JPS59201457A - Semiconductor device - Google Patents

Abstract

PURPOSE:To obtain a semiconductor device which is small in size and light in weight and has excellent heat dissipating efficiency by a method wherein the 1st conductive pattern is formed on a metal substrate, which is to be a heat dissipating substrate, with a flame spraied insulating layer in between and the 2nd conductive pattern is formed directly on the metal substrate and semiconductor elements are fixed on the two patterns and covered with a sealing cover and prescribed electrodes are protruded from the cover and those parts are molded with plastic. CONSTITUTION:The 1st conductive pattern 27 is formed on a metal substrate 31, which is to be a heat dissipating substrate, with a flame spraied insulating layer 29 in between and the 2nd conductive pattern 28 is formed directly on the substrate 31. Then diodes 4a and 4b are fitted on these patterns 27 and 28 respectively and they are enclosed air-tightly by a cover 38. After that an input electrode 23b, which connects the diodes 4a and 4b, and a rod electrode 25', which is connected to the pattern 27, are drawn out, piercing through the cover 38. After the 2nd and the 1st flat board electrodes 42 and 40 are connected to the electrodes 23b and 25' respectively, these electrode parts are surrounded by a plastic molded part 39 using adhesive 44.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a semiconductor device that requires high heat dissipation efficiency, and particularly to a semiconductor rectifier.

[Technical background of the invention]

Generally, vehicles such as automobiles are equipped with a generator for charging a battery. This generator is generally for three-phase alternating current, and the output of the generator is full-wave rectified by a rectifier circuit.

In Fig. 1, the terminals of the coil 1.2.3 of the star ≠ 1 star connection constituting the three-phase alternating current machine are connected to the first and second diodes 4a, 4b, the third and 4 diodes 5g.

5b, the connection point 22.2 of each diode of the diode pair consisting of the fifth and sixth diodes 6a, 6b.
3.24 respectively.

And the first, third and fifth diodes 4a r
The cand sides of 5a + 6a are commonly connected, and this common connection point 25 is connected to the positive electrode side of the battery 7. In addition, second, fourth and sixth diodes 4b, 5b,
The anode side of 6b is also commonly connected, and this common connection point 26
is connected to the negative electrode side of the battery 7. Further, a smoothing capacitor 37 is connected between the common connection point 25 on the positive side and the common connection point 26 on the negative side. Note that the common connection point 24 of the fifth and sixth diodes 6a + 6b in the figure is drawn out to the outside as a stator terminal ST connected to a car's cocometer.

In this way, in a three-phase AC rectifier, the generator coil 1
．． 2.3 The alternating current voltage generated in each case is rectified by a rectifier circuit consisting of three pairs of diodes and a capacitor 37, and the battery 7 is charged.

FIG. 2 is a sectional view showing the schematic structure of the generator and rectifier circuit as described above. In the figure, 9 is a fan integrated with the rotor 1o of the generator, 1 indicates the stator, that is, the coils 1, 2, and 3 in Figure 1, and 12 is the generator case (housing) that supports these. be. 1 in Figure 1. Third. Fifth diode 4a,,
5a, the heat dissipation electrode plate 1 where the cand side of 6th is the positive side
3a, and a device commonly attached to the second. 4th. 6th
diodes 4b, 5b.

The anode side of 6b is a rectifier consisting of a device commonly attached to the heat dissipation electrode plate 13b trap on the negative side.
*The part shown at 16b shows the part where the diode is provided. The rectifying device 13 has a portion on the heat-radiating electrode plate 13b side fixed to the support of the case 12, and a portion on the heat-radiating electrode plate 13a side is fixed to the case 12 via an insulator 15. In addition, the three input terminals 17 a + 17 b r of the rectifier L
17c1''l: Corresponds to the connection points 22, 23, and 24 in FIG. 1, and coil wire 1' drawn out from the stator 1.

2', 3' and 7 are connected respectively.

