JP2008270528A - Structure of semiconductor module - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a semiconductor module device having simple construction. <P>SOLUTION: In the structure of a semiconductor module 11 wherein the semiconductor module 11, consisting of a plurality of electrodes comprising a first type semiconductor 1 and a second type semiconductor 2, is fixed to a conductive casing, a grounding electrode 1E or a base plate 8 among the semiconductor module 11 is fixed directly to the casing. The casing serves as a heat radiating member 3 while the heat radiating member 3 is a metal containing aluminum or copper. In the case there is the grounding electrode N or a base plate 8 in a heat deteriorating member such as a smoothing capacitor or the like whose quality performance is deteriorated by heat except the semiconductor module 11, they are fixed directly to the heat radiating member 3. On the other hand, an inverter circuit is constituted by comprising a switching element Tr of semiconductor module. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a structure of a semiconductor module.

  Patent Document 1 below discloses a semiconductor module structure capable of realizing miniaturization of a module body as a semiconductor module and a semiconductor device. Specifically, in a semiconductor module and a semiconductor device, a plurality of semiconductor chips mounted on a supporting substrate are accommodated in one package, and at least a part of electrode terminals electrically connected to the semiconductor chip is provided. It has a structure that is exposed to the outside and an electrode is taken out from the semiconductor chip. In this semiconductor module and semiconductor device, the emitter electrode terminal is connected to the emitter electrode of the semiconductor chip on one end side, and exposed on the upper side of the module body on the other end side. The support substrate is made of a conductor, and the semiconductor chip itself is directly bonded on the upper surface side to be electrically connected to the semiconductor chip, while being exposed to the outside by forming the bottom surface of the main body on the lower surface side. It is a collector electrode terminal.

  The following Patent Document 2 discloses a method for mounting a non-insulated semiconductor power module that simplifies the mounting operation to the heat sink, and specifically, is as follows. First, an insulating sheet is attached to the upper surface of the heat sink. Next, a silicon-based adhesive having thermal conductivity and insulation is applied to the inner peripheral surface surrounded by the insulating sheet. The power module is placed on the adhesive and heated in an atmosphere of about 140 degrees to cure the adhesive. As a result, the power module (hereinafter also referred to as “semiconductor module”) and the heat sink (hereinafter also referred to as “heat radiating member”) are fixed with an adhesive in a state where a certain distance is maintained.

  Patent Document 3 listed below discloses a non-insulated semiconductor device that can easily fix an external electrode member to a base plate, and specifically, is as follows. When the external electrode member is fixed to the base plate, when a flat head screw is passed through the first through hole of the base plate from the back surface of the base plate, the head of the flat head screw is inserted into the truncated cone portion of the first through hole. Will fit. Further, after passing the tip of the countersunk screw through the second through hole of the external electrode member, the tip of the countersunk screw is tightened with a nut, thereby fixing the external electrode member to the surface of the base plate. At this time, the head of the countersunk screw is accommodated in a truncated cone-shaped portion formed in the lower portion of the first through hole of the base plate.

  Patent Document 4 listed below discloses a semiconductor device that can ensure insulation between a casing and a power module housed in the casing without hindering space saving and cost saving. Specifically, it is as follows. In the inverter case, the case is insulated from the IPM bus bar by an insulating member disposed between the bus bar of the intelligent power module (hereinafter also referred to as “IPM”) and the case adjacent thereto. A bracket provided to support the supported member is fixed to the case above the portion requiring insulation. And an insulating member is attached to the lower part of the bracket which is the existing components.

JP 2003-243611 A JP 2004-296976 A JP 2004-349486 A JP 2006-261385 A

  However, the techniques of Patent Literatures 1 to 4 leave room for improvement in the problem of a simpler structure. The present invention has been made in view of the above-described circumstances, and an object of the present invention is to realize a simple structure using only the minimum necessary components in a semiconductor module device. In particular, a simple semiconductor module by reducing the insulating material to the minimum necessary in an application product in which the ground terminal of the electrical circuit of the in-vehicle electrical component is incorporated in a car or the like that is negatively grounded to the chassis of the chassis (vehicle body metal part). It is possible to realize the structure of the semiconductor module, and to provide an optimum structure of the semiconductor module in terms of workability, quality, and cost. The purpose is to prevent the capacitor and the like from deteriorating and extend its life.

