11A, four through holes 21A are formed in the lead frame 21. Then, as shown in FIG. 11B, the submount 13 and the light emitting element 14 thereon are positioned above the lead frame 21.
The plan views of the states of FIGS. 10C to 10E are the same as FIG. 11B.

According to the integrated optical element 20 of the present embodiment described above, the through hole 21A is formed in the lead frame 21,
With the solder 22 embedded in the through hole 21A,
Since the submount 13 on which the light emitting element 14 is mounted and the lead frame 21 are bonded to each other, the thermal resistance in the bonded portion can be reduced, so that the light source has a short wavelength and the driving voltage is high. It is possible to efficiently dissipate the heat generated from 14 to the lead frame 21 side. Further, when manufacturing the integrated optical element 20,
The spread of the solder 22 due to the heat treatment is
Since it can be regulated by the through hole 21A of No. 1 and the positional accuracy of the light emitting element 14 and the lead frame 21 can be maintained high, higher accuracy is required by the arrangement of each optical component by shortening the wavelength of the light source. It becomes possible to correspond to what is done. That is, according to the present embodiment as well, it is possible to realize the integrated optical element 20 having the light emitting element 14 having a shorter wavelength.

Further, according to the integrated optical element 20 of the present embodiment, since the metal film 15 is provided on the adhesive surface of the submount 13, the solder is provided in the gap between the submount 13 and the lead frame 21. 22 can be inserted.

According to the present embodiment, since the through hole 21A is formed in the lead frame 21 and the solder 22 is supplied to the recess 21A, the manufacturing cost can be increased by a simple process. It can be suppressed and manufactured at low cost.

Although four through holes 21A are formed in a rectangular shape in the present embodiment, the shape and number of the through holes formed in the lead frame in the present invention are not particularly limited.

FIG. 12 shows a schematic sectional view of one form of a composite integrated optical element as a functional element using the integrated optical element 21 of FIG. This embodiment shows a case where the present invention is applied to a composite integrated optical element used in an optical disc pickup. This composite integrated optical element 30 includes an integrated optical element 2 of FIG. 7 including a submount 13 on which a light emitting element 14 is mounted.
0, a mirror prism 31, a light receiving element (PDIC) 32,
A multi-lens 34 in which a plurality of lenses, a diffraction grating, and a HOE (holographic element) are integrated, and a composite prism 35 (3 formed by laminating a plurality of glasses or crystals
5A, 35B, 35C, 35D, 35E, 35F). The multi-lens 34 is generally produced by plastic molding, and is attached to the lead frame 21 by a molding material 33 shown in the drawing.

In this case, also for the light receiving element (PDIC) 32, by applying the method for manufacturing an integrated optical element according to the present invention, a through hole or a recess is formed in the lead frame 21 and the lead frame 21 is soldered to the lead frame 21. You may make it adhere | attach to.

In this composite integrated optical element 30, the laser light emitted from the light emitting element 14 is reflected by the mirror prism 31 and emitted upward, and is irradiated onto an irradiation target such as an optical recording medium. Further, the light reflected and returned by the irradiated body is reflected or separated at the interface of each prism of the composite prism 35, so that the light reception is detected at different positions of the light receiving element (PDIC) 32. Since the integrated optical element 20 according to the present invention is formed on the lead frame 21, the light emitting element 14 and the lead frame 21 of the integrated optical element 20 have high positional accuracy. 31, light receiving element (PDIC) 3
2, the light emitting element 14 can be arranged with high positional accuracy with respect to the multi-lens 34 and the compound prism 35.

In each of the above embodiments, the light emitting element 1
4 is bonded to the lead frames 11 and 21 by the solders 12 and 22 via the submount 13, but the light emitting element may be directly bonded to the lead frame by soldering depending on the chip configuration of the light emitting element. is there. In that case, the metal is provided on the lower surface of (the chip of) the light emitting element.

Further, in each of the above-described embodiments, the metal film 15 on the lower surface of the submount 13 has the entire recess 11A of the lead frame 11 or the through hole 21A of the lead frame 21.
Although it is configured to cover the whole, in the present invention,
The metal provided on the bonding surface of the light emitting element or the submount with the lead frame does not necessarily cover the entire recesses or through holes of the lead frame. It is also possible to form, for example, a recess or a through hole of the lead frame by forming a groove so that a part of the lead frame is protruded to the outside of the metal. It is also possible to improve it and to release excess solder to the outside. Further, regardless of the presence or absence of protrusion to the outside of such metal, if the total area of the metal provided on the bonding surface is made larger than the total area of the portion where the recessed portion or the through hole is formed in the lead frame, There is an effect that the heat radiation performance can be improved by making the contact area with the solder larger than the area of the portion where the recess or the through hole is formed.

Further, in each of the above-described embodiments, the metal film 15 is formed on the lower surface of the submount 13 by the vapor deposition method or the like, but it is also possible to attach a separately formed metal to the lower surface of the submount 13, for example. is there.

In each of the above embodiments, the solder 1
The heat treatment step of melting 2, 22 is described as an alloy step, that is, a step of performing overall heating by an alloy furnace. In the present invention, the heat treatment for melting the solder is not limited to the whole heating, and for example, a method of contacting a minute heater or irradiation of light (infrared light, ultraviolet light, visible light) from a lamp or a laser. Local heating such as a method utilizing light absorption may be used. Overall heating is easy to control temperature,
It has the advantage that the melting of the solder can be made uniform and uniform. Local heating has the advantage that heat-sensitive parts can be protected.