For example, the rotor 1o is rotated by an external driving force via the fan belt 8, etc., and a three-phase current voltage is generated in the coil in the solid foot. When this voltage is full-wave rectified by the rectifier, the rectifier generates heat due to the forward voltage drop of the diode. A rectifying device using this heat generation.
In order to prevent the temperature of L3- from rising, the case 12 is provided with a ventilation hole, and the airflow generated by the fan 9 causes the rectifier 13 to
is now being cooled.

3 and 4 show the first to sixth diodes 4ar4b, 5a, and 5b in FIG. 1.

A second circuit that integrally incorporates a rectifier circuit consisting of 6a and 6b.
It is a top view of the rectifying device 213- shown in the figure, viewed from the upper surface side and the lower surface 111. 5 is a sectional view taken along line a-a' in FIGS. 3 and 4. In FIG. 4, 13a and 13b are heat dissipation electrode plates on the positive and negative electrode sides, respectively, and these two heat dissipation electrode plates 13a and 13b
Three concave portions 16a, 16b are provided in each of the three concave portions 16a, 16b of the positive electrode side heat dissipation electrode plate 13m. Third. Fifth diode (a.

5a and 6a are released by the cand side? It is arranged so as to be electrically connected to the IA drawer plate 13a. Similarly, the fifth concave portion 16b of the third Pj of the heat dissipation electrode plate 13b on the negative electrode side is
As shown in the figure, they are arranged in second and fourth positions.

Also, in Figures 3 and 5, 18? 'i Insulating member, the above diodes 4a, 5a, 6a l 4b
, 5b + 6b are arranged. Each of the above diodes 4a
+ 5 a r 6 a r 4 b r5b, 6b heat dissipation board 1,? The electrodes not connected to a and 13b are electrode pieces 4a', 5a', 6a', and 4b'.

It is pulled out from the above-mentioned insulating member 18 via 5b' and 6b'. And a pair of diodes 4&.

Three electrode lead-out plates 19, 20, 21 are provided on the insulating member 18 so that 4b, 5a, 5, b and 6a, 6b are connected in series, and the first electrode lead-out plate 19 The electrode pieces 4 a' and 4 b' are connected to the electrode pieces 4 a' and 4 b', and similarly, the electrode piece 5 is connected to the second electrode lead-out plate 20.
g' and 5b', and electrode pieces 6a' and 6b' are connected to the third electrode lead-out plate 2, respectively. Each of these electrode lead-out plates 19 and 20゜21 has an input terminal 22 corresponding to the connection point 23 and 23゜24 in Fig. 1, respectively.
a H23ar24a is provided, and each input terminal 22
&.

One end of each of the aforementioned coils l r 2 + 3 is connected to 23a and 24m. Reference numerals 25 and 26 denote output terminals from which the rectified output of the diode is taken out, which are respectively attached to the heat dissipating electrode plate 13L of the positive electrode 9111 and the heat dissipating electrode plate 13bVc of the negative electrode side, and are connected to the positive and negative electrode sides of the battery shown in FIG. be done.

[Problems with background technology]

The conventional semiconductor rectifier configured as described above has a structure in which it is cooled by the wind generated by the fan 9 shown in FIG. In this case, it is not possible to sufficiently limit the temperature rise of the rectifier. For this reason, it was necessary to make the surface area of the rectifier as wide as possible and to dispose the diodes in a dispersed manner. In addition, the surface shape of the rectifier is made wide in plan so that it can easily catch the wind from the ventilation holes provided in the generator case. Also, it was heavy at about 133g. Furthermore, when a copper material with good thermal conductivity is used to enhance the heat dissipation effect of the heat sink, the weight is further increased. Along with this, rectifier 1
The generator itself, in which B is installed in the case ( )/Using ) 12, also had to be thick in shape and weight.

In addition, in some cases, the diode chip area is widened to prevent local heat generation of the semiconductor element, but in this case, the coefficient of thermal expansion between the silicon chip and the heat sink made of iron or copper, etc. The difference causes distortion, which increases thermal fatigue at the bonding surface between the silicon tip and the metal electrode, making the chip more likely to crack and reducing reliability. Furthermore, the price increases as the chip area increases.

