JPH0685126A - Semiconductor device - Google Patents

Abstract

PURPOSE:To provide a terminal assembly structure to obtain a reliable semiconductor device which is easy to assemble with respect to outgoing terminals and hardly influenced by external stress or thermal stress due to being subjected to heat cycles. CONSTITUTION:An outgoing terminal 6 is soldered to a ceramic substrate 2 mounted with semiconductor elements 4, and one end of the terminal is projected from the resin case 7. The case 7 is then filled with gelatinous resin 9, being sealed. The outgoing terminal 6 is integrated into the case 7 by insert molding. This facilitates the assembly of the semiconductor device including the outgoing terminal. In addition, external and thermal stresses exerted on the outgoing terminal are directly received by the case; therefore, unfavorable stress will not be applied to the ceramic substrate or the soldered part between the terminal and the substrate.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor device for a power transistor module used as a power switching element applied to an inverter or the like, and more particularly to an assembly structure thereof.

[0002]

2. Description of the Related Art First, a conventional assembly structure of a semiconductor device to which the present invention is applied is shown in FIG. In the figure,
1 is a metal base for heat dissipation, 2 is a ceramic substrate, 3 is a conductor pattern of the substrate 2, 4 is a semiconductor element (power transistor) mounted on the substrate, 5 is a bonding wire for internal wiring, and 6 is standing on the ceramic substrate 2. The external lead-out terminal soldered to the conductor pattern 3, 7 is an outer case made of a resin molded product, 8 is a similar resin molded product case lid, and 9 is a semiconductor device 4 sealed in the outer case. A gel-like resin such as a silicone gel filled in 10 is a molding resin such as epoxy that is injected and cured in the terminal lead-out portion of the outer case 7 to fix the external lead-out terminal 6.

With such a structure, the semiconductor element 4 is sealed and protected by the gel resin 9 in the outer case 7, and the external lead-out terminal 6 is fixed to the outer case 7 by the mold resin 10 so that the semiconductor substrate 4 and the ceramic substrate 2 are connected to each other. This prevents external stress and thermal stress due to heat cycles from being applied to the soldered parts in between.

[0004]

By the way, in the terminal assembly structure of the semiconductor device described above, in order to fix the external lead-out terminal 6 to the outer case 7, the external lead-out terminal 6 is assembled in a predetermined manner using an assembly jig. In addition to the need to accurately hold the position, the molding case 10 needs to be injected and cured around the external lead-out terminal 6 with respect to the outer case 7, resulting in a large number of assembly steps and a large number of parts. Assembling requires a lot of time and cost, resulting in an increase in cost. Also,
Since the mold resin 10 for fixing the external lead-out terminals 6 and the ceramic substrate 2 have large thermal expansion coefficients, the ceramic substrate 2 is cracked due to thermal stress due to the heat cycle, or the solder of the external lead-out terminals 6 is soldered. There is a problem that troubles such as deterioration of the attachment portion are likely to occur.

Further, when the semiconductor device is used as a switching element, high frequency noise is generated due to circuit inductance and stray capacitance based on current change (di / dt) and voltage change (dv / dt) accompanying switching operation. It is known that the noise is generated and propagates as inductive noise to the power supply circuit and the surrounding space to cause noise interference to peripheral devices. As a countermeasure, connect a noise cut filter to the circuit or ground the semiconductor device to ground. Conventionally, measures such as electrostatic shielding by accommodating it in a metal container have been taken. However, it is not preferable to attach a special metal container for electrostatic shielding because the weight increases and the size becomes large, and an improvement measure thereof is desired.

The present invention has been made in view of the above points, and a first object thereof is to solve the above-mentioned problems and to be excellent in assembling property, and to have a reliability that an external lead-out terminal is hardly affected by stress. An object of the present invention is to provide a high semiconductor device, especially a terminal assembly structure thereof. It is a second object of the present invention to provide a semiconductor device in which the package itself has an electrostatic shielding function so that the ambient propagation of induced noise generated by the switching operation of the power element can be favorably suppressed.

[0007]

The above first and second objects can be achieved by the present invention by configuring a semiconductor device as follows. First, for the first purpose, (1) the external lead-out terminal is insert-molded into a resin-made enclosure case to form an integral block.

(2) A pin block made of resin is integrally formed in the case penetrating portion of the external lead-out terminal, and a terminal lead-out hole corresponding to the outer shape of the pin block is opened on the side of the outer case, and the terminal lead-out hole is formed. The pin block is fitted into and bonded. (3) In the above item (2), the pin block is formed of an irregular contour body. (4) In the above item (1) or (2), a diverging leg portion is formed on the bottom side of the outer casing to join the substrate or the metal base.

(5) In the above item (1) or (2),
The outer case and the substrate or the metal base are alloy-bonded by soldering or the like. Further, there is the following configuration as a means for solving the second object. (6) The enclosure case is formed by mixing the casting resin with conductive powder. (7) A conductive film is formed on the inner peripheral surface of the outer case except the penetrating portion of the external lead terminal.

[0010]

With the constructions of the above (1) to (3), the external force applied to the external lead-out terminal during handling of the semiconductor device is directly received by the resin case, so that the external force is applied to the ceramic substrate or the soldering portion between the external substrate and the substrate. No stress acts.
In addition, by making the pin block a deformed contour body such as a gear shape, a cross shape, an ellipse shape, or a trapezoid shape, for example, the bonding area with the outer case becomes larger than that of a simple circular contour body,
As a result, a high adhesive force is obtained between the case and the case. Moreover, since the outer case is filled with the gel-like resin, there is almost no risk of applying thermal stress due to the heat cycle to the ceramic substrate and the soldered portion of the external lead terminal. Further, since the semiconductor device assembly line does not require the positioning and holding for fixing the external lead-out terminal, the injection of the molding resin, and the curing step, the number of assembling steps can be reduced.

Further, according to the construction of the above item (4), a wide bonding area is secured between the outer case and the other side ceramic substrate or the metal base. Further, in the configuration of the item (5), the outer case, the substrate, and the metal base are joined together as follows.
This can be performed at the same time in the same process as the soldering and joining of the substrate and the external lead-out terminal, and the number of steps for applying and curing the adhesive can be saved as compared with the fixing method using the adhesive.

On the other hand, according to the configurations of (6) and (7), the package of the semiconductor device itself has a function as an electrostatic shield, and the induced noise accompanying the switching operation of the power element is generated. It is possible to suppress noise interference that propagates to the peripheral space and affects peripheral devices.

[0013]

Embodiments of the present invention will be described below with reference to the drawings. In each embodiment, the same members corresponding to those in FIG. 7 are designated by the same reference numerals. FIG. 1 shows an embodiment corresponding to claim 1 of the present invention, in which an external lead-out terminal 6 is integrally molded by being inserted into a molding die of an outer case 7 made as a resin-molded product. The terminal 6 and the outer case 7 are integrally formed into a block. Then, when soldering the external lead-out terminals 6 to the ceramic substrate 2, the external lead-out terminals 6 are placed together with the outer case 7 at a fixed position on the ceramic substrate, and in this state, the resin case 7 is bonded and the external case Soldering between the lead-out terminal 6 and the conductor pattern 3 is performed. After that, the case lid 8 is adhered, and the inside of the resin case 7 is filled with the gel resin 9 to seal the semiconductor element 4.

FIGS. 2 and 3 show an embodiment corresponding to claims 2 and 3 of the present invention. In this embodiment,
First, with respect to the external lead-out terminal 6, a resin-made pin block 11 is integrally molded in advance at a portion where the terminal penetrates the resin case 7, and the terminal is embedded in the pin block. A terminal lead-out hole corresponding to the outer shape of the block 11 is opened. And
After the external lead-out terminal 6 is erected on the conductor pattern 3 of the ceramic substrate 2 and soldered, the outer case 7 is covered from above to fit the pin block 11 into the terminal lead-out hole on the case side, and between the both. Fix with adhesive.

In this case, as shown in FIGS. 3 (a) to 3 (c), the resin block 11 has the external gear shape, the cross shape,
By forming it as an irregular contour such as an ellipse, the adhesion area with the resin case will be larger than that of a simple circular contour, for example, so that a high adhesive force with the case can be obtained. The structure is even more robust. Figure 4
(A) and (b) respectively show an embodiment in which the structure corresponding to claims 4 and 5 of the present invention is applied to the outer case of FIG. That is, in FIG. 3A, the diverging leg portion 7a is formed on the bottom side of the outer casing 7 and is joined to the ceramic substrate 2 with an adhesive. By providing the diverging leg block 7a on the outer case 7 in this way,
A wider joint area can be secured and the package joint strength is increased. Further, in the figure (b), the bottom surface of the outer case 7 is metallized in advance, and the outer case 7 and the ceramic substrate 2 are alloy-bonded by soldering or the like without using an adhesive. , The solder joint is designated as 1
2 shows. According to this configuration, complicated steps such as application and curing of an adhesive are unnecessary, and the joining work between the outer case 7 and the ceramic substrate 2 is performed simultaneously with the soldering step of the external lead-out terminals 6. Therefore, there is an advantage that the number of assembling steps of the semiconductor device can be reduced. In addition,
The configuration shown in FIGS. 2A and 2B is the pin block 11 described in FIG.
It is needless to say that the same can be applied and applied to the enclosure case 7 adopting the above.

FIGS. 5 (a) and 5 (b) show an embodiment in which the outer case 7 in FIG. 2 is subjected to the measures against the induced noise according to claims 6 and 7 of the present invention. In this embodiment, the pin block 11 is formed as a cone with a trapezoidal cross section. First, (a) is an enclosure case 7,
An appropriate amount of carbon is added to the casting resin that is the material of the case lid 8.
Alternatively, the conductive powder 13 such as metal is dispersed and mixed, and the outer case 7 and the case lid 8 are molded. The pin block 11 does not contain conductive powder in order to secure the creeping insulation strength for the external lead-out terminal 6. Further, FIG. 7B shows that the inner case surfaces of the outer case 7 and the case lid 8 are removed except for the penetrating portion of the pin block 11 instead of mixing the conductive powder in the casting resin of the outer case 7 and the case lid 8. For example, a conductive thin film 14 of copper or lead alloy (film thickness 35
It is formed by printing or plating. The conductive thin film 14 can be directly grounded to the ground or can be grounded via the conductor pattern 3 of the ceramic substrate 2.

According to this structure, the package itself including the outer case 7 and the case lid 8 has a function as an electrostatic shield, so that the noise generated by the switching operation of the semiconductor element 4 incorporated in the case. Can be prevented from propagating to the surrounding space, and noise interference to peripheral devices can be prevented. The package structure of FIG. 5 can be applied to the outer case of FIG.

FIG. 6 shows an application example of each of the above-mentioned embodiments. That is, in each of the embodiments described with reference to FIGS. 1 to 5, the outer case 7 is joined to the ceramic substrate 2, whereas in this embodiment, the outer case 7 is joined to the metal base 1 to assemble the package. Has been done. In addition, the conductive thin film 14 described in FIG.
By applying the soldering joining method described with reference to FIG. 4B to the outer case 7 and the metal base 1 without depositing via the conductor package 3 of the ceramic substrate 2. Conductive thin film 1 that functions as an electrostatic shield
4 can be directly grounded to the ground side via the metal base 1.

[0019]

As described above, the semiconductor device of the present invention has the following effects. (1) By adopting the configurations of claims 1 to 3 of the present invention, a positioning jig is not particularly required to fix the external lead-out terminal to a fixed position, and the fixing with the outer case is easy. Therefore, the number of assembling steps is small. Moreover, since the outer case directly absorbs the external stress applied to the external lead-out terminal, the thermal stress due to the heat cycle, and the like, the solder joint between the external lead-out terminal and the substrate is not unduly applied with stress.

