JP2003332527A - Large semiconductor module - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To constitute a large semiconductor module of superior moisture resistance, large explosion-proof capability, high TCT reliability and of superior power cycle capability. <P>SOLUTION: This large semiconductor module comprises: a plate-like metal frame 51 provided with a plurality of openings; a semiconductor module 80 fitted to the opening of the metal frame 51; a plastic cover 54 covering one surface of the metal frame 51 to which the semiconductor module 80 is fitted; and a resin 59 with which the inside of the cover 54 is filled. <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 a large-sized semiconductor module constructed by assembling a plurality of IGBT semiconductor modules used as power devices for electric railways and vehicles.

[0002]

2. Description of the Related Art FIG. 5 is a sectional view showing an example of the internal structure of a conventional plastic module type IGBT module. A side wall 2 made of plastic is adhered to an end portion of the cooling metal plate 1, and an upper surface of the side wall 2 made of plastic is covered with a terminal cap 3 made of plastic. On the cooling metal plate 1, a copper plate 5 that is directly bonded or silver-bonded to the lower surface of the ceramic substrate 4 is soldered with solder 6. A copper plate 7 that forms a wiring pattern is attached to the upper surface of the ceramic substrate 4.
A semiconductor chip 8 such as an IGBT is soldered with a solder 13.

The semiconductor chip 8 is electrically connected to the wiring pattern of the copper plate 7 by wire bonding an aluminum wire 9. Further, on the wiring pattern of the copper plate 7, an emitter terminal 10, a collector terminal 11, and a gate terminal 12 made of copper are erected by soldering with solder 13, respectively, and the head is exposed to the outside of the terminal cap 3, and The terminal cap 3 supports these emitter terminal 10, collector terminal 11 and gate terminal 12. Further, in order to shield the semiconductor chip 8 from the outside air, a silicone resin 14 is filled inside, and an epoxy resin 15 is filled above the silicone resin 14.

[0004]

The conventional plastic module type IGBT module as described above has a structure in which the resin is sealed with the silicon resin 14 or the epoxy resin 15, but this resin sealing is Since it has a semi-hermetic structure, the conventional plastic module type IGBT module has a semi-hermetic structure.

Therefore, there is a problem that the moisture resistance is weak, and moisture enters the inside of the module in a high temperature and high humidity environment to cause deterioration of the characteristics of the semiconductor chip 8. Also,
Impurities (sodium, chrome, etc.) may be mixed in the silicon resin used for resin sealing, and there is a problem that the impurities may attack the semiconductor chip 8 and impair its reliability.

Further, since the outer member forming the module is made of plastic, the mechanical strength is weak, and there is a problem that there is almost no explosion-proof capacity when the semiconductor chip 8 explodes due to a short circuit accident or the like. Further, since the wiring patterns of the semiconductor chip 8 and the copper plate 7 are connected by aluminum wire bonding connection, the power cycle withstand capability is low (for example, only about 100,000 times with respect to the power cycle withstand requirement of about 1,000,000 times). ) Was a problem. Furthermore, there is a problem that the difference in thermal expansion between the cooling metal plate 1 and the ceramic 4 is large, and cracks due to the thermal stress generated thereby occur in the solder 6, impairing the TCT reliability of the module.

The present invention has been made in order to solve the above-mentioned conventional problems, and its purpose is to have high moisture resistance,
It is an object of the present invention to provide a large-sized semiconductor module configured by assembling semiconductor modules having a large explosion-proof resistance, a high TCT reliability, and an excellent power cycle durability.

[0008]

To achieve the above object, the present invention is characterized by a plate-shaped metal frame having a plurality of openings, a semiconductor module attached to the openings of the metal frame, and a semiconductor. It is provided with a plastic cover covering one surface of the metal frame to which the module is attached, and a resin filled in the cover.

According to a feature of the present invention, if a desired number of openings are provided in the metal frame, a desired number of semiconductor modules such as IGBTs can be attached to the metal frame, which facilitates various specifications of the user. Can respond.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a sectional view showing a semiconductor module used in a large-sized semiconductor module according to an embodiment of the present invention. A copper plate 3 is provided on the upper surface of the ceramic substrate 31.
3 is connected by silver brazing. Ceramic substrate 3
A circular low expansion metal flange 32 is provided on the outer side of the copper plate 1
Are connected by silver brazing.

A semiconductor chip 35 is soldered on the copper plate 33 with solder 34.