Further, in the above example, the positive electrode side heat dissipation electrode plate 13a is made of an insulator 15.
Therefore, the space occupied by the rectifier L within the generator increases. Moreover, the contact area between the generator case 12 and the rectifier ε13 is small, and in particular, the positive electrode side heat dissipation electrode plate 13h is in direct contact with the case 12 (V), so that the hot film pull-up negative electrode side heat dissipation electrode plate 13b is It needed to be wider. Due to the above-mentioned circumstances, in the conventional rectifier, it is difficult to increase the current capacity to 55 A or more due to the limit of cooling efficiency.

[Purpose of the invention]

This invention was made in view of the above points, and aims to provide all semiconductor devices such as small, lightweight, and highly effective heat dissipating devices without deteriorating the device's characteristics such as reliability. That is.

[Summary of the invention]

That is, in the first semiconductor device according to the present invention, a sprayed insulating layer is formed on one surface of the metal plate, and the first conductive JI'f7 no.4 turn provided on the sprayed insulating layer and the sprayed insulating layer are Using a heat dissipation substrate having a second conductive layer provided in a portion where it is not formed, a semiconductor element such as a die-made semiconductor element is disposed on each of the first and second conductive layer patterns of this heat dissipation substrate. Furthermore, a sealing force/group for sealing this semiconductor element in a dry atmosphere is attached to the heat dissipation substrate/board and electrically connected to a predetermined portion of the semiconductor ζ element. It is equipped with a terminal electrode that is drawn out to the outside. For example, in a rectifier for automobiles, the first
The cathode side of the diode, which has a common cathode, is attached on the conductive layer pattern of the heat sink, and the anode side of the diode, which has a common anode, is attached on the second conductive layer pattern of the heat dissipation substrate, and the cathode and An input terminal and an output terminal that are electrically connected to the anode are attached, and a sealing cover that is integrated with the heat dissipation board and hermetically seals the diode in a dry shivering atmosphere is provided.

[Embodiments of the invention]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention, for example, a rectifier for an automobile, will be described below with reference to the drawings.

As shown in FIG. 6, the surface of a substrate 31 made of aluminum and having a thickness of, for example, 1.5 fi is roughened by, for example, sandblasting. Since this sandblasting treatment greatly influences the adhesion strength of the layer that will be thermally sprayed afterwards, the conditions must be carefully set, and here the surface roughness is set to 1.0-20 μm.

Next, a thermal spray insulating layer 29 having a thickness of 50 to 150 .mu.m is formed on the roughened surface of the substrate 31 by selectively plasma spraying a ceramic material such as At2O (alumina).

Next, copper is selectively sprayed onto the surfaces of the insulating layer 29 and the substrate 31 to form the first to third sprayed metal layers 27°2B and 27JO having a thickness of 50 to 150 μm, thereby forming a heat dissipating substrate unit that also serves as an electrode. get. Here, the first metal layer 27 is entirely sprayed on the insulating layer 29, and the second sprayed metal layer 28 and the third sprayed metal layer 30 are sprayed on the substrate 3. The spraying method for the sprayed metal layer 27°28.30 is plasma spraying.

There are arc spraying, flame spraying, etc.

After forming the heat dissipation board 43f as described above, a first sprayed metal layer 27 is formed on the heat dissipation board 43f. Third.
Fifth diode 4a, 5a.

The cathode side of the electrode 6a and a part of the rod-shaped electrode 25' are fixed by brazing. Similarly, a second sprayed metal layer 28 is formed on the second sprayed metal layer 28. 4th. Sixth diode 4b.

The anode sides of 5b and 6b are fixed by brazing. A capacitor ground terminal 26 is fixed by brazing onto the twisted third thermally sprayed insulating layer 30. In addition, the anode of the adjacent first diode 4a and the second diode 4
The cathode b is fixed to the horizontal portion of the L-shaped first human-powered electrode 22b by brazing. Similarly, the anode of the third diode 5a and the cathode of the fourth diode 5b are connected by the L-shaped second manual electrode 23b, and the anode of the fifth diode 6a and the cathode of the sixth diode 6b are connected. The third human power electrode 24b7il is connected to form a three-phase alternating current rectifier circuit. In addition, the third human power electrode 24
The protruding portion ST' of b is a stator terminal electrode.

Next, as shown in Figure 887, the rod-shaped electrode 25 and the first to third human-powered electrodes 22b, 23b, 24b.

In order to protect the stator terminal electrode ST' and the capacitor ground terminal 26' from mechanical external force, a sealing cover 38 made of aluminum or synthetic resin is fixed to the heat dissipation board with a resin material or by heat pressure bonding. . At this time, four circular electrodes 25', input electrodes 22b,
23b, 24b.

Stator terminal electrode ST'%" and core tear VRVl"
A portion of the vertical portion of each land terminal 26 is covered with a cover 38.
It will be in a state where it has come out of. Furthermore, a ventilation hole is provided in this cutter 38 for the purpose of removing the air inside and enclosing a dry gloss atmosphere.
can be installed.

Subsequently, as shown in FIG. 8 and FIG. 9, which is a cross-sectional view taken along line a-a' in FIG. A plastic molded part 39 is placed on -38 and fixed with adhesive 44. Then, a rod-shaped electrode 25' and a stator terminal electrode ST' are attached to the first flat plate electrode 40 and the second flat plate electrode 41, respectively, which are attached to this plastic molded part 39.
to braze. In addition, pipe-shaped parts 36 on the way - Pika /
Insert and fix the 7-braided part 36 into the ventilation holes of the plastic molded part 39, the input electrodes 22b, 2Jb, 24b, the capacitor ground terminal 26', and the part from which the twig-shaped part 36 is drawn out. Pour the insulating resin part 42 into it! Make it II.

4) Although the heat dissipation board L'' has good thermal conductivity, the thermally sprayed insulating layer 29 is porous and has poor moisture resistance. After extracting the air from the hollow portion surrounded by and introducing dry nitrogen or dry air, the open end of the F-shaped part 36 is closed.

In the rectifier manufactured by pressurizing as described above, the input electrode 22b drawn out from the plasti-Kumold part 39,
23b and 24b are each three-phase AC input S': t4
The substrate 3 on the back side of the heat dissipation board becomes the negative output end of the arm flow output, and the first flat plate end pole 40 becomes the positive output end of the rectified flow output. In Figure 8, a smoothing capacitor corresponding to the capacitor 37 in Figure 1 is not shown.

FIGS. 10 and 11 are a sectional view and a partial plan view showing how the rectifying device is attached to the generator. In the figure, the heat dissipation board 43 on the back side of the flow rectifier according to the present invention is the negative electrode, that is, the ground't-? If the positive electrode is not set on the part, it is not exposed/exposed, as in the conventional case.
There is no need to float it on the case 12 via a T body, and it can be attached to the case 12 closely. Dimensions, input? fj, pole 22b.

A part of the vertical 1b of 23b and 24b is connected to the -V'itA fllll of Koilno and 2I3, respectively, and the 1st plate army 4 ('Jj41
') is connected to the positive terminal of the battery (V), not shown.

〔Effect of the invention〕

As described above, in the device 1B according to the VC of the present invention, the number of rotations of the fan 9 is low because the back surface of the heat dissipating base 4 made of aluminum or the like can be tightly fixed to the case 12 of the IR rock. Even if the membrane flow device aU, this equipment! The heat from the air is directly transferred to the case 12 of the machine, and the case 12 is further cooled by the wind generated by the fans 9 (1) and (II+), so that the case 12 is efficiently cooled. According to this embodiment.

A semiconductor device with a thermal resistance of 64°C/W and a rectified output of 65A when stacked in a generator is 1. Attachment u'1. The diodes 4a, a, 6a and the first part of the die 4b can be realized.
It was confirmed that the temperature difference between 5b and 6b could be reduced to 5°C or less.

Furthermore, since the rectifier has good heat dissipation characteristics when attached to the generator, there is no need to increase the size of the rectifier itself, and as shown in FIGS. We were able to significantly reduce the installation area. For example, with conventional equipment, the installation area to the generator was about 50 cm2, but it has been reduced to about 24 crn2, and the weight is 13 cm2.
From about 3g to 44. ! It has become possible to make the il smaller and lighter. Accordingly, the generator case 12 can be made smaller and lighter.

In addition, by sealing the diodes 4a, 5a, and 6a on the thermally sprayed insulating layer 29 of the heat dissipation board-L in a dry atmosphere, deterioration of withstand voltage due to moisture absorption, which is a drawback of the thermally sprayed insulating layer 29, is prevented and reliability is improved. I was able to increase it.

Incidentally, although the above embodiment has been described in the case of an automatic military rectifier, the present invention is not limited to the above embodiment. For devices where heat generation from the semiconductor element is a problem, a 7'0 heat dissipating substrate is used as part of the package that hermetically seals the semiconductor element, and a thermally sprayed 4φ diaphragm is formed on this substrate via an appropriate thermally sprayed insulating layer. Mount the semiconductor device on the glue,
If an input/output device is provided outside the package and the semiconductor element is hermetically sealed in a dry atmosphere, 1? This is effective because the highly thermally conductive heat dissipating substrate that is part of the package acts as a heat dissipator.

Further, in the above embodiment, the heat dissipation board was used as the negative output terminal, but the semiconductor element was disposed via the thermally sprayed insulating layer on the heat dissipation board. It may also be made to float.

As described above, according to the present invention, it is possible to provide a semiconductor device +1 with a small width portion and high heat dissipation effect without deteriorating the device characteristics.

[Brief explanation of the drawing]

Figure 1 shows the circuit of Sanwa AC ZA system V1, ν1,
Figure 2 is a sectional view showing how a conventional semiconductor device is attached to an automobile generator, Figures 3 and 4 are exploded views showing the structure of a conventional rectifier v, and Figure 5 is a conventional 6 to 8 are perspective views showing a semiconductor device according to an embodiment of the present invention in the order of assembly steps, and FIG. 9 is a sectional view of a semiconductor device according to an embodiment of the present invention. 10 and 11 are a cross-sectional view and a 117-plane view illustrating a state f in which a semiconductor device according to the present invention is attached to a generator. 4a, 4b, 5a, 5b,
6a, 6b...-diode, 22b
, 23b, 24b... Input cuff ji pole, 25'... Rod-shaped electrode, 26'... Ground terminal for cone capacitor, 27
, 28. ．． 30...Thermal sprayed metal layer, 29...Thermal sprayed insulating layer, 31...Substrate, 36...Rig-like part, 38...
・Cover, 39...Plastic molded parts, 40
...first flat electrode, 41...second flat electrode, 42.
...Insulating resin part, 44...Adhesive. Applicant's Representative Patent Attorney Takehiko Suzue Figure 6 Figure 7 Figure 8 Figure 9 Figure 10 Town 1 Figure 11

Claims (3)

[Claims] (1) A sprayed insulating layer is formed on one surface of the heat dissipation board and the metal substrate, a first conductive layer pattern is formed on the sprayed insulating layer, and a second conductive layer is formed on the area where the sprayed insulating layer is not formed. The heat dissipation substrate on which the turn is formed, the semiconductor element attached on each of the first conductive layer pattern and the second conductive layer turn, and the semiconductor element are hermetically sealed in a dry atmosphere. A semiconductor device comprising: a sealing cover; and a terminal electrode electrically connected to the semiconductor element and drawn out from the restraining cover. (2) The semiconductor element is a plurality of diodes, and the first
．． Third. One electrode portion of the fifth diode is fixedly connected to the first conductive layer ie turn, and the second. i4. The other electrode portion of the sixth diode is fixedly connected to the second conductive layer pattern, and the first terminal electrode on the input side is connected to one of the other electrode of the first diode and the second diode. Similarly, the second electrode on the input side
A terminal electrode is connected to the other electrode of the third diode and one electrode of the fourth diode, and a third terminal electrode on the input side is connected to the other electrode of the fifth diode and one electrode of the sixth diode. 2. The semiconductor device according to claim 1, wherein the semiconductor device is connected to the heat dissipating substrate, and the back surface of the heat dissipation substrate constitutes an output terminal electrode on the other electrode side of the circuit including the diode. (3) The semiconductor device according to claim 1 or 2, wherein the other surface of the heat dissipation substrate is a contact surface with an external case.