JP3490780B2 - Hybrid integrated circuit device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hybrid integrated circuit device in which a plurality of substrates are laminated, and more particularly to a structure for reducing warpage or distortion caused by a difference in thermal expansion coefficient or the like.

[0002]

2. Description of the Related Art A conventional structure will be described with reference to FIGS. Generally, a multilayer substrate structure in which a plurality of substrates are laminated is disclosed in, for example, Japanese Patent Application No. 2-201219 (H.
05K3 / 36), a printed circuit board 11 is mounted on the lower substrate 10 to form a multilayer substrate. Conductive paths 12 and conductive lands 13 are formed on the first substrate 10, and chip resistors 14 and semiconductor elements 15 are electrically connected thereto via solder.

The printed circuit board 11 also has a conductive path 1.
Although not shown in FIG. 6 or the figure, a chip resistor and a semiconductor element are connected to the conductive land through solder. As shown in the figure, since the printed circuit board 11 is adhered on the lower layer substrate 10, the mounting component and the mounting density of the printed circuit board 11 are improved, and further, on the back surface of the printed circuit board 11. If mounted, the mounting density can be improved while the size is relatively small.

[0004]

As shown in FIG. 4, since the lower substrate 10 and the printed circuit board 11 are firmly fixed by the adhesive 17 or solder, the two substrates have different thermal expansion coefficients. And various problems occurred. First, although there is no particular problem at the time of fixing, there is a problem that when heat is applied constantly or in a cycle, both substrates warp or the substrates peel off. Further, as described above, when a semiconductor element or an electric component is mounted on the back surface of the printed board 11 in order to realize high density, distortion occurs between the fixing resin and the boards 10 and 11, and a crack occurs in the solder fixing part. , There was a problem that the circuit would malfunction due to the removal of the thin metal wire at the bonding point.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems. First, the first bonding pad and the second bonding pad are provided.
A thin metal wire is bonded between the bonding pads,
This thin metal wire makes it possible to form second wires at predetermined intervals on the first substrate.
The solution is to suspend the board.

Second, the first bonding pad and / or
Alternatively, the second bonding pad is solved by being electrically connected to a circuit. Thirdly, a thin metal wire is bonded between the first bonding pad and the second bonding pad, and the second thin wire is hung on the first substrate at a predetermined interval by the thin metal wire, and the second substrate is hung between the first substrate and the second substrate. The problem is solved by using the provided semiconductor element or circuit component as a spacer between the both substrates by an insulating means provided on the upper part.

[0007]

First of all, generally, fine metal wires are made of Cu, Al and A.
A material such as u has a diameter of about 40 μmφ for a signal line, but a thick material has a diameter of 200 φ to 500 μmφ. Therefore, it is possible to suspend the substrate by wire-bonding the first substrate and the second substrate and pushing the second substrate upward, for example. Even thin metal wires can be easily hung by increasing the number of bondings. Therefore, as a general rule, an adhesive for fixing is not required between the two substrates, and no stress is applied to the two substrates or the elements and components between them, so that warpage, peeling, element deterioration, etc. are eliminated.

If the bonding pad uses a thin metal wire bonded to a general pad connected to a wiring, it can be assembled by a normal process without using a special bonding pad. on the other hand,
If the thin metal wire is thin and the number of wires is small, and there is a problem in hanging the board, it is possible to provide a separate island-shaped bonding pad and hang it with a thick metal thin wire is there.

Thirdly, although the fine metal wire suspends the second substrate, there is a possibility that the second substrate may be lowered if an external force is applied. Therefore, an insulating means is provided on the upper surface of the semiconductor element or the electric component between the first substrate and the second substrate. Even if the second substrate descends for some reason, it can be stopped by this insulating means, and contact between both substrates can be prevented.

[0010]

Embodiments of the present invention will be described below with reference to FIGS. FIG. 1 is a perspective view of an embodiment,
FIG. 2 is a cross-sectional view of a second substrate further laminated on the upper substrate of FIG. First, there is the first metal substrate 30, on which the first conductive paths 31 and conductive lands 32 are attached. The first substrate 30 (this substrate may be a printed circuit board or a ceramic substrate) is made of an Al substrate and has an oxide film 33 formed on its surface. Although this oxide film is formed by anodizing both surfaces by anodic oxidation, it may be formed by thermal oxidation or may be formed by deposition. At least one main surface is covered with an insulating resin 34 having adhesiveness such as epoxy resin or polyimide resin, and the conductive path 31 is attached by hot pressing. The conductive path 31 is made of Cu, and is adhered to the entire surface and then etched and patterned with a ferric chloride solution. The conductive land 32 is an area for fixing the bare chip-shaped first semiconductor element 35 and the like. Here, since a large-signal heating element is mounted, a heat sink 36 such as Cu is soldered on the lower layer of the chip 35. They are fixed to each other via a conductive path or are in an island shape. The semiconductor element 35 may be an IC chip or an LSI chip, but in the case of a power transistor, the base electrode and the emitter electrode on the surface are wire-bonded to a pad integrated with a part of the wiring by a fine metal wire, and the back surface of the chip is a collector. Therefore, it is fixed to the conductive land integrated with the conductive path via solder or the like. Furthermore, a first component 37 such as a chip resistor or a chip capacitor is connected to the conductive path via solder.

On the other hand, there is a second substrate 38 for double-sided mounting,
Here, there is a so-called printed circuit board, which is made of materials such as glass epoxy, paper epoxy, paper phenol and polyimide. However, a ceramic substrate, a metal substrate similar to the first substrate, or a sheet-shaped flexible substrate may be used. For example, the ceramic substrate itself has a multi-layered structure, and the components are densely mounted in many layers. Therefore, when the ceramic substrate is adopted in the structure of the present application, the mounting density can be further improved. Further, when considering only hanging the substrate with a thin metal wire, the substrate is not necessarily a double-sided substrate. The insulating substrate 38 is provided with the second conductive paths 39 and the second conductive lands 40 (which may be provided on the front surface but was intentionally written to show double-sided mounting), as in the metal substrate described above. 2 for the 2 conductive paths
A second semiconductor element such as a transistor is fixed to the component or the second semiconductor element on the second conductive land 40 via solder or the like. Of course, since it is double-sided mounting, the above-mentioned configuration electrically connects the circuits on both sides of the insulating substrate 38 through the through holes.

Here, the electrical contact between the circuits of the first substrate 30 and the second substrate 38 is the second bonding pad 41 provided on the periphery of the second substrate 38, and the first bonding pad 41 is provided corresponding to the position thereof. It is realized by the bonding pad 42 and the thin metal wire 43 connecting them. The feature of the present invention lies in the thin metal wire 43. In general, thin metal wires have plasticity and do not return once bent,
For example, a spacer is provided between the first substrate and the second substrate, the thin metal wire is bonded in the state where the spacer is provided, and after this spacer is removed, the thin metal wire achieves a state in which the second substrate is suspended. Further, after connecting the thin metal wire to the first bonding pad, it is bent downward from a higher position with a margin than the second substrate and connected to the second bonding pad. As a result, after bonding all, the second jig
By forcibly raising the substrate, it is possible to realize a hanging state with a predetermined interval.

The thin metal wire is generally 40 in the case of a signal wire.
About μmφ, thick one for large current is 200-500μ
If it is mφ and it is suspended with a small number of thin metal wires, dare to change it to a thick metal wire, or prepare an island-shaped bonding pad completely separated from the circuit like the metal wire indicated by L. If a thick pad is bonded to the pad, the second metal substrate 38 will not descend. In this case, although omitted in the drawing, at least two on the left and right
You can install the second substrate in a well-balanced manner if you have one at each of the four corners.

Further, as shown in FIG. 2, the lowering of the second substrate 38 is performed between the second substrate 38 and the first substrate 30, that is, the front surface of the first substrate or the back surface of the second substrate 38. It is possible to effectively utilize the semiconductor elements and parts fixed to the. That is, by providing an insulating means, such as an adhesive 44, on the upper surface of an element or component having a relatively high height, even if the second substrate descends, the insulating means 44 abuts and can function as a spacer without a short circuit. . Further, the spacer may be a semiconductor element or a component which is molded in advance. However, the upper surface of this element with which the second substrate 38 contacts must be an insulator. In this case, it is not necessary to separately provide a spacer for lowering the second substrate 38.

Finally, the leads are fixed, and although not shown in the drawing, they are housed in a box-shaped housing case or the like, and a resin is injected therein if necessary and sealed. In this case, a silicone-based or epoxy-based resin that does not cause gel-like distortion is preferable because it is injected between both substrates. Further, in FIG. 2, the second substrate is provided on the second substrate,
In this case, the size needs to be larger than that of the second substrate for the convenience of wire bonding. Therefore, if the upper substrates are arranged so that the size is larger, it is possible to stack virtually any number of them.

[0016]

As is apparent from the above description, the first
In addition, since the second substrate is hung by the thin metal wire, an adhesive for fixing the two substrates is not required between the first substrate and the second substrate, and warpage due to a difference in temperature coefficient between the substrates and The peeling can be eliminated. In addition, since there is no adhesive, it is possible to prevent deterioration of elements and parts between them, deterioration of the contact portion, deterioration of the contact portion of the metal fine wire, and the like. Further, since the two substrates are provided with a predetermined space, it is possible to mount a semiconductor element or a component having a certain height on the back surface of the second substrate, which can improve the packaging density. it can.

Next, when the bonding pad is provided separately from the circuit, for example, it is possible to prevent the substrate from descending when bonding with a thin metal wire. Furthermore, to prevent lowering, an insulating means is provided on the upper surface of the semiconductor element or component,
If the second substrate is brought into contact with the insulating means, the second substrate can be held at a constant interval without providing a separate spacer.

[Brief description of drawings]

FIG. 1 is a perspective view illustrating an embodiment of the present invention.

FIG. 2 is a cross-sectional view illustrating a laminated structure of the present application.

FIG. 3 is a plan view of a conventional multilayer hybrid integrated circuit device.

4 is a cross-sectional view of FIG.

[Explanation of symbols]

30 First substrate 31 Conductive path 32 Conductive land 35 Semiconductor element 37 parts 38 Second substrate 41 Second Bonding Pad 42 First Bonding Pad 43 thin metal wire

─────────────────────────────────────────────────── ─── Continuation of the front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) H01L 25/00-25/18 H05K 3/46

Claims (3)

(57) [Claims] 1. A hybrid integrated circuit device in which a plurality of substrates are stacked at a predetermined interval, the first conductive path being provided on at least one main surface, and electrically connected to the first conductive path. A first substrate on which a circuit is formed by the first semiconductor element and the first circuit component, and a first bonding pad is provided on the main surface thereof, and a main surface and a back surface of the first substrate are opposed to each other and are provided on at least the front surface. A second conductive path, a second semiconductor element electrically connected to the second conductive path, and a second circuit component form a circuit, and a second bonding pad corresponding to the first bonding pad is provided on the periphery. a second substrate, a metal thin wire is bonded between the first bonding pad and the second bonding pad, said second substrate at a predetermined interval on the first substrate is suspended by the thin metal wires Symptoms and the hybrid integrated circuit device. 2. The hybrid integrated circuit device according to claim 1, wherein the first bonding pad and / or the second bonding pad is electrically connected to a circuit. 3. A hybrid integrated circuit device in which a plurality of substrates are stacked at a predetermined interval, the first conductive path being provided on at least one main surface, and electrically connected to the first conductive path. A first substrate on which a circuit is formed by the first semiconductor element and the first circuit component, and a first bonding pad is provided on the main surface thereof, and a main surface and a back surface of the first substrate are opposed to each other and are provided on at least the front surface. A second conductive path, a second semiconductor element electrically connected to the second conductive path, and a second circuit component form a circuit, and a second bonding pad corresponding to the first bonding pad is provided on the periphery. A second substrate, and a thin metal wire is bonded between the first bonding pad and the second bonding pad. The thin metal wire hangs the second substrate on the first substrate at a predetermined interval,
The hybrid integrated circuit device, wherein the semiconductor element or the circuit component provided between the first substrate and the second substrate serves as a spacer between the two substrates by an insulating means provided on the upper portion.