(2) According to the configuration of claim 4 of the present invention,
A wide bonding area can be secured for the outer case, and the bonding strength of the package is enhanced. (3) According to the structure of claim 5 of the present invention, the enclosing case and the substrate can be omitted by omitting the time-consuming steps of applying and curing the adhesive.
Alternatively, the joining work with the metal base can be simultaneously performed in the same step as the soldering of the external lead-out terminal and the substrate, and the number of assembling steps can be reduced.

(4) By adopting the constitutions of claims 6 and 7 of the present invention, it is possible to impart an electrostatic shielding function to the package of the semiconductor device itself, thereby providing a special electrostatic shielding container. However, the high-frequency noise generated by the switching operation of the power element can be effectively suppressed from propagating to the surrounding space and affecting other peripheral devices, but the function is excellent.

[Brief description of drawings]

FIG. 1 is an assembly configuration diagram of an embodiment corresponding to claim 1 of the present invention.

FIG. 2 is an assembly configuration diagram of an embodiment corresponding to claim 2 of the present invention.

FIG. 3 is a plan view showing a pin block outer shape contour body of an embodiment corresponding to claim 3 of the present invention, FIG.
(B) is a cross shape, (c) is an oval outline drawing

FIG. 4 shows an application example of FIG. 1, and (a) is an assembly configuration diagram of an embodiment corresponding to claim 4 of the present invention,
(B) is an assembly configuration diagram of an embodiment corresponding to claim 5 of the present invention.

FIG. 5 shows an application example of FIG. 2, wherein (a) is an assembly configuration diagram of an embodiment corresponding to claim 6 of the present invention,
(B) is an assembly configuration diagram of an embodiment corresponding to claim 7 of the present invention

6 is an assembly configuration diagram of an application example different from FIG.

FIG. 7 is an assembly configuration diagram of a conventional semiconductor device.

[Explanation of symbols]

 1 Metal Base 2 Ceramic Substrate 3 Conductor Pattern 4 Semiconductor Element 6 External Lead-out Terminal 7 Enclosure Case 7a Edge Spread Leg 8 Case Lid 9 Gel Resin 11 Pin Block 12 Solder Joint 13 Conductive Powder 14 Conductive Thin Film

Claims (7)

[Claims] 1. An outer casing made of resin is combined with an assembly in which a semiconductor element and an external lead terminal are mounted on a substrate laminated on a metal base for heat dissipation, and one end of the external lead terminal is separated from the outer casing. What is claimed is: 1. A semiconductor device in which an external lead-out terminal is insert-molded into a resin case to form an integrated block in a semiconductor device which is drawn out to the outside and is filled with a gel resin in an outer case and sealed. 2. An outer casing made of resin is combined with an assembly comprising a semiconductor element and an external lead terminal mounted on a substrate laminated on a metal base for heat dissipation, and one end of the external lead terminal is connected to the outer casing. In a semiconductor device in which the outer case is filled with a gel-like resin and sealed while being pulled out to the outside, a resin pin block is integrally formed at the case penetrating portion of the outer lead terminal, and A semiconductor device, wherein a terminal lead-out hole corresponding to the outer shape of a pin block is opened, and the pin block is fitted and adhered to the terminal lead-out hole. 3. A terminal assembly structure for a semiconductor device according to claim 2, wherein the pin block is formed of an irregular contour body. 4. The semiconductor device according to claim 1, wherein a diverging leg portion is formed on the bottom side of the outer case and is joined to a substrate or a metal base. 5. The semiconductor device according to claim 1, wherein the outer case and the substrate or the metal base are alloy-bonded by soldering or the like. 6. The semiconductor device according to claim 1, wherein the outer case is formed by mixing conductive powder such as carbon or metal in the casting resin. 7. The semiconductor device according to claim 1, wherein a conductive film is formed on the inner peripheral surface of the outer case except the penetrating portion of the external lead terminal.