JP2009010213A - Hybrid integrated circuit device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problem of size bulkiness of a hybrid IC device using a metal substrate with the backside of the metal substrate exposed and a heat radiating film provided on the exposed surface. <P>SOLUTION: A desired circuit is achieved by providing a first circuit element group on the surface of a metal substrate 13, and a second circuit element group on the backside of the metal substrate. The surface and backside coating resins, and the side covering resin are formed integrally with a transfer mold. A third arrangement region B on the backside has the substrate backside exposed with a heat radiating film 21 provided therein. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a hybrid integrated circuit device.

  A metal substrate formed using Cu or Al as a main material is adopted as a hybrid integrated circuit device because of its excellent heat dissipation. For example, power-related devices increase the temperature of the device itself and drive capacity decreases, but by adopting a metal substrate, the temperature rise can be suppressed, and eventually, the drive capacity is reduced while suppressing energy loss. Therefore, it is possible to reduce electric power and environmental load.

  An example is shown in FIG. For example, there is an Al substrate 1, and an oxide film 2 formed by alumite treatment is formed on both surfaces thereof. The surface of the substrate 1 is further covered with an insulating resin layer 3, and a wiring pattern 4 is provided thereon. The wiring pattern 4 includes islands, wirings, electrode pads, lead pads, and the like. The semiconductor element 5 is fixed on the island, and the electrode of the semiconductor element 5 and the electrode pad are electrically connected through a fine metal wire. Further, chip capacitors and chip resistors are soldered to the electrode pads as passive elements.

  Therefore, a hybrid integrated circuit is realized by the semiconductor element, the passive element, and the wiring pattern 4. Further, if necessary, the lead is connected to the lead pad, and the whole is sealed with the insulating resin 6 to be completed.

Examples of related technical literatures include the following patent literatures.
JP 2003-318333 A

  However, in order to improve heat dissipation, the heat dissipation fins 7 are mounted on the back surface of the metal substrate 1.

  This is because the alumite surface or the Al surface from which the alumite has been removed is exposed on the back surface of the metal substrate 1, so that if the radiation fins 7 are attached, the temperature rise of the semiconductor element 5 placed on the metal substrate 1 Can be suppressed.

  However, as shown in FIG. 5, since the radiation fins 7 are large so as to cover the entire back surface of the metal substrate 1 (shown by dotted lines), the size of the hybrid integrated circuit device itself increases, and this hybrid integrated circuit device is mounted. The set 8 itself cannot be reduced in size.

  Further, in the type in which the back surface of the metal substrate 1 is exposed, the interface between the metal substrate and the insulating resin 6 is peeled off on the back surface due to the difference in the thermal expansion coefficient α between the metal substrate 1 and the insulating resin 6, and moisture and the like enter. There was also a problem that reliability was lowered.

In view of the above, the hybrid integrated circuit device of the present invention is
First, a metal substrate having a front surface, a back surface and side surfaces;
A first insulating resin layer covering the surface; a second insulating resin layer covering a region of the back surface;
A first conductive pattern provided on the first insulating resin layer; a second conductive pattern provided on the second insulating resin layer;
A plurality of first circuit elements electrically connected and fixed to the first conductive pattern;
A plurality of second circuit elements electrically connected and fixed to the second conductive pattern;
A lead that electrically connects the first conductive pattern and the second conductive pattern and is provided across a side surface of the metal substrate;
The problem is solved by comprising a first coating resin for coating the first circuit element and a second coating resin for coating the second circuit element.
Since the heat radiation fin and the second circuit element are mounted on the back surface, the mounting efficiency is improved.

Second, the coating resin is solved by being coated with a transfer mold.
Third, the first coating resin and the second coating resin are integrated with each other through the side surface, so that the metal substrate is sandwiched between the front and the back, and warpage can be suppressed.

Fourthly, the problem is solved by attaching a radiation fin to the other region of the back surface.
Fifth, the metal substrate is arranged vertically, the second coating resin is located below the vertically arranged metal substrate, and the heat dissipating fin is located above.

  Since the heat released from the fins rises, the circuit element is not arranged in this rising path, so that the influence of temperature can be suppressed.

  Since circuit elements and heat radiation fins are attached to the front and back surfaces of the metal substrate, a hybrid integrated circuit device having a high mounting density can be realized.

  When a hybrid integrated circuit device is mounted upright, a circuit element is disposed on the lower surface and a heat radiation fin is disposed on the back surface. The heat generated from the heat radiation fin rises without passing through the circuit element. The influence of can be suppressed.

  In addition, since the front and back surfaces are integrally sealed with a transfer mold, the shape is sandwiched with substantially the same thermal expansion coefficient, and warpage is suppressed. Therefore, even if there is an interface between the insulating resin and the metal substrate on the rear surface of the metal substrate, peeling can be suppressed.

  Hereinafter, the best mode of the present invention will be described.

  FIG. 1A shows a hybrid integrated circuit device 10 mounted on a mounting board 11 such as a printed board, and is generally called a module 12.

  First, the hybrid integrated circuit device 10 will be described. First, the substrate 13 is a metal substrate whose main material is Cu, Al or Fe. If necessary, an alloy such as stainless steel may be used.

  For example, when an Al substrate is employed as the metal substrate 13, in general, the surface is subjected to alumite treatment or oxidation treatment in consideration of insulation resistance and wear resistance. Moreover, this oxide film also has good adhesion to the insulating resin layer 14 to be further laminated. However, you may laminate | stack the insulating resin layer 13 directly on Al surface without an oxide film.

  The metal substrate 13 on which the oxide film is formed is solidified by pressing from a large plate, so that it is rectangular when viewed in plan, and the four side surfaces extending from the front and back periphery are exposed to Al metal. Is done.

  On the other hand, in the case of Cu, the oxide film is not substantially formed because it has poor adhesion to its own metal compared to the Al oxide film.

  The surface of the metal substrate 13 is covered with the insulating resin layer 14 described above in consideration of the insulation of the conductive pattern. The insulating resin layer 14 is generally selected and mixed with fillers such as Si and Al2O3 in consideration of pressure resistance, thermal expansion coefficient α, and the like, or glass fibers and the like are woven.

  Here, the insulating resin layer coated on the surface of the metal substrate 13 is referred to as a first insulating resin layer 14F, and the insulating resin layer coated on the back surface is referred to as a second insulating resin layer 14B.

  A first conductive pattern 15F is provided on the first insulating resin layer 14F. The conductive pattern 15F is generally made of Cu, and is formed into a desired pattern by etching after the entire surface Cu foil provided with an adhesive is bonded by thermocompression bonding. However, the conductive paste may be printed by screen printing to form a conductive pattern.

  On the other hand, the second insulating resin layer 14B is also bonded using the same material as the first insulating resin layer 14F, and the conductive pattern 15B is formed by the same method.

  These first and second conductive patterns 14 are provided with an island 16, an electrode pad 17, a wiring integral with the island or the electrode pad or an island shape, an electrode 18 for mounting a passive element, a lead pad 19, and the like. .

  Furthermore, the semiconductor element 20 is fixed to the island 16, and the pad electrode provided on the surface of the semiconductor element and the electrode pad 17 are electrically connected through a fine metal wire. Here, as the semiconductor element, a discrete semiconductor element, an LSI, or the like can be considered. Here, these elements arranged on the front side of the metal substrate 13 are referred to as a first circuit element group, and a substantially entire surface on the front side is defined as a first arrangement region. Furthermore, the active element and the passive element arranged on the back surface of the substrate 13 are referred to as a second circuit element group, and the region in which these second circuit element groups are arranged is referred to as a second arrangement region. Furthermore, let the arrangement | positioning area | region of the radiation fin 21 be a 3rd arrangement | positioning area | region.

  A power-type semiconductor element 22 is mounted on the surface of the metal substrate 13 corresponding to an installation portion of the radiating fins 21 described later. This releases the heat of the power semiconductor element 22 to the outside through the heat radiation fin 21 and suppresses the heat generation of the semiconductor element 22 itself. As a result, the driving capability is increased, and wasteful power can be saved. As an example, a power system discrete element, a power MOS, a power TR, an IGBT, a GTBT, a power system LSI, or the like can be considered.