An emitter electrode member 36 made of molybdenum is pressed against the main surface of the semiconductor chip 35 by a spring 37, and the emitter electrode member 36 is pressed against the emitter electrode of the semiconductor chip 35 to form an emitter electrode path. The spring 37 is pressed from above by the ceramic housing 38 to generate a pressing force. A ring-shaped low expansion metal member 39 is brazed to the end of the ceramic housing 38 by silver brazing, and the upper portion of the ring-shaped member 39 is welded to the upper end of the flange 32.

Since the bottom surface, which is the collector of the semiconductor chip 35, is soldered to the copper plate 33, the copper plate 33 serves as the collector. A copper collector conductive member 40 is erected from the vicinity of the center of the copper plate 33 by soldering, which penetrates the emitter electrode member 36 and further penetrates the ceramic housing 38 to project to the outside.

Further, a copper emitter conductive member 41 is erected on the emitter electrode member 36, which penetrates the ceramic housing 38 and projects to the outside. The collector conductive member 40 is joined by caulking by a copper cap-shaped collector electrode 42 erected on the ceramic housing 38 by silver brazing, and the emitter conductive member 41 is made of copper erected on the ceramic housing 38 by silver brazing. The emitter electrodes 43 having a cap shape are joined by crimping. In this example, four semiconductor chips 35
Are housed in the semiconductor module described above.

According to the semiconductor module shown in FIG.
The circular upper and lower openings of the flange 32 made of low-expansion metal are hermetically closed by the ceramic substrate 31 and the ceramic housing 38 by silver brazing, welding or the like to form a closed container, and further on the ceramic housing 38. Since the through-holes of the protruding collector conductive member 40 and emitter conductive member 41 are hermetically closed by the cap-shaped collector electrode 42 and the cap-shaped emitter electrode 41 by silver brazing, the container has an extremely high airtightness (10 -9tor
r). As a result, the moisture resistance can be made extremely high, the intrusion of moisture or corrosive gas into the inside can be completely prevented, the failure of the semiconductor chip 35 can be prevented, and the reliability thereof can be remarkably enhanced.

Further, since metal and ceramic are welded and joined by silver brazing to form a closed container for the semiconductor chip 35, the mechanical strength is extremely larger than that of plastic or the like, and the semiconductor chip 35 explodes due to a short circuit or the like. Even so, it has a sufficient explosion-proof capacity, the sealed container is not destroyed, and the safety is improved.

Further, the semiconductor chip 35 does not use an aluminum wire or the like, but is pressed against the emitter electrode member 36 or the like,
Since it is connected to the emitter electrode 43 and the collector electrode 42 by soldering to the copper plate 33 and the electrode path is formed by a conductive member having a large current-carrying capacity, the power cycle resistance (1 million times or more) can be significantly improved. .

Further, since it is not necessary to use the cooling metal plate 1, even if the ceramic substrate 31 and the copper plate 33 have different thermal expansion coefficients, cracks do not occur and the TCT resistance can be improved. .

Further, since the dimensions of the module can be made the same as those of the conventional example, they can be used with the same dimensional specifications.

FIG. 2 is a sectional view showing another example of a semiconductor module used in the large-sized semiconductor module according to the embodiment of the present invention.

A cylindrical low expansion metal flange 32 is joined by silver brazing on a copper plate 33 which is joined by silver brazing on the top of the ceramic substrate 31. This copper plate 3
3, the bottom surface of the semiconductor chip 35 is soldered with the solder 34, and the bottom surface of the semiconductor chip 35 serves as a collector, so that the copper plate 33 is connected to the collector. Moreover,
Since the flange 32 made of low expansion metal is electrically coupled to the copper plate 33, the flange 32 also serves as a collector electrode.

Therefore, in this example, the ceramic housing 3
Only the cap-shaped emitter electrode 43, which is joined by caulking to the emitter electrode member 41 that is erected on the emitter electrode member 36, is erected on the upper part of FIG. 8 by silver brazing. Other configurations are the same as the example shown in FIG.

According to the semiconductor module shown in FIG. 2, since the flange 32 made of a low expansion metal is joined onto the copper plate 33 by silver brazing, thermal expansion of the copper plate 33 is suppressed, and as a result, FIG. TCT than the semiconductor module shown in
The withstand amount can be improved.

Further, since the flange 32 also serves as the collector electrode without impairing the power cycle resistance, it is not necessary to provide the collector electrode on the ceramic housing 38, and the device can be downsized and the assembly thereof. It is possible to improve the sex. Other configurations are similar to those of the semiconductor module shown in FIG. 1 and have similar effects.