In order to achieve the above object, the structure of the semiconductor module according to the first invention employs the following first means.
That is, a structure of a semiconductor module for fixing a semiconductor module formed by joining a plurality of electrodes including a first type semiconductor and a second type semiconductor to a conductive housing, wherein a ground electrode or a base plate of the semiconductor module Use means to attach directly to the housing.

  According to the structure of the semiconductor module according to the first aspect of the present invention, it is possible to realize a simple structure using only the minimum necessary components since no insulating material is required. That is, among the plurality of electrodes constituting the semiconductor module, the same potential as the base plate and the casing to which the ground electrode is integrally joined is maintained, so that the corresponding terminals and insulating members can be omitted. In general, by not interposing an insulating material that is insulative with respect to heat, the thermal coupling between the semiconductor module and the heat dissipation member becomes higher. Therefore, as compared with a product having a conventional structure in which an insulating material is interposed between the semiconductor module and the heat radiating member, the cooling capability can be provided by a smaller heat radiating member if the output is the same and the heat generation amount is the same. For this reason, the products adopting the structure of the semiconductor module according to the first invention can be collected more compactly and can be reduced in cost.

  According to a second invention, in the structure of the semiconductor module according to the first invention, the casing also serves as a heat dissipation member, and the heat dissipation member employs a metal containing aluminum or copper. By adopting a metal containing aluminum or copper, which is a good conductor and having good thermal conductivity and workability, as a heat radiating member, a ground electrode or a base plate of a semiconductor module is directly attached to the heat radiating member and thermally coupled. It is possible to provide an optimum semiconductor module structure in terms of processability, quality, and cost to an automobile or the like whose electrical circuit is negatively grounded to the chassis.

  According to a third invention, in the structure of the semiconductor module according to the first or second invention, a ground electrode or a base plate of a thermally deteriorated component whose quality performance deteriorates due to heat other than the semiconductor module is directly connected to the heat radiating member. Adopting means for thermal bonding. This simplifies by omitting bulky insulating / heat-resistant components, etc., so that the efficiency of component placement is improved, and the entire apparatus can be reduced in size and weight and cost can be reduced.

  According to a fourth invention, in the structure of the semiconductor module according to any one of the first to third inventions, a configuration of an inverter circuit including a switch element by the semiconductor module is adopted. As a result, it is possible to provide a semiconductor module structure that is optimal for mounting a large-capacity inverter circuit equivalent to the driving force of an automobile or the like in an automobile or the like that is premised on mass production.

  According to a fifth invention, in the structure of the semiconductor module according to the third invention, the thermally deteriorated component is a capacitor. As a premise thereof, a smoothing capacitor that is generally important for a power conversion circuit such as an inverter circuit or a converter circuit is a large-capacity electrolytic capacitor.

  According to the structure of the semiconductor module according to the fifth aspect of the invention, when a product incorporating a smoothing capacitor is in use, a reactive current always flows through the corresponding electric circuit. Here, Joule heat is generated by the reactive current flowing in the resistance R component included in the smoothing capacitor. In order to prevent the electrolytic capacitor from deteriorating due to this heat generation, heat conduction is conducted to the heat radiating member directly attached from the ground electrode of the smoothing capacitor or the base plate to dissipate heat.

  For this reason, as compared with a product having a conventional structure in which an insulating material is interposed between the smoothing capacitor and the heat radiating member, the cooling capability can be provided by a smaller heat radiating member if the output is the same and the heat generation amount is the same. For this reason, the products adopting the structure of the semiconductor module according to the fifth invention can be collected more compactly and can be reduced in cost. Or it becomes possible to make a lifetime longer compared with the smoothing capacitor which does not employ | adopt a structure.

