JPH0818003A - Solid-state relay - Google Patents

Abstract

PURPOSE:To provide a solid-state relay of low cost and high reliability wherein generated heat is kept law. CONSTITUTION:A photo-detection element 3 and source electrodes 11a and 11b of the first and second MOSFETs 5a and 5b are die-bonded an die pads 9c, 9a, and 9b, respectively. A cathode 3a of the photo-detection element 3 and repeating lead 10a are wire-bonded together with the use of a gold wire 8, and further, the repeating lead 10a and the source electrodes 11a and 11b of the first and second MOSFETS 5a and 5b are stitch-bonded with the use of a single aluminum wire 12. An anode 3b of the photo-detection element 3 and a repeating lead 10b are wire-bonded together with the use of a gold wire 8, and further, the repeating lead 10b and gate electrodes 13a and 13b of the first and second MOSFETs 5a and 5b are stitch-bonded with the use of an aluminum wire 12.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION This invention relates to solid state relays. Specifically, it relates to a solid state relay using MOSFET.

[0002]

2. Description of the Related Art In recent years, a solid state relay (hereinafter referred to as "SSR") using a MOSFET has been developed as a non-contact relay having a long life and suitable for high speed and high frequency switching. Two power MOSs as one of the SSRs
Some FETs (hereinafter referred to as "MOSFETs") are connected in anti-series between the source electrodes to accommodate both AC / DC output loads, and FIG. 9 shows the operating principle thereof. The light emitting element 52 converts an input signal input from the input terminals 60, 60 into an optical signal, and emits the optical signal toward the light receiving element 53. When the light receiving element 53 receives an optical signal, the light receiving element 53 converts the optical signal into an electric signal, and the gate electrode 56 of the first MOSFET 55a.
A negative voltage is applied to the gate electrode 56b of the second MOSFET 55b. Gate electrodes 56a, 56
When a negative voltage is applied to b, the first MOSFET 55a
A current path is opened between the source electrode 58a and the drain electrode 59a of the second MOSFET 55b and between the source electrode 58b and the drain electrode 59b of the second MOSFET 55b, so that the output terminals 61 and 61 are electrically connected.

However, when a positive load is applied to the drain electrode 59a of the first MOSFET 55a and the input terminals 60 and 60 are turned on, a negative voltage is applied to the first gate electrode 56a, One drain electrode 59
a → first source electrode 58a → second diode 57b
→ A current flows to the second drain electrode 59b, and the output terminals 61, 61 are turned on. In addition, with a positive load applied to the second drain electrode 59b, the input terminals 60, 6
When 0 is turned on, a negative voltage is applied to the second gate electrode 56b, and a current flows to the second drain electrode 59b → the second source electrode 58b → the first diode 57a → the first drain electrode 59a. Flows and the output terminals 61, 61 are turned on. Therefore, by electrically controlling ON-OFF between the input terminals 60, 60, ON-O is performed between the output terminals 61, 61 regardless of the load of AC / DC.
FF control is possible. Reference numeral 54 in the figure is a turn-off circuit, which is a circuit for shortening the turn-off time of the MOSFETs 55a and 55b.

FIG. 10 shows the conventional SSR5.
FIG. 1 is a plan view showing an example of No. 1 in which a light emitting element 52 and a light receiving element 53 are sealed with a transparent sealing resin 62 such as silicon gel in order to efficiently transmit an optical signal by reflecting it at an interface, Two MOSFETs 55a,
55b is integrally molded by molding with resin, and a pair of input terminal leads 63a, 63b and a pair of output terminal leads 64a, 64b are drawn out from the exterior resin portion 65. This SSR 51 is a lead frame 6
6, the lead frame 66 can be easily manufactured using the input terminal leads 63a,
63b, output terminal leads 64a and 64b, MOSFE
The die pads 67a, 67b, 67c for mounting the T55a, 55b and the light receiving element 53, and the pair of relay leads 68a, 68b are processed into a predetermined pattern.

To make the SSR 51, first, as shown in FIG. 11, a light emitting element 52 such as an LED is die-bonded to one of the input terminal leads 63a, and the light emitting element 52 is arranged in parallel with the light receiving element 53 such as a photodiode. Is die-bonded onto the die pad 67c. In addition, the die pad 67
The drain electrodes 59a and 59b of the MOSFETs 55a and 55b are die-bonded on the a and 67b, respectively. Next, the light emitting element 52 and the remaining input terminal lead 63b are connected to the gold wire 69.
After bonding with each other and bonding between each terminal of the light receiving element 53 and each of the relay leads 68a and 68b with a gold wire 69, the light emitting element 52 and the light receiving element 53 are sealed with a sealing resin 62. Also, the relay lead 68a and two MOSFEs
Aluminum wires 70 are bonded between the gate electrodes 56a and 56b of T55a and 55b, and aluminum wires 70 are bonded between the relay lead 68b and the source electrodes 58a and 58b. In this way, the light emitting element 52, the light receiving element 53, and the two MOSFETs 55a and 55b are mounted on the lead frame 66 so as to be substantially in a line, and finally, they are integrally sealed and molded to form the exterior resin portion 65. The SSR 51 can be manufactured separately from the lead frame 66.

[0006]

At this time, the relay leads 68a and 68b and the two MOSFETs 55a and 55b are provided.
As the aluminum wire 70 used for the wire bonding, a thick aluminum wire or a plurality of aluminum wires is used in order to minimize the wiring resistance.

However, the two MOSFETs 55
Since the source electrodes 58a and 58b of a and 55b and the relay lead 68b are wire-bonded by the aluminum wire 70, the electric resistance between the source electrode 58a and the source electrode 58b is two aluminum wires 70. And the electrical resistance of the relay lead 68b were considerably large. For example, the diameter is 200
When using the aluminum wire 70 of μm, 1 mm of aluminum wire
Since the relay lead 68b is made of copper, even if the resistance is ignored, if the length of the entire aluminum wire 70 between the source electrode 58a and the source electrode 58b is 20 mm, both The resistance value of the aluminum wire 70 between them is 12 mΩ. Therefore, if the source electrode 58 is
1.2W when 10A current flows between a and 58b
Therefore, it is necessary to take into consideration the heat dissipation from the SSR 51 and the operating conditions such as the ambient temperature. Further, the electric resistance between the gate electrodes 56a and 56b also becomes considerably large, resulting in an increase in the heat generation amount of the SSR 51 as a whole.

Further, a gold wire 69 is wire-bonded between each terminal of the light receiving element 53 and each of the relay leads 68a, 68b. Therefore, the relay leads 68a and 68b for wire-bonding the gold wire 69 are formed.
However, there is a problem in that the manufacturing process is complicated and the manufacturing cost is increased because it is necessary to perform plating such as gold plating having good bonding property with the gold wire 69.

Furthermore, two MOSFETs 55a, 55
b, the drain electrodes 59a and 59b are directly connected to the die pad 6
Since it is mounted by die-bonding on 7a and 67b, there is a risk of electric shock if the side surface of the die pad opposite to the output terminal leads 64a and 64b is exposed from the exterior resin portion 65. Therefore, the die pads 67a, 67b, 67 are prevented from exposing the side surfaces of the die pad to the outside.
c was in a state of being separated from the lead frame outer frame 66a (see FIG. 11). As a result, for example, when the MOSFET 55b is mounted on the die pad 67b,
As shown in FIG. 12A, the lead frame 66 is deformed by the weight and the die pad 67b is tilted,
It was difficult to perform wire bonding. In particular, it was more remarkable as the thickness was 0.5 mm or less and the lead frame 66 was thinner. Further, even if the deformation of the lead frame 66 is corrected and the die pad 67b is returned to the horizontal state and wire bonding is performed, the lead frame 66 is deformed again during the conveyance to the next step, and the die pad 67b is not formed as shown in FIG. 12B. Is sealed while being tilted, or the bonded aluminum wire 70 or gold wire 69 is cut,
There is also a problem that the yield of the SSR51 is deteriorated.

Further, the SSR 51 has a planar coupler structure in which the light emitting element 52 and the light receiving element 53 are arranged on the same plane, so that the light transmission efficiency is poor, and therefore a plurality of light emitting elements are emitted. The element 52 may be used to increase the amount of light emission. For example, like the SSR 71 shown in FIG. 13, another light emitting element 52 is mounted on the mounting lead 72, and the light emitting element 52 on the input terminal lead 63a and the mounting lead 72 are connected by the gold wire 69. I was bonding. At this time, as shown in FIG. 14A, a light emitting element 52 of the same type, for example, an N side-up type light emitting element 52.
By die-bonding the P side of the light emitting element 52 onto the input terminal lead 63a and the mounting lead 72, respectively, and the N side of the light emitting element 52 and the mounting lead 72 on the input terminal lead 63a with the gold wire 69. By bonding and bonding the N side of the light emitting element 52 on the mounting lead 72 and the remaining input terminal lead 63b with the gold wire 69, the two light emitting elements 52 are connected in series as shown in FIG. 14B. I was connected. Therefore, the mounting leads 72 for mounting the light emitting elements 52 must be plated with gold or the like, and each time the number of the light emitting elements 52 is increased, the number of mounting leads 72 to be plated is increased, which complicates the manufacturing process. And the cost was getting higher.

The present invention has been made in view of the drawbacks of the above conventional examples, and an object of the present invention is to suppress the amount of heat generation, reduce the manufacturing cost, and provide a solid state relay having high reliability. To provide.

[0012]

A solid state relay according to the present invention comprises a light emitting portion which switches between a light emitting state and a light extinguishing state, a light receiving portion which receives light emitted from the light emitting portion,
A first semiconductor switching element and a second semiconductor switching element that perform a switching operation by the photoelectromotive force generated in the light receiving section are provided, and the light receiving section, the first semiconductor switching element, and the second semiconductor switching element are provided. In a solid-state relay mounted on a lead frame almost in a row and sealed and molded, an electrode of the first semiconductor switching element and an electrode of the second semiconductor switching element electrically connected to an electrode of the light receiving section. Is characterized by direct wire bonding.

Further, it is preferable that the electrode of the light receiving portion and the electrode of the first semiconductor switching element are directly wire-bonded.

The light emitting portion includes at least one P side-up semiconductor light emitting element and at least one N side light emitting element.
A side-up semiconductor light-emitting device, and the P of the P-side-up semiconductor light-emitting device mounted on the lead portion
The N-side of the N-side up semiconductor element mounted on the side and other lead portions can be directly wire-bonded.

The lead frame is provided with an insulating lead supporting portion for supporting at least a lead portion for mounting the first semiconductor switching element and a lead portion for mounting the second semiconductor switching element. It may be that.

[0016]

According to the solid state relay of the present invention, the electrode of the first semiconductor switching element and the electrode of the second semiconductor switching element, which are electrically connected to the electrode of the light emitting portion, are directly wire-bonded. The wire length to be connected can be shortened as compared with the case where the electrodes of the light emitting portion and the electrodes of each semiconductor switching element are respectively bonded. Therefore, the wiring resistance of the wire is reduced and the heat generated by the wire can be suppressed. Also,
Since the number of bonding points is reduced, the connection failure at the bonding points is reduced, and the reliability of the solid state relay can be improved.

Further, by directly wire-bonding the electrode of the light emitting portion and the electrode of the first semiconductor switching element, the wire length can be further shortened and the wiring resistance and heat generation can be further reduced.

Further, since the P side of the P side-up semiconductor light emitting device mounted on the lead portion and the N side of the N side up semiconductor light emitting device mounted on another lead portion are directly wire-bonded, two or more. Even when the above light emitting element is used, it is not necessary to wire-bond the electrode of the light emitting element and the lead portion on which another light emitting element is mounted. Therefore, the number of bonding portions and lead portions to be plated is reduced, and the light emission amount can be increased at a low manufacturing cost.

Further, since the lead frame is provided with the insulative lead supporting portion for supporting the two lead portions on which the semiconductor switching element is mounted, the lead portion on which the semiconductor switching element is mounted is not bent and is horizontal to the lead frame. The wire for connecting the two semiconductor switching elements and the wire for connecting the light receiving portion and the semiconductor switching element can be sealed and molded without being cut. Of course, even if the lead support is exposed on the side surface of the solid-state relay, it is electrically insulating, so even if that part is touched, there is no electric shock. Also,
There is no possibility that a semiconductor switching element will be damaged due to surge current or the like.

[0020]

1 is a plan view showing a solid state relay 1 according to an embodiment of the present invention. Two
Is a light emitting element such as an LED, 3 is a light receiving element such as a photodiode, and 5a and 5b are output terminal leads 7a and 7 based on electric signals output from the light receiving element 3, respectively.
In the power MOSFET for ON-OFF control between b, the light emitting element 2 and the light receiving element 3 are covered with a transparent sealing resin 4 such as silicon gel.
The two MOSFETs 5a and 5b are integrally sealed and molded with a resin, and a pair of leads 6 for input terminals are used.
a, 6 b and the pair of output terminal leads 7 a, 7 b are drawn out from the exterior resin portion 14. The light emitting element 2 is die-bonded to one input terminal lead 6 a, and the upper surface electrode of the light emitting element 2 and the other input terminal lead 6 b are bonded with a gold wire 8. The light receiving element 3 is die-bonded on the die pad 9c, and the cathode 3a and the relay lead 10a of the light receiving element 3 and the anode 3b and the relay lead 10 are formed.
Each b is bonded by a gold wire 8. The relay lead 10a and the source electrode 1 of the first MOSFET 5a
The source electrodes 11b of the first MOSFET 5a and the second MOSFET 5b are bonded by one aluminum wire 12 (so-called stitch bonding). Of course, two aluminum wires 12 are used between the relay lead 10a and the source electrode 11a of the MOSFET 5a, and the source electrode 1 of the MOSFET 5a.
The 1a and the source electrode 11b of the MOSFET 5b may be bonded to each other. Similarly, the anode 3b of the light receiving element 3 also has the relay lead 10b, the gate electrode 13a of the first MOSFET 5a, and the second MOS.
The gate electrode 13a of the FET 5a is also bonded by the single aluminum wire 12.

In this SSR1, the first MOSF
Source electrode 11a of ET5a and second MOSFET 5b
Is directly wire-bonded to the source electrode 11b of the second electrode 5b, and the aluminum wire 12 to be used is different from the conventional case where wire bonding is performed between the relay lead 10a and the source electrode 11b of the second MOSFET 5b. Can be shortened, for example, the length can be reduced to about 1/3. Therefore, the wiring resistance of the aluminum wire 12 is reduced, and the amount of heat generated by the aluminum wire 12 can be reduced. Also MOSFET
In order to reduce the residual voltage (voltage drop that occurs when ON control is performed), even if a MOSFET with a small on-resistance is used, the conventional SSR51 generates a large amount of heat from the aluminum wire and uses a MOSFET with a small on-resistance. The effect was not obtained sufficiently. Therefore, shortening the aluminum wire 12 required for wiring as in the present invention is extremely effective for an SSR using a MOSFET having a small on-resistance.

Furthermore, in this SSR1, the number of bonding points is reduced, so that the manufacturing process can be simplified and the connection failure can be reduced to improve the reliability.

FIG. 2 is a plan structural view of an SSR 21 which is another embodiment of the present invention. In this SSR 21, two light emitting elements 2, an N side up light emitting element 2a and a P side up light emitting element 2b, are used in order to improve the transmission efficiency of the input signal. For example, as shown in FIG. 3A, the P side of the N side-up light emitting element 2a is die-bonded on the input terminal lead 6a, and the N side of the P side up light emitting element 2b is on the other input terminal lead 6b. The sides are die-bonded. In addition, the N side of the N side-up light emitting element 2a and the P side up light emitting element 2
The P side of b is bonded with a gold wire 8,
As shown in (b), the N side-up light emitting element 2a and the P side-up light emitting element 2b are connected in series. Thus, by wire bonding the N side of the N side-up light emitting element 2a and the P side of the P side up light emitting element 2b, the two light emitting elements 2a and 2b are connected in series without providing the mounting lead 72. be able to. Therefore, the plating process can be omitted and the manufacturing cost can be reduced. Further, since the number of bonding points is reduced, the light emission failure due to the connection failure is reduced, and the reliability can be further improved.

Further, in the second embodiment, the light receiving element 3
The cathode 3a and the source electrode 11a of the first MOSFET 5a are directly bonded by the gold wire 8, and the anode 3b of the light receiving element 3 and the gate electrode 13a of the first MOSFET 5a are also directly bonded by the gold wire 8. There is. In this way, if the light receiving element 3 and the first MOSFET 5a are directly wire-bonded without providing the relay leads 10a and 10b, the length of the aluminum wire 12 can be further shortened to reduce the amount of heat generation. Further, since the relay leads 10a and 10b are unnecessary, the manufacturing cost can be reduced and the SSR 21 can be downsized.

Even when three or more light emitting elements 2 are used, the N side up light emitting element 2a and the P side up light emitting element 2b are combined to form the N side up light emitting element 2.
The N side of a and the P side of the P side-up light emitting element 2b can be wire-bonded to connect the light emitting elements 2 in series. For example, when four light emitting elements 2 are used, as shown in FIG. 4A, the P side of the N side-up light emitting element 2a is die-bonded to one input terminal lead 6a, and the mounting lead 15 is attached. P side of the P side-up light emitting element 2b and P of the N side up light emitting element 2a
Die-bond each side. The N side of the P side-up light emitting element 2b is die-bonded to the remaining input terminal lead 6b. Then, the N side of the N side-up light emitting element 2a on the input terminal lead 6a and the P side of the P side up light emitting element 2b on the mounting lead 15 are bonded with a gold wire 8 to form the N side on the mounting lead 15. Up N-side of light emitting element 2a and input terminal lead 6b
The P side of the upper P side-up light emitting element 2b is connected to the gold wire
4 is bonded, the four light emitting elements 2a, 2b, 2a, 2b can be connected in series as shown in FIG. 4 (b).

FIGS. 5 (a) and 5 (b) are a plan structural view and a side structural view, respectively, of an SSR 31 which is still another embodiment of the present invention, which includes a die pad 9a having a first MOSFET 5a mounted thereon and a first pad 5a. The die pad 9b on which the second MOSFET 5b is mounted and the die pad 9c on which the light receiving element 3 is mounted are respectively supported by the lead supporting member 16. The SSR 31 can be easily manufactured by using the lead frame 17 shown in FIG. The lead frame 17 includes an input terminal lead 6
a, 6b, output terminal leads 7a, 7b, a die pad 9c for mounting the light receiving element 3, and MOSFETs 5a, 5b.
The die pads 9a and 9b for mounting the b are processed into a predetermined pattern. Also, three die pads 9
c, 9a, 9b and the lead frame outer frame 17a, the lower surfaces of the die pads 9c, 9a, 9b are supported by the lead frame outer frame 17a, and an insulating lead supporting member such as a polyimide film is used. 16 are provided. The light emitting elements 2a and 2b, the light receiving element 3 and the two MOSFs are provided at predetermined positions on the lead frame 17.
ET5a and 5b are mounted. Next, the light emitting elements 2a and 2b
After covering the light receiving element 3 and the light receiving element 3 with the sealing resin 4, as shown in FIG. 7, the light emitting element 2, the light receiving element 3 and the two MOSFs are provided.
The ETs 5a and 5b can be integrally sealed and molded, and finally the exterior resin portion 14 can be separated from the lead frame 17 to manufacture the SSR 31 shown in FIG.

In this way, the three die pads 9a, 9
b and 9c are supported on the lead frame outer frame 17a by the lead supporting member 16, so that the light receiving element 3 and the MOS
FETs 5a and 5b are connected to die pads 9c, 9a and 9 respectively.
die pads 9c, 9a, 9b even when mounted on
Does not tilt, and the light emitting element 2 and the MOSFETs 5a and 5b can be held horizontally with the lead frame 17. Therefore, the gold wire 8 and the aluminum wire 12 can be easily wire-bonded, the gold wire 8 and the aluminum wire 12 can be prevented from being broken, and the yield of the SSR 31 can be improved. Further, when the exterior resin portion 14 is separated from the lead frame 17, the cut end of the lead supporting member 16 is exposed on the side surface of the exterior resin portion 14, but since the lead supporting member 16 is insulative, the cut end is touched. However, there is no electric shock, and the MOSFETs 5a and 5b are not damaged by the surge current flowing from the cut end.

FIG. 8 is a side view of the structure of an SSR 41 according to still another embodiment of the present invention, in which the lead support member 16 is provided on almost the entire lower surface of the die pads 9a, 9b, 9c. Sealing molding is performed so that the lower surface of the support member 16 is exposed. If the lead support member 16 is made of a material having good thermal conductivity such as aluminum nitride (AlN) or silicon carbide (SiC), the lead support member 16 functions as a heat dissipation plate, and the MOSF
It is possible to efficiently dissipate the heat generated from the ETs 5a and 5b, and it is possible to provide a more reliable SSR 41.

[0029]

In the solid state relay of the present invention, the wire connecting the electrodes of the two semiconductor switching elements can be shortened, so that the wiring resistance and heat generation by the wire can be reduced.

Further, by directly wire-bonding the light receiving portion and the electrode of the first semiconductor switching element,
Since the wire connecting the light receiving portion and the semiconductor switching element is also shortened, it is possible to further reduce wiring resistance and heat generation by the wire, and it is possible to use in a wider range of conditions. Furthermore, since the number of bonding points is reduced, the reliability of the solid state relay can be further improved.

Further, the P side of the P side-up semiconductor light emitting element mounted on the lead portion and the N side of the N side up semiconductor light emitting element mounted on the other lead portion are directly wire-bonded to each other to form a bonding portion or a plating treatment. The number of lead portions to be reduced can be reduced, the manufacturing process can be simplified, and the manufacturing cost can be reduced.

Further, since the lead frame is provided with the insulative lead supporting portion for supporting the lead portions on which the two semiconductor switching elements are mounted, the lead portions on which the semiconductor switching elements are mounted are not bent and are horizontal to the lead frame. Therefore, disconnection of the wire between the semiconductor switching elements and the wire between the light receiving element and the semiconductor switching element can be prevented. Therefore, the yield of the solid state relay can be improved. Further, since the lead supporting portion is insulative, no electric shock is caused by the exposed lead supporting portion, and a surge current does not flow from the lead supporting portion to prevent damage to the semiconductor switching element.

[Brief description of drawings]

FIG. 1 is a plan structural view showing a solid state relay which is an embodiment of the present invention.

FIG. 2 is a plan view showing a solid state relay which is another embodiment of the present invention.

FIG. 3A is an enlarged explanatory view of the light emitting element mounting portion of the above,
(B) is an equivalent circuit diagram of the light emitting element mounting part.

FIG. 4A is an enlarged explanatory view of a light emitting element mounting portion of a solid state relay which is still another embodiment of the present invention;
(B) is an equivalent circuit diagram of the light emitting element mounting part.

FIG. 5A is a plan structural view of a solid state relay which is still another embodiment of the present invention, and FIG. 5B is a side sectional structural view thereof.

6 (a) and 6 (b) are explanatory views showing a part of the method for manufacturing the solid state relay of the same.

7 (a) and 7 (b) are continuation diagrams showing a method for manufacturing the solid-state relay of the same.

FIG. 8 is a side sectional structural view of a solid state relay which is still another embodiment of the present invention.

FIG. 9 is an explanatory diagram showing an operation of a conventional solid state relay.

FIG. 10 is a plan view showing a solid state relay of the above.

FIG. 11 is an explanatory view showing a method for manufacturing the solid state relay of the same.

12A and 12B are explanatory views showing problems in the solid-state manufacturing method of the above.

FIG. 13 is a partially cutaway plan view showing a solid state relay which is another conventional example.

FIG. 14A is an enlarged explanatory view of a light emitting element mounting portion of the solid state relay of the above, and FIG. 14B is an equivalent circuit diagram of the light emitting element mounting portion of the same.

[Explanation of symbols]

 5a, 5b MOSFET 3 light receiving element 3a light receiving element cathode 6a, 6b input terminal leads 9a, 9b, 9c die pad 11a, 11b source electrode 12 gold wire 16 lead support member

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Tada Yutaka Omron Co., Ltd. 10 Hanazono Dodocho, Ukyo-ku, Kyoto City, Kyoto Prefecture

Claims (4)

[Claims] 1. A light emitting unit that switches between a light emitting state and a light extinguishing state, and a light receiving unit that receives light emitted from the light emitting unit,
A first semiconductor switching element and a second semiconductor switching element that perform a switching operation by the photoelectromotive force generated in the light receiving section are provided, and the light receiving section, the first semiconductor switching element, and the second semiconductor switching element are provided. In a solid-state relay mounted on a lead frame in a line and sealed and molded, an electrode of the first semiconductor switching element and an electrode of the second semiconductor switching element electrically connected to an electrode of the light receiving unit. A solid-state relay characterized by direct wire bonding. 2. The solid state relay according to claim 1, wherein the electrode of the light receiving portion and the electrode of the first semiconductor switching element are directly wire-bonded. 3. The light emitting unit is composed of at least one P side-up semiconductor light emitting element and at least one N side up semiconductor light emitting element, and the P side up semiconductor light emitting element mounted on a lead portion. The solid state relay according to claim 1 or 2, wherein the P side and the N side of the N side-up semiconductor element mounted on the other lead portion are directly wire-bonded. 4. The lead frame is provided with an insulating lead supporting portion for supporting at least a lead portion for mounting the first semiconductor switching element and a lead portion for mounting the second semiconductor switching element. The solid state relay according to claim 1, 2 or 3, characterized in that.