The present invention is not limited to the above-mentioned embodiments, and various other configurations can be adopted without departing from the gist of the present invention.

[0107]

According to the present invention described above, it is possible to reduce the heat resistance at the bonding portion with the lead frame and efficiently radiate the heat from the light emitting element to the lead frame side. Further, the recesses and the through holes formed in the lead frame can control the spread of the solder due to the heat treatment, so that high positional accuracy can be maintained between the light emitting element or submount and the lead frame. Then, since the recesses and the through holes are formed in the lead frame in advance and the soldering is performed, the integrated optical element can be manufactured by a simple manufacturing process.
It is possible to suppress an increase in manufacturing cost.

Therefore, according to the present invention, it is possible to construct a package at a low cost and to achieve high position accuracy and high heat dissipation efficiency at the same time while suppressing an increase in manufacturing cost by a simple process. In particular, due to the shorter wavelength of the light source of the light emitting element,
Although the amount of heat generated increases and the positional accuracy of each optical component becomes strict,
Since the present invention can deal with these, it is possible to realize an integrated optical element including a light emitting element having a light source with a shorter wavelength.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram (cross-sectional view) of an integrated optical element according to an embodiment of the present invention.

FIG. 2 is a diagram illustrating heat dissipation in the integrated optical element of FIG.

3A and 3B are diagrams showing a lead frame used in the integrated optical device of FIG.

4A to 4D are process drawings showing a manufacturing process of the integrated optical element of FIGS.

5A is a plan view in the state of FIG. 4A. FIG. B is a plan view in the state of FIG. 4B.

FIG. 6 is a diagram showing a case where a plurality of recesses are provided in the A and B lead frames.

FIG. 7 is a schematic configuration diagram (cross-sectional view) of an integrated optical element according to another embodiment of the present invention.

8A to 8C are views showing a lead frame used in the integrated optical device of FIGS.

9 is a diagram illustrating heat dissipation in the integrated optical element of FIG.

10A to 10E are process drawings showing a manufacturing process of the integrated optical element of FIGS.

11A is a plan view in the state of FIG. 10A. FIG. B is a plan view in the state of FIG. 10B.

12 is a schematic cross-sectional view showing one form of a composite integrated optical element configured by using the integrated optical element of FIG.

FIG. 13 is a diagram showing a state in which a submount having a light emitting element mounted thereon is bonded onto a conventional lead frame.

FIG. 14 is a diagram showing a force exerted on the submount by the Ag paste. B is a diagram showing a state in which heat from a light emitting element is dissipated.

FIG. 15 is a diagram showing a light output of an A light emitting device and a relationship between voltage and current. FIG. 3 is a diagram showing a relationship between a wavelength of a B light emitting element and a driving voltage.

[Explanation of symbols]

10, 20 Integrated optical element, 11, 21 Lead frame, 11A, 11B Recessed portion, 12, 22 Solder, 13
Submount, 14 Light emitting element, 21A Through hole

Claims (10)

[Claims] 1. An integrated optical element in which at least a light-emitting element is bonded directly or via a submount on a lead frame, wherein a recess is formed in the lead frame, and solder is embedded in the recess. An integrated optical element, wherein the light emitting element or the submount is adhered to the lead frame. 2. The integrated optical element according to claim 1, wherein a metal is provided on a surface of the light emitting element or the submount that is bonded to the solder. 3. An integrated optical element in which at least a light emitting element is adhered directly or through a submount on a lead frame, wherein a through hole is formed in the lead frame and embedded in the through hole. An integrated optical element, wherein the light emitting element or the submount is adhered to the lead frame with solder. 4. The integrated optical element according to claim 3, wherein a metal is provided on a bonding surface of the light emitting element or the submount with the solder. 5. A method for manufacturing an integrated optical element, which comprises at least a light-emitting element bonded directly or via a submount on a lead frame, wherein a recess is formed in the lead frame, and the recess of the lead frame is formed. A method of manufacturing an integrated optical element, comprising: supplying solder to a light emitting element, placing a light emitting element or a submount on which the light emitting element is mounted on the solder, and completing a bonding by the heat treatment. 6. The method for manufacturing an integrated optical element according to claim 5, wherein the solder is supplied so as to be contained in the recess. 7. The method for manufacturing an integrated optical element according to claim 5, wherein a metal is provided on a bonding surface of the light emitting element or the submount with the solder. 8. A method of manufacturing an integrated optical element, which comprises at least a light emitting element bonded directly or through a submount on a lead frame, wherein a through hole is formed in the lead frame, and the light emitting element or the light emitting element is formed. A method for manufacturing an integrated optical element, comprising: placing a submount on which is mounted on the lead frame, supplying solder to the through hole of the lead frame, and completing bonding by the solder by heat treatment. 9. The method of manufacturing an integrated optical element according to claim 8, wherein the solder is supplied to the through hole from the side opposite to the light emitting element. 10. The method for manufacturing an integrated optical element according to claim 8, wherein a metal is provided on a surface of the light emitting element or the submount that is bonded to the solder.