According to the present invention, it is possible to realize a simple semiconductor module structure by reducing the insulating material to the minimum necessary in an application product incorporated in an automobile or the like in which an electric circuit is negatively grounded in a housing chassis. . In addition, it is possible to provide an optimal semiconductor module structure in terms of processability, quality, and cost. Furthermore, it is possible to extend the life by preventing the deterioration of electrical components having properties determined by the operating temperature, such as electrolytic capacitors. In particular, the following points are effective.
1) It is no longer necessary to ensure insulation between the electrode or electric circuit and the casing of the inverter device, and the entire device is reduced in size, weight and simplification.
2) Since the ground terminal of the semiconductor module is eliminated, the semiconductor module is reduced in size.
3) Since electrical insulation between the semiconductor chip and the base plate is not required, the heat dissipation of the semiconductor chip is improved.
4) Since the ground potential is stabilized and the impedance between the inverter circuit and the ground is reduced, the electromagnetic shield (EMC) performance is improved.

  Hereinafter, an embodiment of the present invention (hereinafter referred to as “the present embodiment”) will be described with reference to the drawings. In addition, the same code | symbol is attached | subjected to the same function over each figure, and duplication of description is avoided.

  1A and 1B are explanatory views of the structure of the semiconductor module 11 according to the present embodiment, where FIG. 1A is a block diagram showing a main configuration, and FIG. 1B is a longitudinal sectional view of an applied product. As shown in FIG. 1A, the semiconductor module 11 is a kind of application product incorporated in an automobile or the like (not shown) in which an electric circuit is negatively grounded in a housing chassis, and illustrates an inverter power circuit. ing. This power circuit is an optimum application example of the semiconductor modules 11 and 12 (FIG. 2B) in this embodiment.

  As is well known, an electrical equipment such as an automobile is supplied with a substantially stable power by a battery 4 mounted on the vehicle. The battery 4 grounds the negative pole N to the heat dissipating member 3 and the housing chassis (hereinafter also referred to as “housing ground”), while the unipolar wiring (hereinafter referred to as “the ground”) connected to the positive pole P. Just called “plus wiring”), it can distribute power to almost all electrical equipment. That is, since the negative pole wiring (hereinafter also referred to as “minus wiring”) is substituted by the chassis, wiring from the battery 4 to the electrical equipment is unnecessary.

  1A, a semiconductor module 11 includes an NPN type power transistor Tr (hereinafter referred to as “switch”) in which a plurality of electrodes including a first type (N type) semiconductor 1 and a second type (P type) semiconductor 2 are joined. An inverter circuit (hereinafter also referred to as “three-phase inverter”) is configured by using 2 elements × 3 elements = 6 elements Tr ”or simply“ Tr ”. Specifically, two series Trs are connected from the plus pole P to the housing ground 3 (also used as a sign), that is, the plus side P collector is connected to the plus pole P, and the emitter is connected to the minus side Tr collector. 1E is connected to the housing ground 3 to constitute a switch element Tr for any one of the three-phase alternating currents of U, V, and W.

  It should be noted that only the grounded emitter is distinguished from others throughout all the drawings and is given the symbol of the emitter 1E, and has the same meaning as a ground electrode 1E or a base plate 8 described later. Further, regarding the first type (N type) semiconductor 1 and the second type (P type) semiconductor 2 described above, the first type semiconductor 1 is changed to P type and the second type semiconductor 2 is changed to N type by switching the N type and P type. In this case, a PNP type Tr is used. Further, the switch element is not limited to Tr, and any other power control element having a similar purpose, such as an FET or an SCR (thyristor) (not shown) may be used.

  A three-phase inverter is configured by connecting three U, V, and W circuits in parallel so that one phase is taken out from the connection point of the two series Trs. In addition, regarding the switch timing of the six Trs constituting the three-phase inverter, a three-phase AC switching pulse generated by a control circuit (not shown) is applied to the base of each Tr. Since it is a well-known technique as an inverter, further illustration will be omitted.

  As shown in FIG. 1B, the semiconductor module 11 has a control circuit with a certain spatial distance above the structure in which the emitter 1E or the base plate 8 is adhered and fixed to the heat radiating member 3 so as to be in close contact with each other. And a substrate 6 such as PPS (polyphenylene sulfide), which is a heat resistant resin having a temperature of 200 ° C. or more, and is covered with a heat resistant insulating cover 7.

