JPH0870093A - Plastic molded type field effect transistor - Google Patents

Abstract

PURPOSE: To provide a plastic molded type field effect transistor at a low cost which can restrain switching noise without lowering the switching speed and is excellent in workability, productivity, etc. CONSTITUTION: The title plastic molded type field effect transistor is provided with a metallic substrate 2, an MOS-FET element 3, an outer lead 11 and a resin package 14. An EMI beads core 5 for protecting switching noise which core is connected in series between the gate electrode of the MOS-FET element 3 and the outer lead terminal 11 and sealed in the resin package 14 with resin is installed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resin-sealed field effect transistor (hereinafter referred to as a resin-sealed MOS-FET) used by incorporating it in a switching circuit.

[0002]

2. Description of the Related Art In recent years, resin-sealed MOS-FETs having excellent high frequency characteristics have been widely used as power switching elements. However, resin-sealed MOS-FET
The circuit incorporating the element as a switching element has a problem that when driven at a high frequency, noise (hereinafter referred to as switching noise) is generated due to the switching operation. Therefore, the following measures are taken to suppress this switching noise to a low level.
That is, a method of slowing the switching speed by increasing the resistance value of the gate resistance connected to the gate electrode of the resin-sealed MOS-FET, or the resin-sealed MO
E for switching noise prevention to the gate electrode, the drain electrode and the source electrode of the S-FET, or the external lead terminals connected to these electrodes via bonding wires.
This is a method of inserting an MI bead core (hereinafter referred to as EMI bead core). The latter method, which can suppress switching noise without slowing the switching speed, is widely used.

A conventional resin-sealed MOS-FET will be described below with reference to the drawings. FIG. 5 is a plan view showing a conventional resin-sealed MOS-FET. 1'is a conventional resin-sealed MOS-FET, 2'is a metallic substrate (not shown), a field effect transistor element (hereinafter referred to as MOS-FE).
A resin package in which (for example, T element) is resin-sealed,
3 ', 4', 5'are external lead terminals electrically connected to the respective electrodes of the MOS-FET element and exposed from the resin package 2 ', 6', 7 ', 8'are external lead terminals 3', EMI bead cores inserted into 4'and 5 '.

[0004]

However, in the above-mentioned conventional structure, it is difficult to insert the EMI bead core into the external lead terminal of the resin-sealed MOS-FET, and there is a problem that the workability is poor. Was there. Also, EMI
Since the bead core is made of a material having low toughness such as ferrite, it is necessary to perform reinforcement or the like in consideration of impact resistance and the like, and there is a problem that productivity is lacking. Furthermore,
When assembling the resin-sealed MOS-FET on a substrate,
The EMI bead core requires attention so that it will not come off from the external lead terminal, and there is a problem in that workability is also poor.

The present invention solves the above-mentioned problems of the prior art, and is capable of suppressing switching noise without delaying the switching speed, and is a low-cost resin-sealed MOS-type device which is excellent in workability and productivity. The purpose is to provide a FET.

[0006]

In order to achieve this object, a resin-sealed field effect transistor according to claim 1 of the present invention comprises a metallic substrate and a field effect grounded on the upper surface of the metallic substrate. A transistor element and an external lead terminal connected to a gate electrode, a drain electrode and a source electrode of the field effect transistor element via a bonding wire,
What is claimed is: 1. A resin-sealed field-effect transistor comprising: a metal substrate exposing one end of an external lead terminal; a field-effect transistor element; and a resin package for resin-sealing the external lead terminal. The EMI bead core for switching noise prevention, which is connected in series between the gate electrode, the drain electrode, the source electrode, and the external lead terminal, and is resin-sealed in a resin package. The resin-sealed field effect transistor according to claim 1, wherein the resin-sealed field effect transistor according to claim 1 is provided with an internal wiring substrate in which an EMI bead core for preventing switching noise is grounded on an insulating substrate. have.

Here, examples of the material used for the metallic substrate include Fe-Ni-Co alloys and copper alloys.
Examples of the material used for the bonding wire include gold, aluminum and copper. Examples of materials used for the external lead terminals include Fe-Ni-Co alloys and copper alloys. As a resin sealing method of the resin sealing type field effect transistor (resin sealing type MOS-FET), there are a transfer molding method (or transfer molding method), a casting method, an immersion method (or a deposition method), and a powder fluidized immersion. Law etc. are mentioned. When the resin-sealed MOS-FET is resin-sealed by the transfer molding method, the metallic substrate and the external lead terminals may be formed on the same lead frame. The lead frame may be formed of the same material as the electrode material of the MOS-FET element. As the resin material for resin sealing,
Depending on the resin sealing method, urethane, melamine, epoxy, silicone, unsaturated polyester, etc. may be mentioned. The EMI bead core for preventing switching noise is an electromagnetic interference (electromagnetic interference) such as switching noise generated in a circuit including a switching element or the like.
(Terence, EMI). Ferrite, amorphous, etc. are mentioned as an EMI bead core for switching noise prevention for this purpose. Examples of the material used for the insulating substrate of the internal wiring substrate include ceramics and aluminum. The internal wiring board is electrically connected to the switching noise prevention EMI bead core at both ends of the switching noise prevention EMI bead core grounded on the insulating board, and for connection with the bonding wire or the external lead terminal. It is preferable to provide a conductor because the EMI bead core for preventing switching noise can be easily connected to these bonding wires and external lead terminals, and the workability can be improved. One end of the conductor of the insulating substrate is grounded to the lower end surface of the EMI bead core for switching noise prevention, and the other end of the conductor is on one end surface of the insulating substrate on which the EMI bead core for switching noise prevention is arranged or one thereof. It may be exposed and formed on the other end surface excluding the end surface.

[0008]

With this configuration, since the EMI bead core is provided, the switching noise of the switching circuit can be suppressed without delaying the switching speed of the resin-sealed MOS-FET. Further, by sealing the EMI bead core together with the MOS-FET element and the like in a resin package, it is possible to prevent the EMI bead core from coming off from the external lead terminal. Further, the provision of the internal wiring substrate having the EMI bead core facilitates the wire bonding work in the wire bonding process and the like.

[0009]

【Example】

(Embodiment 1) A resin-sealed MOS-FET according to an embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows a resin-sealed MOS according to an embodiment of the present invention.
-A sectional side view showing the FET, Fig. 2 is a sectional plan view of Fig. 1,
FIG. 3 is a cross-sectional plan view of an essential part of FIG. 1 and 2, reference numeral 1 denotes a resin-sealed MOS according to an embodiment of the present invention.
-FET, 2 is a metallic substrate (or die pad) formed by laminating a plurality of drain electrodes, 3 is a MOS-FET element grounded on the metallic substrate 2, and 4 is an insulating substrate 4 described later.
a for internal wiring comprising a and conductors 15a to 15l,
5, 6 and 7 are switching noise preventing EMI bead cores (hereinafter referred to as EMI bead cores) grounded on the internal wiring substrate 4, and 8, 9 and 10 are gate electrodes, drain electrodes and source electrodes of the MOS-FET element 3. And bonding wires for electrically connecting the EMI bead cores 5, 6 and 7 to each other, 11, 12, 13 are external lead terminals electrically connected to the EMI bead cores 5, 6 and 7, 14
Exposes one end of the external lead terminals 11, 12, and 13 and exposes the metallic substrate 2, the MOS-FET element 3, the internal wiring substrate 4, the EMI bead cores 5, 6, 7 and the bonding wires 8, 9, 10 with resin. It is a resin package for sealing. In FIG. 3, 4a is an insulating substrate made of an insulating material such as ceramics, and 15a to 15l are conductors provided on the insulating substrate 4a.

A resin-sealed MOS having the above structure
Regarding the -FET, the manufacturing method thereof will be described below. First, a powder resin such as an epoxy resin is carried into a transfer pot. Next, the powder resin carried into the transfer pot is heated and melted. On the other hand, the insulating substrate 4
The conductors 15a to 15l are deposited on the upper surface of a to form the internal wiring substrate 4. Next, the EMI bead core 5 is adhered and formed over the conductors 15j and 15k of the internal wiring board 4. Next, in the same manner as described above, the conductors 15f to 15
The EMI bead core 6 is deposited over g and the EMI bead core 7 is deposited over the conductors 15b to 15c. Further, the MOS-FET element 3 is die-bonded to the upper surface of the die pad of the lead frame formed to have a predetermined shape. Next, the conductors 15l, 15 of the internal wiring substrate 4
External lead terminals 11, 12, and 13 are attached to h and 15d, respectively.
To solder. Next, the die pad (or drain electrode) of the lead frame, the gate electrode and the source electrode of the MOS-FET element 3, and the conductor 15 of the internal wiring substrate 4
Wire bonding of i, 15e, and 15a, respectively. Next, this assembly is set in a molding die.
Next, the casting resin is injected into the cavity of the molding die to form the resin package 14. Next, the resin-sealed MOS-FET 1 is taken out from the molding die and completed.