FIG. 3 is a vertical sectional view showing an embodiment of a large-sized semiconductor module of the present invention. FIG. 4 is a cross-sectional view of the same large-sized semiconductor module. The screwing flange (metal frame) 51 forming the outer shell of the large semiconductor module has a quadrangular plane, and the small semiconductor module 8
It has a plurality of circular openings 52 for accommodating 0 (in this example, circular openings may be used). These openings 52
A circular small semiconductor module 80 is attached to this via a sealing rubber 53 by a screw (not shown). This small semiconductor module 80 is, for example, the one shown in FIG.

A plastic cover 54 is adhesively bonded to the upper portion of the screwing flange 51 to cover the small semiconductor module 80. The emitter electrodes 36 and collector electrodes 32 of these semiconductor modules 80 are made of conductive materials 55, 56.
Are connected in parallel with each other, and these conductive materials 55 and 56 are connected to an emitter electrode 57 and a collector electrode 58, which are arranged as electrodes of a large-sized semiconductor module on the plastic cover 54. Further, the inside of the plastic cover 54 is filled with a gel silicone resin 59 or an epoxy resin or the like for improving mechanical strength and insulation strength.

The lower portion of the large-sized semiconductor module as described above is used in close contact with a large-sized heat sink 60 by screwing (not shown) as shown in FIG.

According to the present embodiment, since a large number of semiconductor modules 80 (four in this example) capable of obtaining a desired capacity are attached to the screw flange 51, a large semiconductor module can be constructed. It is possible to quickly and easily meet the power specifications required by the user. Although the semiconductor modules 80 are electrically connected in parallel in the above-described embodiment, they may be connected in series. In this case, the withstand voltage module circuit specifications required by the user can be quickly and easily met. be able to.

[0029]

As described in detail above, according to the large-sized semiconductor module of the present invention, the power capacity of the semiconductor chip can be changed quickly and easily by adjusting the number of semiconductor chips mounted on the metal frame. It is possible to quickly and inexpensively respond to various specifications of the user.

[Brief description of drawings]

FIG. 1 is a sectional view showing an example of a semiconductor module used for a large-sized semiconductor module according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view showing another example of the semiconductor module used for the large-sized semiconductor module according to the embodiment of the invention.

FIG. 3 is a sectional view showing a large-sized semiconductor module according to an embodiment of the present invention.

4 is a cross-sectional view of the large-sized semiconductor module shown in FIG.

FIG. 5 is a cross-sectional view showing a configuration example of a conventional semiconductor module.

[Explanation of symbols]

31 Ceramic substrate 32 flange 33 Copper plate 34 Solder 35 Semiconductor chips 36 Emitter electrode member 37 spring 38 ceramic housing 39 Low expansion metal member 40 collector conductive member 41 emitter conductive member 42, 58 collector electrode 43,57 Emitter electrode 51 screwed flange 52 opening 53 Sea Link Barabers 54 cover 55, 56 Conductive material 59 Silicone resin 60 heat sink 80 Semiconductor Module

Claims (5)

[Claims] 1. A plate-shaped metal frame having a plurality of openings, a semiconductor module attached to the openings of the metal frame, and a plastic cover that covers one surface of the metal frame to which the semiconductor module is attached. A large semiconductor module comprising a cover and a resin filled in the cover. 2. The electrodes of the semiconductor module attached to the metal frame are connected in parallel or in series and connected to the electrodes protruding from the upper surface of the cover. Large semiconductor module. 3. The large-sized semiconductor module according to claim 1, wherein a surface of the metal frame to which the semiconductor module is attached, which is opposite to the surface covered with the cover, is attached to the heat sink. 4. The semiconductor module comprises a ceramic substrate having a metal plate bonded to the surface by brazing, and a cylinder hermetically bonded to the outer surface of the metal plate by brazing at an outer peripheral portion of the substrate. -Shaped metal flange, a ceramic disk-shaped hounding portion that hermetically closes the opening of the metal flange, and at least one semiconductor soldered to the metal plate on the surface of the ceramic substrate The large-sized semiconductor module according to claim 1, further comprising a chip. 5. The semiconductor module comprises a ceramic substrate having a surface to which a metal plate is joined by brazing, and a cylindrical shape in which an outer peripheral portion of the substrate is airtightly joined to the surface of the metal plate by brazing. A metal flange, a ceramic disk-shaped housing for hermetically closing an opening of the metal flange, and at least one semiconductor chip soldered to the metal plate on the surface of the ceramic substrate. The large-sized semiconductor module according to claim 1, further comprising: