JPS5946051A - Insulated type semiconductor device - Google Patents

Abstract

PURPOSE:To obtain an insulated type semiconductor device, which is not deformed and damaged and radiation to a side surface thereof is also excellent, by soldering a semiconductor device on a metallic plate soldered on an Al2O3 plate, setting up the Al2O3 plate in the opening section of a protective plate made of copper and filling an air gap section with an insulating resin. CONSTITUTION:Openings 110a, 110b to which a stepped difference is formed are formed to the copper plate 1 in 10mm. thickness. On the other hand, the two metallic plates 3 in approximately 2mm. thickness are soldered on the metallized surface of the Al2O3 plate 2 in approximately 0.1mm. thickness, and SCRs 401 and diodes 402 are soldered 102 on the metallic plates 3, thus constituting a function section. The function section is bonded with the opening 110a of the copper plate 1 with Si resin adhesives 103, and an air gap between the function section and the opening section 110b is filled with the epoxy group insulating resin 6. According to the constitution, radiant property is improved while the insulated type semiconductor device hardly getting trouble due to thermal strain and thermal fatigue is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application] The present invention relates to an insulated semiconductor device, and particularly to a structure in which a semiconductor substrate and a support member for supporting the semiconductor substrate are electrically PH-depleted. The present invention relates to an insulated semiconductor device.

[Prior art]

Conventionally, #'! was often formed on the supporting portion H of a semiconductor device so as to also serve as one electrode of the semiconductor device (if).

In recent years, all electrodes of semiconductor devices have been electrically insulated from metal supporting members, and this has made it possible to
A device has been developed that is configured to increase the degree of freedom in circuit application of t.

For example, an insulating triac is one in which a bidirectional 31M5 child thyristor (triac) substrate is mounted on a ceramic plate, and the ceramic plate is enclosed in a metal package. All electrodes of the triax are
It is insulated from the package by a ceramic plate and pulled out to the outside.

Therefore, the pair of main Tg and poles can be electrically floated from the ground potential on the circuit, and the package can be fixed to the ground potential section regardless of the electrode potential, making it easy to mount the semiconductor device.

In addition, in a hybrid integrated circuit device or a semiconductor module device (hereinafter collectively referred to as hybrid IC), a certain number of electrical circuits including a semiconductor element and a disconnected circuit are generally connected to each other. It is necessary to electrically insulate at least a part of the hybrid IC from a supporting member of the hybrid IC or a metal part such as a heat dissipating member.

In a typical hybrid IC, the above-mentioned insulation is achieved by disposing an insulating layer of explosive material or organic material on a supporting member of 42 metal, and assembling a predetermined electric circuit on this insulating layer. A hybrid IC having such a configuration is also a type of insulated semiconductor device.

On the other hand, in order for a semiconductor device to operate safely and stably, it is necessary to effectively dissipate 2-4, which occurs during the operation of the semiconductor device, to the outside of the package.

This heat dissipation is normally achieved by transferring heat from the semiconductor substrate, which is the heat source, to the air through the members bonded to the semiconductor substrate.

Therefore, in the heat conduction path of the insulated semiconductor device, there are a supporting member, a backing material layer between the supporting member and the insulating layer, the insulating layer, an adhesive layer between the insulating layer and the semiconductor substrate, etc. Includes 1.

In fact, the higher the voltage handled by a circuit including a semiconductor device, or the higher the required reliability (stability over time, moisture resistance, heat resistance, etc.), the more perfect insulation is required. be done.

The above-mentioned heat resistance is effective when the temperature around the semiconductor device increases due to external causes, or when the semiconductor device handles a large amount of power.
It is also required when the heat generated in the semiconductor substrate increases.

If the heat generated within the insulated semiconductor device is relatively small and the required voltage resistance and reliability are not very high, there is no problem in using any material as the insulating layer or adhesive layer.

However, in cases where heat generation is large or reliability requirements are high, inorganic materials such as ceramics are generally selected for the insulating layer. In addition, as the adhesive layer, for example, a metal solder such as lead-tin solder is selected. In an insulated semiconductor device, an insulating layer is provided on a support member that mechanically protects the insulating layer, absorbs heat transferred via the insulating layer, and effectively releases it to the outside. Installed.

The advantage of this support is that the mechanical strength of materials such as copper is high;
In addition, a metal with high thermal conductivity is used. However,
This total 1f strain and the insulating layer are significantly different.

For example, if the insulating layer is alumina, the coefficient of thermal expansion is 6.3.
X 10-67G, whereas the coefficient of thermal expansion of rust is extremely large at 18 X 1 o"7°C.

The first problem is caused by this difference in thermal expansion coefficients, and occurs when an insulating layer is soldered onto the above-mentioned support member during the manufacture of a 61f1 edge type semiconductor device. That is, t-soldering is carried out by laminating the supporting member and the insulating layer via the solder layer, raising the temperature to the melting point of the solder or higher, and then cooling them to room temperature.

In the cooling step, each member is fixed to each other at the solidification point of the solder. Thereafter, each layer contracts according to its own coefficient of thermal expansion while being fixed by solidified solder.

At this time, the amount of shrinkage of the parts differs depending on the difference in the thermal expansion coefficients mentioned above, and so-called thermal strain remains in the bonded parts of each part.

When thermal strain is relatively small, it is absorbed by the solder layer, which is the softest member, but when there is no enough to absorb it, K
This results in deformation of each exposed member.

In particular, deformation or warping of the supporting parts A and I may become an obstacle when encapsulating the semiconductor substrate with air, or the insulated semiconductor must be
This may impede the adhesion when attaching 11y to the heat dissipating means'.

The second problem arises when this gentleman's semiconductor device is used. In other words, f1'- is used for the energizing and resting operations of the semiconductor device.
For the above-mentioned adhesion@, high temperature conditions (approx.
The low temperature condition (ambient temperature epidemic) causes repeated pain.

In this way, each member is in a state of repeating high width and low width (one cycle is called a heat cycle).

Expansion and contraction are repeated based on their unique coefficient of thermal expansion.

Since each member is fixed to each other, differences in expansion and contraction based on differences in thermal expansion coefficients of each member appear as thermal strain applied to the solder layer, which is the softest member.

As the number of heat cycles increases, tensile strain and compressive strain of 7 degrees Fahrenheit occur periodically in the solder layer, which gradually becomes brittle, eventually leading to the occurrence of a thermal fatigue stress J phenomenon.

For example, cracks occur in the solder layer, causing a decrease in adhesive strength, a decrease in thermal conductivity, and the like. These two conditions are particularly noticeable on the exposed end face of the solder layer.The third problem is related to heat dissipation. Generally, in an insulated semiconductor device, an airtight sealing means is used to seal a semiconductor substrate mounted on a support member, wiring members, insulating layers, etc. around the semiconductor substrate.

The hermetic sealing means usually includes a frame made of epoxy resin or the like provided on the support member, and a hollow portion formed by the frame and the support member filled with epoxy resin or the like.

In such a sealing structure, the side surfaces of the frame are directly exposed to air, but epoxy resin and the like have very good thermal conductivity, that is, high thermal resistance. Therefore, it is not possible to expect much effective heating from the sides, and heat is mainly applied from the side that is not in contact with the epoxy resin or the like.

However, if heat is radiated only from the surface that is in close contact with the epoxy resin, the heat dissipation performance is significantly inferior. At the same time, in order to use such a sealed M structure, 1. A dedicated frame is required.

〔the purpose〕

Objectives V and 11 of the present invention: Solve the above-mentioned problems, reduce thermal distortion that occurs during manufacturing or operation, eliminate the risk of deformation, degeneration, or damage of each member, and improve heat dissipation in the lateral direction. An object of the present invention is to provide an insulated semiconductor device.

〔overview〕

In order to achieve the above object, the present invention adheres a metal plate to an inorganic insulating member using a metal solder, and furthermore, the metal plate is bonded to the metal plate using a metal solder. .

Glue the protective member to the protective member and open the protective member so as to penetrate through both main surfaces of the flat metal plate. The feature is that the functional section is attached to the section, and the space formed between the opening for the security section and the functional section is filled with an insulating resin.

Further, the present invention is characterized in that the peripheral part of the useless q'f insulating member for forming the functional part and the circular part of the opening 1 of the flat metal are bonded together with a resin adhesive.

In the present invention, the metal plate serves as a conductive path to the semiconductor substrate and 1.ζ heat generated in the semiconductor substrate. jl)i.

For example (
1. Works as a heat diffusion plate that effectively transmits heat to the heat dissipation means of the heat dissipation fin pj;

The insulating member not only electrically insulates the above-mentioned functional parts from heat dissipation force, but also forms a main heat conduction path to the heat dissipation means.

The protection member 6φ electrically and mechanically protects the functional part from the outside world (for example, protects it to the extent that it can withstand normal external forces), and also protects the functional part from the heat generated in the semiconductor substrate.
It acts as a means of dissipating heat from the sides into the air.

In the present invention, as described later, the above-mentioned first and second
, and in order to solve the third problem, the following measures were taken.

(1) From the perspective of improving heat dissipation, the heat dissipation path was made multifaceted.

(2) From the viewpoint of reducing thermal distortion caused by the difference in the number of tensioners in each part, the integrated area (area of the contact part) between the functional part and the protective member was made as small as possible.

〔Example〕

Hereinafter, the present invention will be explained in more detail by taking an example of hybrid ■Cf.

FIG. 1 is an exploded perspective view of the main parts of a 1200-60A class hybrid IC according to an embodiment of the present invention, and FIG. 2 is a circuit diagram of the embodiment. In the figure, two metal plates 3 are lined up and in contact with an alumina plate 2.

On the metal plate 3, a thyristor 4 and a flywheel diode 402 are soldered, respectively.
1 and a flywheel diode 402 constitute a functional section 5)1. ing.

The functional section 5 is attached to the protection member 1 having first and second openings 110FK110b provided through both main surfaces of the plate metal. The space formed by the second opening 110b and the functional part 5 attached thereto is filled with an insulating resin. Adhesive materials (metal soldering for soldering) and filling resin between each member are not shown.

A circuit as shown in FIG. 2 is assembled on the metal plate 3 mentioned above. That is, the thyristor 401 and the flywheel iode 402 are connected to the wiring wire 440 shown in FIG.
They are connected by a wiring metal piece 430 as shown in FIG.

41 old, 4j02 and 4103 are external terminals, respectively. The external terminal 4101 is placed directly on the metal plate 3. The external terminals 4102 and 4103,
It is glued onto an insulating alumina plate 420 glued onto the metal plate 3, and placed on a metal piece 430 for wiring.

FIG. 3 shows a schematic cross-sectional view of the shelf 1 according to one embodiment of the present invention.

In FIG. 3, external terminals 4101, 4102 and 4103, wiring wire 440, metal piece 430, and insulating alumina plate 420 are omitted from functional section 5 to simplify the drawing.

1; Ri θ Member 1 is a copper plate with a thickness of Joy, and a width of 40
The center part of the same member has a first opening 110a with a width of 36 mm, a length of 7 mm, and a height of 0.5 mm, and a width of 29 mm and a length of 68 mm. Tomo, ljisa 9.5
The second opening of the battle is formed by the moon Ob and the 1st opening]
A 1"1 through hole is formed in the shape FJv between the 0 part 110a and the 21st part 110b.

On the other hand, one side JJ of the -r lumina plate 2 of the machine fil bottom part 5
T-2 pieces of gold iri 41j 3 is 40φ, lead-60L
l) ('',H's own'!, I Ir1 bonded by layer 101. i)!l 1ltF 1st II
J'7i of solder layer 101 is approximately 0.1 mm.

The adhesion surface of the alumina plate 2 is subjected to a well-known metallization process (wettability against rind)9.

Alumina plate 2 has a width of 35 mm, a length of 70 mm, and a thickness of 0.41 f.
f7! , the metal plate 3 has a width of 26 mm, a width of 31 mm,
It is 2mm thick.

A thyristor 401 and a diode 402 are placed on the metal plate 3.
are electrically conductively adhered by a second solder layer 102 having the same composition and thickness as the first solder layer 101 described in -1. ing.

Here, the thyristor 401 has an area of 15 x 10- and a thickness of 0.36 mm, and the diode 402 has an area of 5 x
5- and a thickness of 0.2 myt. The functional unit 5 configured in this manner has the above-mentioned width of 36 m, length of 71 m,
It is bonded to the first opening 110a of the 05 mm thick plate with a resin adhesive 103.

The space formed by the functional section 5 and the second opening 110b is filled with an insulating resin 6. The resin adhesive 103
is a silicone resin, and the insulating resin 6 is an epoxy resin.

A heat dissipation fin 1 is provided on the bottom of the alumina plate 2 and the protective part 1.
11 are provided.

The important point in this configuration is that it is transmitted to the functional section 5 and F'.
The holding member 1 made of metal with excellent compatibility is integrated with a soft resin adhesive 103 in a small area around the periphery of the alumina plate 2, which is suitable for a structure that does not easily cause thermal distortion. In addition, the surface of the alumina plate 2 on the side where the functional section 50 circuit is formed is connected to the second opening 110b of the metal support member 1.
This part is filled with insulating resin 6 to protect the circuit electrically and m'4m.

Furthermore, the lightning of the reversibility member l and the alumina plate 2,
A heat dissipation means, that is, a heat dissipation fin 111, provided to be in direct contact with the surface opposite to the surface on which the air circuit is formed.
This is because heat is dissipated from multiple sides.

In experiments conducted based on this example, it was possible to improve heat dissipation and at the same time reduce failures due to thermal strain and thermal fatigue. A specific example thereof will be explained below.

First, the thermal resistance from the thyristor 401 to the alumina plate 2 in contact with the heat dissipation means in the hybrid IC of this example is 0.15
℃/W.

This value is determined by mounting the same functional unit 5 as in this example on a copper plate (supporting member) with a width of 40 mm, a length of 92 mm, and a thickness of 3.2 mm. Compared to the case of a hybrid IC (comparative example) in which the liquid is packed in a resin case and the same case is filled with resin,
Approximately 40% lower.

In addition, the thyristor 401 of the hybrid IC of this embodiment has a power of 200W.
The temperature rise when power loss occurred was about 30°C, and in the case of the comparative example it was about 50°C. In other words, in the hybrid IC of this example, the filled
It has a structure in which the periphery of the rudder is surrounded by a retaining member 1 with good thermal conductivity, and in practical terms, the rudder retainer (member 1 functions similarly to a heat dissipation means, so heat dissipation is efficient and As a result of multifaceted efforts, the above-mentioned performance was obtained.

Next, Figure 4 shows the results of externally tracking the thermal resistance of the hybrid IC of this embodiment by applying a heat cycle.

The number of heat cycles is plotted on the axis of the figure, and the thermal resistance is plotted on the vertical axis. The heat cycle was performed by varying the temperature from -55°C to +150°C.

In the figure, line A shows the result of the hybrid IC of this example, and line B shows the result of the above-mentioned comparative example.

As is clear from the figure, the ? In the 11° IC, no increase in U1 thermal resistance was observed up to 700 heat cycles. On the other hand, in the hybrid IC of the comparative example, an increase in thermal resistance was observed after 200 heat cycles, and a difference between the two was clearly found.

In the case of this example, unlike the structure of the comparative example described above, there is no adhesive part over a large area between the alumina support members that are likely to cause thermal fatigue failure, and this is a factor that increases thermal resistance. One has been removed.

The alumina plate 2 is integrated with the protection member 1 by a soft resin adhesive 103, and the resin adhesive 103 is effective in reducing thermal distortion due to the difference in coefficient of thermal expansion between the alumina plate 2 and the protection member 1. - to absorb.

As a result, the internal stress of the alumina resin 2 itself is reduced 1, and as a secondary effect, the influence on the solder layer 101 is also reduced. The obvious difference found in the results due to the heat cycle described above is due to these circumstances.

The shredded hybrid IC of this example was also excellent in terms of warpage and airtightness of the seal. For example, the warpage of the alumina plate 2 that comes into direct contact with the heat dissipation means (the radius of curvature of the exposed plane of the alumina plate 2) is as long as 380 cm.

Even when the hybrid IC was exposed to In in an atmosphere with a relative humidity of 90% and a flow rate of 6oC for 10 hours, there was no abnormality in the electrical performance of the hybrid IC.

In the song, in the hybrid IC of the real Afli example, the functional unit 5 and the
The space formed by the JQ part 1 was filled with an insulating resin 6.

In other words, since the functional section 5 and the protective member 1 also serve as a container for resin filling, a dedicated frame is not required.

This point is also 4 for the hybrid IC of this embodiment! ) A) It is a side effect of tq.

Various modifications of the present invention will be illustrated below.

The present invention can be implemented in various ways in addition to the embodiments described above.

In this example, a composite plate was used as the metal 1113. However, this is not limited to stiffness, and even if the heat dissipation of the hybrid IC is reduced to some extent, the first and second d
In order to further improve the reliability by alleviating the thermal fatigue of solder M], 01.102, a metal whose PAjll tensile coefficient is close to that of the alumina plate 2 or the semiconductor substrate may be used.

For example, it is preferable to use materials such as molybdenum, tungsten, or anchor 1-invar A4 clad composite gold dove or instep-carbon fiber bonded metal.