  The heat radiating member 3 is made of a metal including aluminum or copper, which is a good conductor and has good thermal conductivity and workability. The ground electrode 1E or the base plate 8 of the semiconductor module 11 is directly attached to the heat radiating member 3 and heat is applied. Thus, the structure of the semiconductor module 11 that is optimal in terms of processability, quality, and cost can be provided to an automobile or the like whose electrical circuit is negatively grounded to the housing chassis 3.

  According to the structure of the semiconductor module 11, since the insulating material interposed between the ground electrode 1E or the base plate 8 and the heat radiating member 3 is not necessary, it is possible to realize a simple structure using only the minimum necessary components. . Moreover, generally, the thermal coupling between the semiconductor module 11 and the heat radiating member 3 becomes better by not interposing an insulating material having an insulating property against heat. Therefore, as compared with a product having a conventional structure in which an insulating material is interposed between the semiconductor module 11 and the heat radiating member 3, the cooling capability can be provided by the smaller heat radiating member 3 with the same output / the same calorific value. For this reason, the products adopting the structure of the semiconductor module 11 according to the present invention can be collected more compactly and can be reduced in cost.

  Further, by adopting the configuration of the inverter circuit including the switch element Tr having the structure of the semiconductor module 11 according to the present invention, a large-capacity inverter circuit equivalent to the degree of driving power of an automobile or the like is premised on mass production. It is possible to provide a structure of the semiconductor module 11 that is most suitable for being mounted on a certain automobile or the like.

  FIG. 2 is an electrical circuit of a product that adopts the structure of the semiconductor modules 11 and 12 according to the present embodiment. (A) The circuit diagram of the simplest inverter, (b) The circuit diagram of the inverter provided with the smoothing capacitor 5. is there. The semiconductor module 11 shown in FIG. 2A is as described along FIG. The semiconductor module 12 shown in FIG. 2B is configured such that the negative pole N of the smoothing capacitor 5 is directly attached to the heat radiating member 3 'as the ground electrode N or the base plate N (also used as a reference) and is thermally coupled. Has been.

  According to the structure of the semiconductor module 12, if a product incorporating the smoothing capacitor 5 is in use, a reactive current always flows through the corresponding electric circuit. Here, Joule heat is generated by the reactive current flowing through the resistance R component included in the smoothing capacitor 5. In order to prevent the electrolytic capacitor from deteriorating due to the heat generation, the heat is transferred by good heat conduction to the heat radiating member 3 'directly attached from the ground electrode N or the base plate N of the smoothing capacitor 5.

  For this reason, compared with a product having a conventional structure in which an insulating material (not shown) such as ceramic is interposed between the smoothing capacitor 5 and the heat radiating member 3 ', the same output / the same calorific value is smaller. Cooling capacity can be provided by the heat radiating member 3 '. Therefore, the products adopting the structure of the semiconductor module according to the present invention can be collected more compactly and can be reduced in cost. Alternatively, the lifetime can be made longer than that of the smoothing capacitor 5 that does not employ the structure according to the present invention. The heat radiating member 3 ′ may be an integral structure or a divided structure. However, from the viewpoint of extending the life of the smoothing capacitor 5, the heat dissipation member 3 ′ may have a structure that is less susceptible to heat generation from the semiconductor module 12 than the smoothing capacitor 5. preferable.

According to the present invention, a simple semiconductor module 11 can be obtained by reducing the insulating material to a necessary minimum in an application product in which an electric circuit is incorporated in a casing chassis 3, 3 '(also used as a sign) in a negatively grounded automobile or the like. , 12 can be realized. In addition, the structure of the semiconductor modules 11 and 12 that is optimal in terms of processability, quality, and cost can be provided. Furthermore, it is possible to extend the life by preventing the deterioration of electrical components having properties determined by the operating temperature, such as the electrolytic capacitor 5 (also used as a sign).
In particular, the following points are effective.
1) It is no longer necessary to ensure insulation between the electrode or electric circuit and the casing of the inverter device, and the entire device is reduced in size, weight and simplification.
2) Since the ground terminal of the semiconductor module is eliminated, the semiconductor module is reduced in size.
3) Since electrical insulation between the semiconductor chip and the base plate is not required, the heat dissipation of the semiconductor chip is improved.
4) Since the ground potential is stabilized and the impedance between the inverter circuit and the ground is reduced, the electromagnetic shield (EMC) performance is improved.

  The various shapes and combinations of the constituent members shown in the above-described embodiments are merely examples, and various modifications can be made based on design requirements and the like without departing from the gist of the present invention. For example, “semiconductor module”, “heat radiation member”, “ground electrode”, “base plate”, “switch element”, “inverter circuit”, or “power module”, “semiconductor device”, “intelligent power” according to the present invention. Regardless of the designation of “module”, “IPM”, etc., as shown in FIG. 1B, a semiconductor module in which the ground electrode 1E or the base plate 8 of the semiconductor module 11 is directly attached to the heat radiating member 3 and thermally coupled. Any structure may be used as long as the structure is 11. There is no strict definition of the base plates 8 and N, and in the present invention, the base plates 8 and N are used to mean conductive metal fittings for holding the semiconductor chip and other electronic components corresponding to the ground electrodes 1E and N.

  FIG. 1B is only a schematic explanatory diagram for exaggerating and explaining an example of the structure of the semiconductor module. Therefore, the peripheral structure of the semiconductor module 11 is not limited to the embodiment shown in FIG. That is, the presence or absence of the heat-resistant insulating cover 7 as an inverter case or the presence or absence of a bracket or a bus bar provided to support a supported member around a portion that requires insulation is also free. Furthermore, there is no distinction between the base plate 8 and the heat radiating member 3, and the ground electrode 1 </ b> E may be held by some conductive member and attached to the housing without an insulating member.

  And the electrolytic capacitor illustrated as a thermally deteriorated component said to this invention is only an example. That is, a heat-degraded component whose quality and performance deteriorates due to heat is used in addition to the semiconductor modules 11 and 12, and if the heat-degraded component has a ground electrode N or a base plate N, insulation / Since it can be simplified by omitting heat-resistant components, the efficiency of component placement is improved, and the entire apparatus can be reduced in size and weight and cost can be reduced.

  In short, the ground electrode 1E or the base plate 8 is directly attached to the heat radiating member 3 so as to reduce the number of insulating members to the minimum necessary to improve the thermal coupling, and the semiconductor modules 11 and 12 that are reduced in size and weight to the heat radiating member 3 are also provided. All techniques related to the structure are included in the present invention.

It is explanatory drawing of the structure of the semiconductor module which concerns on one Embodiment (this embodiment) of this invention, (a) The block diagram which shows a main structure, (b) The longitudinal cross-sectional view of an applied product. It is the electric circuit of the product which employ | adopted the structure of the semiconductor module which concerns on this embodiment, (a) The circuit diagram of the simplest inverter, (b) The circuit diagram of the inverter which attached the smoothing capacitor.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... 1st type semiconductor, 1E ... Ground electrode, 2 ... 2nd type semiconductor, 3, 3 '... Heat dissipation member,
5 ... Smoothing capacitor (electrolytic capacitor) 8 ... Base plate 11, 12 ... Semiconductor module,
Tr ... Switch element (transistor)
N ... Negative electrode (ground electrode or base plate)

Claims (5)

A semiconductor module structure for fixing a semiconductor module formed by joining a plurality of electrodes including a first type semiconductor and a second type semiconductor to a conductive casing,
A structure of a semiconductor module, wherein a ground electrode or a base plate of the semiconductor module is directly attached to the housing. The housing also serves as a heat dissipation member,
2. The structure of a semiconductor module according to claim 1, wherein the heat radiating member is a metal containing aluminum or copper.   3. The semiconductor module according to claim 1, wherein a ground electrode or a base plate of a thermally deteriorated component whose quality performance deteriorates due to heat other than the semiconductor module is directly attached to the heat radiating member and thermally coupled. 4. Structure.   The structure of the semiconductor module according to any one of claims 1 to 3, wherein an inverter circuit is configured including a switch element by the semiconductor module.   The semiconductor module structure according to claim 3, wherein the thermally deteriorated component is a capacitor.

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