As described above, according to this embodiment, since the EMI bead core is provided, it is of course possible to suppress the switching noise of the switching circuit without delaying the switching speed of the resin-sealed MOS-FET.
Metallic substrate, MOS-F without exposing MI bead core
Since it is resin-sealed together with the ET element and the like, it is possible to prevent the EMI bead core from coming off the external lead terminal, and the EMI bead core from coming off the external lead terminal and being damaged by being dropped or the like. In addition, EM on the insulating substrate
Since it has an internal wiring board with the I bead core grounded,
In the wire bonding process and the like, the wire bonding work can be easily performed, and since the internal wiring substrate is provided with the conductor grounded to the EMI bead core, the bond point can be taken on this conductor, and the wire bonding work can be further performed. It can be done easily.

Next, an application example of one embodiment of the present invention will be described. FIG. 4 is a cross-sectional side view showing a substrate for internal wiring of a resin-sealed MOS-FET in an application example of one embodiment of the present invention. The difference from the embodiment of the present invention is that through holes 4b and 4b are formed in the internal wiring substrate 4, and conductors 15m and 15p are buried in the through holes 4b and 4b, respectively. Although not shown, conductors 15n, 15o and 15q, 15r for connecting the drain electrode and the source electrode of the MOS-FET element 3 to the external lead terminals 12, 13 are also embedded in the internal wiring substrate 4. There is. As described above, according to the application example of the embodiment of the present invention,
The external lead terminals and the EMI bead cores can be connected to the internal wiring board at the same time as the front and back surfaces of the internal wiring board.

[0013]

As described above, according to the resin-sealed field effect transistor of the present invention, the metallic substrate, the field effect transistor element grounded on the upper surface of the metallic substrate, and the field effect transistor element An external lead terminal connected to a gate electrode, a drain electrode, and a source electrode via a bonding wire, and one end of the external lead terminal is exposed to expose the metallic substrate, the field effect transistor element, and the external lead terminal with a resin. A resin package for sealing, which is a resin-sealed field effect transistor, comprising: the gate electrode of the field effect transistor element;
A switching noise prevention E, which is connected in series between the drain electrode and the source electrode and the external lead terminal and is resin-sealed in the resin package.
Equipped with MI bead core, resin-sealed MOS-FE
The switching noise can be suppressed without delaying the switching speed of T, and the impact from the outside of the EMI bead core can be buffered to prevent the EMI bead core from being damaged. Further, since the work of reinforcing the EMI bead core against impact resistance can be omitted and it can be prevented from coming off from the external lead terminal, the handling property at the time of assembling to the substrate or the like can be improved, and as a result, the assembling work or the like. And the switching circuit can be simplified. Therefore, it is possible to provide a low-cost resin-sealed field effect transistor having excellent workability, productivity, and reliability.

Further, the switching noise prevention EM
Since the I-bead core is provided with the insulating substrate grounded, the wire bonding work and the like can be easily performed, so that it is possible to provide a low-cost resin-sealed field effect transistor excellent in workability and productivity.

[Brief description of drawings]

FIG. 1 is a resin-sealed type MOS-in one embodiment of the present invention.
Cross-sectional side view showing FET

FIG. 2 is a sectional plan view of FIG.

FIG. 3 is a cross-sectional plan view of an essential part of FIG.

FIG. 4 is a sectional side view showing a substrate for internal wiring of a resin-sealed MOS-FET in an application example of an embodiment of the present invention.

FIG. 5 is a plan view showing a conventional resin-sealed MOS-FET.

[Explanation of symbols]

1, 1'resin-sealed MOS-FET 2 metallic substrate 3 MOS-FET element 4 substrate for internal wiring 4a insulating substrate 4b through hole 5, 6, 7, 6 ', 7', 8 'EMI bead core 8, 9,10 Bonding wire 11,12,13,3 ', 4', 5 'External lead terminal 14,2' Resin package 15a, 15b, 15c, 15d, 15e, 15f, 1
5g, 15h, 15i15j, 15k, 15l, 15
m, 15n, 15o, 15p, 15q, 15r conductor

Claims (2)

[Claims] 1. A metallic substrate, a field effect transistor device grounded on the upper surface of the metallic substrate, and an external device connected to a gate electrode, a drain electrode and a source electrode of the field effect transistor device through bonding wires. A resin-sealed field effect transistor comprising: a lead terminal; and a resin package that exposes one end of the external lead terminal to seal the metallic substrate, the field effect transistor element and the external lead terminal with a resin. An EMI for preventing switching noise, which is connected in series between the gate electrode, the drain electrode and the source electrode of the field effect transistor element and the external lead terminal and is resin-sealed in the resin package. A resin-sealed field-effect transistor having a bead core. 2. The resin-sealed field effect transistor according to claim 1, wherein the resin-sealed field effect transistor comprises an internal wiring substrate on which an EMI bead core for preventing switching noise is grounded on an insulating substrate. Static field effect transistor.