Further, it is preferable to form a metal film of nickel or the like on the soldering surface of the seam 1 of the above-mentioned national board 3 by plating or the like in order to reduce solder wettability.

Next, as the ml-free insulating material, in addition to alumina, aluminum nitride (AIN), bromine ninede (BN), silicon carbide (SiC), silicon nitride (Si3N4), beryllium oxide (Bed), etc. A fired product containing it as an ingredient can be used.

In this case, the first solder layer 101 can reduce the thermal resistance.
From the viewpoint of reducing thermal fatigue, it is also possible to make the inorganic insulating member thinner.

In addition to the composition of 40% lead-60 tin, the solder used in the functional part 5 may be, for example, 95 titanium lead-5% tin, or a third component of the solder may be silver, indium, zinc, or bismuth. etc. can be used. Its thickness is also 0
．． The thickness is not limited to 1 mm, and may be thicker or thinner.

As the semiconductor substrate mounted on the metal plate 3, any semiconductor element (including those using semiconductors other than silicon, such as germanium, gallium arsenide, etc.) can be used. It goes without saying that any circuit configuration can be constructed.

Further, the circuit elements mounted on the metal plate 3 are not limited to semiconductor elements, and passive elements such as resistors and capacitors may also be mounted without any problem.

Furthermore, the number of semiconductor substrates mounted on the metal plate 3 does not necessarily have to be plural.

As the adhesive used to integrate the inorganic insulating member and the securing member, it is more preferable to use a soft resin such as silicone resin in order to alleviate strain between the two members. However, it is not necessarily necessary to use KIII, and for example, adhesives such as Evogishi adhesive or silicone gel may be used.

The insulating resin 6 and [7 filled in the space between the functional part 5 and the second opening 110b are not limited to epoxy resins, and include, for example, silicone resin, silicone gel, etc. Alternatively, if necessary, a structure in which these insulating resins are filled in a layered manner may be used.

Prompt W! It is preferable to use copper for mechanical strength and thermal conductivity for the first and second parts, but depending on the performance required of the insulated semiconductor device, for example, aluminum, iron,
Brass, iron-nickel alloy, silicon carbide, etc.
Other metals may also be selected.

In this case, in order to improve heat dissipation in the lateral direction,
! : It is also possible to provide the member 1 with a means for enlarging its surface area.

〔effect〕

As explained above, the present invention adheres a metal plate onto an inorganic insulating member using a metal solder, and further attaches a semiconductor substrate to the protrusion 1 [metallic bending plate] 2 using a metal solder. (Constructed by gluing) 1. CINN
lj part is formed, f is also attached to the opening of the protective part 7, and the space σi formed between the opening part and the functional part is filled with an insulating resin, and 8. The opening between the peripheral part of the insulating member and the flat metal cBτ1
Improves dissipation properties 1, prevents degeneration or deterioration of parts due to thermal strain
This has the advantage of eliminating the fear of Z1 destruction.

[Brief explanation of the drawing]

FIG. 1 shows the essential γ′411 decomposition 1;゛1 of an embodiment of the present invention.
Sugi-11, <11 Figure 2 shows the circuit of the above embodiment (■), 3rd
1'J: ↓A schematic sectional view of FIG. 1, and FIG. 4 is a diagram showing the results of an experimental example in which E1 was obtained based on the actual JA example. ■・・・(♀For some parts 2...Alumina plate, 3...Metal plate, 5...Driving part, 6...Insulating resin, 101...
・Jth solder layer, 102...Second solder layer, 103・
...Resin adhesive, 401...Thyristor, 402...
・Diode meter for flywheel 1 Surrounding fang 2 Decoy 4]○3 Oki 3 Oral fang 4 Diagram

Claims (2)

[Claims] (1) A functional part having a structure in which a metal plate is bonded on an inorganic insulating member using a metal solder, and a semiconductor substrate is bonded using a metal solder on the gold plate, and a flat metal plate. A crushing member is provided with an opening extending through both main surfaces of the protection member, an upper functional part is fixed to the opening, and the protection member is formed by the opening of the protective member and the functional part. An insulated semiconductor device characterized in that a space is filled with an insulating resin. (2) The insulated semiconductor device according to item 1 of the patent scope, wherein a peripheral portion of the inorganic insulating member constituting the functional section is bonded to the inner surface of the opening of the flat metal plate using a resin adhesive.