  In other words, the first circuit element group includes circuit elements that require a radiator, such as the power semiconductor elements described above, and circuit elements that do not require a radiator, such as a control circuit, a protection circuit, It can be divided into passive elements.

  On the other hand, the hybrid integrated circuit device 10 is mounted vertically with respect to the mounting substrate 11 as shown in FIG.

  That is, a preferable arrangement is determined by the route of the heated gas of the radiating fins 21. Here, the radiating fin 21 is shown in FIG. 1A so that the groove 23 runs from the front to the back with respect to the paper surface. This is the radiating fin in FIG. I wrote this to show you something. Actually, they are arranged as shown in FIG. For example, the rear surface of the plasma TV or the liquid crystal TV is opened and placed on the metal chassis SH that can be seen there. That is, the chassis SH is a hand that is arranged perpendicular to the floor, with the base point of the arrow pointing downward and the tip of the arrow pointing upward. As is apparent from the drawing, the groove 23 runs from the bottom to the top with respect to the paper surface. This is because air flows from the bottom to the top as indicated by the arrows, and the heat efficiency is high.

  If it is this structure, naturally the lower air is warmed by the radiation fin 21, and the warmed air rises as it is. Therefore, if the circuit element is arranged on the side where the air is warmed and raised, the temperature of the circuit element is increased, but the present invention is reversed.

Further, when the hybrid integrated circuit device 10 is vertically (vertically arranged) with respect to the mounting substrate 11, the radiation fins 21 are arranged on the upper side of the back surface of the metal substrate. A margin is provided around the metal substrate. Although the back surface of the metal substrate does not occupy 100% in the second arrangement region and the third arrangement region of the radiation fins 21, it can be almost divided into two in the second circuit element arrangement region and the arrangement region of the radiation fins 21.
Therefore, as shown in the left of FIG. 1B, if the second arrangement region is A, the third arrangement region of the radiation fins 21 is B, and the radiation fins 21 are larger than the width of the metal substrate 13, the vertical substrate On the back surface, it is important to arrange the second arrangement area A downward and the third arrangement area B upward. If the heat dissipating fins 21 are smaller than the width of the metal substrate 13, the right side of FIG. In this case, a slight space is formed as the second arrangement region on the left and right of the heat radiation fin 21, and a part of the second circuit element group may also be arranged here.

  Subsequently, in FIG. 1, there are lead pads 19 on the lower ends of the front and back of the substrate, and leads 24 are provided here. The lead 24 electrically connects the circuit on the front side and the circuit on the back side of the board, and further carries out electrical connection with the mounting board. Further, this lead enables vertical insertion with respect to the mounting substrate 11. In the drawing, clip terminals are adopted. In this clip terminal, conductive members extend from the front and back sides of the metal substrate 13, and are integrated into one lead outside the lower end of the metal substrate. However, if vertical insertion is possible, the conductive members may be extended from the front and back sides of the metal substrate 13 and may be extended to the outside of the lower end of the metal substrate as they are. In this case, the front and back electrical connections are made on the mounting substrate 11 side. As a matter of course, a plurality of these leads are provided on the front and back sides.

  Furthermore, since the first circuit element group and the second circuit element group are arranged in the first arrangement area and the second arrangement area of the metal substrate 13 as described above, insulation is provided for environmental resistance. Coating resin 25 is coated. Methods include potting, dipping, transfer mold using upper and lower molds, injection mold, and the like. Here, transfer mold is realized in consideration of reliability. When molding with the upper and lower molds, the first and second arrangement regions become mold cavities, and the third arrangement region B is brought into contact with the upper or lower mold.

  Therefore, in the third arrangement region B, Al of the Al substrate, the oxide film on the surface thereof, or the insulating resin layer 14 is exposed. Of course, when thermally coupled to the radiating fin 21, the thermal resistance increases in the order of the exposed surface of Al, oxide film, and insulating resin layer 14. Therefore, it is selected in consideration of the amount of heat of the circuit and the insulation of the radiating fin, but generally Al or an oxide film is exposed.

  This exposure point is a feature of the present invention. Referring to FIG. 1, when the hybrid integrated circuit device 10 is mounted upright on the mounting substrate 11, a circuit element is disposed on the lower surface of the metal substrate, and a radiation fin 21 is disposed on the lower surface. Since heat rises without passing through the circuit elements, the influence of temperature can be suppressed. Therefore, if the semiconductor element of the first circuit element group on the front side of the metal substrate, which generates heat, and generates more heat than other elements, is placed on the back side of the heat dissipation fin, the driving capability of this semiconductor element is improved. it can. In addition, the heat generated from the radiation fins 21 does not affect other elements.

  2 and 7 illustrate an example in which the front surface, the back surface, and the side surfaces of the metal substrate are all sealed except for the third arrangement region B. FIG. 2A is a cross-sectional view and FIG. 2B is a perspective view. Al of metal substrate of Al is 25 × 10 −6 / degree C, chip capacitor, chip resistance is 7 to 10 × 10 −6 / degree C, semiconductor chip is 3.5 × 10 −6, and is a coating resin The epoxy resin is 50 × 10 −6 / degree C. In particular, α differs greatly between the metal substrate and the coating resin, and the electrical connection portions of the semiconductor chip and the passive element are broken or cracked. Therefore, the amount of the inorganic filler is adjusted, and the sealing epoxy resin is adjusted to about 15 to 20 × 10 −6. In consideration of α of the metal substrate and α of the element to be mounted, α of the epoxy resin is preferably about 15 to 20 × 10 −6. Therefore, the stress due to α difference can be considerably eliminated.

  Next, considering the adhesion between the resin and the substrate, the adhesion improves in the order of Al, oxide film, and insulating resin layer 14. In addition, since the alumite film, which is an oxide film, is realized by anodic oxidation, it is generated on the surface of Al, and therefore has excellent adhesion. However, the heat resistance is higher than that of Al, and the hardness is higher than that of Al or the resin layer 14, and the wear of the press blade and the drill is severe in the processing of a press machine, a drill or the like. Moreover, since the back and front of the metal substrate are subjected to alumite treatment at the same time, basically, they are simultaneously generated on the back surface. Therefore, the third arrangement region B on the back surface of the metal substrate 13 leaves the alumite film as it is, and this alumite film is exposed after the transfer molding.

Further, when Al is left as the third arrangement region, if the back surface of the metal substrate 13 is covered with an oxidation protection film and only the surface of the metal substrate 13 is anodized, the back surface of the metal substrate becomes Al. By forming the insulating resin layer 14 in the second arrangement area A and performing transfer molding, Al is exposed in the third arrangement area B.
In this case, the adhesion between Al and the insulating resin layer is poor, and countermeasures are required.

  Therefore, as will be described with reference to FIG. 2, the present invention exposes the third arrangement region B and seals the other parts.

  FIG. 7 illustrates this manufacturing method. On the metal substrate, the first circuit element group and the second circuit element group are already arranged, and leads 24 are also provided. This metal substrate is placed in a transfer mold (or injection) mold and resin-sealed. Here, there are an upper mold 30A and a lower mold 30B, and both are fitted to form a cavity 31. Here, the clip terminal 24 is employed. In this clip terminal, conductive members 32 and 33 extend from the front and back of the metal substrate 13, respectively, and are integrated with the connecting member 34 outside the lower end of the metal substrate to form one lead.

  In the present invention, this connecting member 34 is also resin-sealed. Further, except for the third arrangement region B, the metal substrate 13 is sealed including the front surface, the back surface, and the side surfaces. The first coating resin for sealing the first circuit element group and the second coating resin for sealing the second circuit element group are integrated with the resin sealed on the four side surfaces. Therefore, the connection reliability of the clip lead is improved, and furthermore, since the coating resin is integrated including the four side surfaces, the coating resin is not peeled off from the substrate. Further, when the substrate is separated from the side surface of the substrate, separation grooves are formed above and below, and the substrate is separated through the groove. Therefore, when viewed in cross section, the right side surface has a V-shape that is 90 degrees clockwise and the left side has a V-shape that is 90 degrees clockwise. That is, all the side surfaces are convex toward the outside at an obtuse angle from the front surface and the back surface of the substrate. Therefore, the reference numeral 40 in FIG. 2 is the cross-sectional shape of the side surface, and since the coating resin is provided there, the anchor works here as well.

Further, since the same coating resin α is provided on the front and back with the metal substrate as the center, the warpage of the entire module is considerably reduced.
FIG. 3 shows the second embodiment. The difference from FIG. 1 is the shape of the sealing means and the leads, and the rest is the same as the description of FIG. Therefore, only a different point is demonstrated here. In the present invention, a casing is used as the sealing means. Since this is a hollow structure, the curvature by the difference with the metal substrate (alpha) can be reduced.

Further, instead of this casing, it may be formed of a coating resin. However, in this case, since a lump of resin is pasted on the front and back of the metal substrate, compared with the first embodiment, There is a high possibility of peeling at the interface.
Although the heat radiation fin 21 may be in direct contact with Al or the anodic oxide film, a material having insulating properties and excellent thermal conductivity may be provided between the two. In FIG. 1, the heat dissipating fins are metal base fins vertically attached to metal.

It is a figure explaining the hybrid integrated circuit device of this invention. It is a figure explaining the hybrid integrated circuit device of this invention. It is a figure explaining the hybrid integrated circuit device of this invention. It is a figure when the hybrid integrated circuit device of this invention is attached to the panel. It is a figure when the conventional hybrid integrated circuit device is attached to the panel. It is a figure explaining the hybrid integrated circuit device concerning a prior art. It is a figure at the time of carrying out transfer molding using the upper and lower molds according to the present invention.

Explanation of symbols

10: Hybrid integrated circuit device 11: Mounting substrate 12: Module in which the hybrid integrated circuit device is vertically inserted on the mounting substrate 13: Metal substrate 14: Insulating resin layer 21: Radiation fin

Claims (8)

A metal substrate having a front surface, a back surface, and a side surface, a first insulating resin layer covering the surface, a second insulating resin layer covering a region of the back surface, and the first insulating resin layer. A first conductive pattern, a second conductive pattern provided on the second insulating resin layer, and a plurality of first circuit elements electrically connected and fixed to the first conductive pattern; A plurality of second circuit elements electrically connected and fixed to the second conductive pattern, leads for electrically connecting the first conductive pattern and the second conductive pattern, and the first A hybrid integrated circuit device comprising: a first coating resin that covers one circuit element; and a second coating resin that covers the second circuit element. The hybrid integrated circuit device according to claim 1, wherein the coating resin is coated with a transfer mold. The hybrid integrated circuit device according to claim 1, wherein the first coating resin and the second coating resin are integrated with each other through the side surface. The hybrid integrated circuit device according to claim 1, wherein a radiation fin is attached to the other region of the back surface. 5. The hybrid integrated circuit device according to claim 4, wherein the metal substrate is arranged vertically, the second coating resin is located below the vertically arranged metal substrate, and the heat radiating fins are located above the metal substrate. . The hybrid integrated circuit device according to claim 1, wherein the metal substrate is made of a metal whose main material is Al, and an oxide film is formed on a surface thereof. A metal substrate having a front surface, a back surface, and a side surface, a first insulating resin layer covering the surface, a second insulating resin layer covering a region of the back surface, and the first insulating resin layer. A first conductive pattern, a second conductive pattern provided on the second insulating resin layer, and a plurality of first circuit elements electrically connected and fixed to the first conductive pattern; A plurality of second circuit elements that are electrically connected and fixed to the second conductive pattern, leads that electrically connect the first conductive pattern and the second conductive pattern, and the first 1 circuit element and a coating resin that covers and integrally covers the second circuit element,
The metal substrate is arranged vertically, and the first circuit element located above the vertical arrangement is composed of a BIP or MOS type power transistor, IGBT or GTBT, and the first circuit element is arranged in an arrangement region of the first circuit element. A hybrid integrated circuit device, wherein a heat radiating fin is provided on the back surface. The hybrid integrated circuit according to claim 7, wherein oxide films are formed on both surfaces of the metal substrate, and the heat radiation fins are thermally coupled via a heat conductive material provided on the oxide film. apparatus.

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