JPS63250164A - High power hybrid integrated circuit substrate and its integrated circuit - Google Patents

Abstract

PURPOSE:To stabilize quality with no current concentration and to decrease width of copper circuit patterns and to miniaturize the whole of circuits, by standardizing thickness of the whole of copper circuit patterns to be 35 mum or more. CONSTITUTION:Thick copper foil parts 1 as lower layers composed of heterogeneous metal composite foils are laminated on a base metal 6 through an insulating layer 5, and also aluminium bonding posts 3 as upper layers are laminated thereon. Power transistors 7 and diodes 8 are connected with the aluminium bonding posts 3 by the use of aluminium wires 9 so as to form circuits. Thickness of each copper foil thick part of the heterogeneous metal composite foils used in this invention is required to be 35mum or more, and large current conduction capacity can not be obtained when this thickness is 35mum or less. Though an upper limit is not restricted, this limit is 300mum or so in consideration of cost. Then, for example, silicon resin can be singly used or filler-containing silicon resin of good heat conductivity can be used as gelled silicon group resin which seals the circuits.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Field of Application) The present invention is designed to make all of the copper circuit patterns have a wall thickness exceeding 65 μm so that they can be used as circuit parts that require large currents.

- relates to hybrid integrated circuits for

(Prior technology) Ceramic substrates have traditionally been widely used as hybrid integrated circuit boards for power modules, but because the circuits are formed using noble metal paste, their sheet resistance is large, and the current trend in power modules has increased in recent years. It is becoming unsuitable for Therefore, in the past, all circuits were soldered to thin metal plates such as copper to cope with the increased current. In addition, as an alternative board, a metal base board was developed that had a circuit with exposed metals of both aluminum and copper and used a highly thermally conductive resin for the insulating layer (Japanese Patent Laid-Open No. 58-48432). Public bulletin)
.

This board uses a part of the circuit with exposed copper to form a circuit by soldering, such as connecting a heat spreader or an external board, and a part of the circuit with exposed aluminum to perform ultrasonic vibration aluminum wire bonding with a semiconductor bare chip. It is designed to do the following.

However, in this method, the current value is limited due to the thin thickness of the metal foil, and it is impossible to solder the heating element directly to the copper foil because the copper foil is thin, and a heat spreader is required.

There are also high-power hybrid integrated circuits in which large current carrying circuits, semiconductors, and heat generating elements are provided by applying thick plating to the exposed areas of the aluminum and copper circuit patterns. 62-2587).

On the other hand, in copper circuits where thick plating is applied locally, the bonding metal foil between aluminum and copper, which cannot be plated thickly, is too thin; Due to the limited current value and the long plating time, there was a drawback that the quality of the high-power hybrid integrated circuit lacked stability.

(Problems to be Solved by the Invention) The present invention solves these drawbacks by stabilizing the quality of the copper power hybrid integrated circuit and further reducing the width of the copper circuit pattern. Can be made smaller. Furthermore, we have completed a high-power hybrid integrated circuit that simplifies the circuit fabrication process and reduces manufacturing costs.

(Means for Solving the Problems) That is, the present invention provides: 1) A high-power hybrid integrated circuit characterized by having a wall thickness of 65 μm (RAM circuits, etc.) connected to the base metal via an insulating layer with aluminum wires. A semiconductor device is mounted on a substrate, an external lead terminal is connected to a circuit board in which the semiconductor and an aluminum circuit are connected with an aluminum wire, and the circuit board is coated with a delta-shaped silicon resin and epoxy resin composition. This is a bi-power hybrid integrated circuit characterized by being sealed with

The present invention will be explained in detail below.

FIG. 1 (aL (t+)) is a plan view and a cross-sectional view of an embodiment showing a hybrid integrated circuit of the present invention.A lower layer made of dissimilar metal bonding foil is formed on the base metal 6 with an insulating layer 5 interposed therebetween. Thick copper foil part 1, upper layer is aluminum bonding post 3
are laminated. In addition, a semiconductor such as a power transistor 7 is placed locally on the thick copper foil portion 1 using eutectic solder 10 for large current, and other heat sensing elements such as a transistor, FET, IC, etc. Specifically, a diode 8 is installed. Furthermore, these power transistors 7 and diodes 8 are connected to aluminum bonding posts 3 by aluminum wires 9 to form a circuit. Next, in FIG. 2, after connecting the external lead terminal 11 at the external lead terminal soldering part 4 of the circuit shown in FIG.
FIG. 2 is a cross-sectional view of a circuit whose upper layer is sealed up to the upper end of the package 12 with a ripple-shaped silicone resin 13 and an epoxy resin composition 14.

The base metal plate used in the present invention may be made of aluminum, copper, iron, or an alloy thereof, which has good thermal conductivity.
Ru. Insulating layers with good thermal conductivity include alumina, beryllia,
Thermosetting resins containing, for example, 60% by weight or more of inorganic fillers with good thermal conductivity such as boron nitride, magnesia, silicane, and aluminum nitride, etc., are preferably thin as long as the withstand voltage is acceptable. It is necessary to have a thickness of 20 μm or more.

According to the present invention, there are two methods for forming a circuit in which both the aluminum and thick copper foil of the dissimilar metal bonding foil are exposed; one is aluminum-copper clad foil or copper plating on aluminum foil. Aluminum foil with zinc or copper through nickel? A circuit is formed by etching a substrate in which sequentially plated foils are laminated onto an insulator.

Further, the thickness of the exposed copper foil portion of the dissimilar metal main layer gold foil used in the present invention is more than 65 μm, preferably 45 μm to 600 μm.
1 More preferably, it is 50 μm to 150 μm. If the wall thickness is 65 μm or less, a large current carrying capacity cannot be obtained, and although there is no particular upper limit, the limit is about 30 μm in terms of cost.

Next, the shell-shaped silicone resin that stops the circuit is, for example,
Either a silicone resin alone or a filler-containing silicone resin having good thermal conductivity may be used. Furthermore, epoxy position 1
The fat composition is not limited in any way as long as it is moisture resistant and has low stress.

In other words, the substrate used in the hybrid integrated circuit of the present invention is a circuit board in which both aluminum and thick copper foil metals are exposed.
Since circuit #5 made of thick copper foil is also present under the exposed aluminum circuit, it has sufficient current capacity and a large current can flow through it. Furthermore, since the portion to which the heating element is completely fixed is also made of thick copper foil, it also serves as a heat spreader if the heating element is completely soldered.

In other cases, the heat generation of the heating element (power element) = 1, the size, and the thermal conductivity of the substrate are issues.Therefore, a metal substrate with a heat conduction layer with good heat conduction properties is used for high power hybrid integration according to the present invention. Necessary as a circuit.

(Example) This will be explained in detail below using examples.

Embodiment As shown in FIG. 4 (b), the substrate is made of a 120 μm thick copper foil and a 10 μm thick copper foil on a base metal plate 6 with an insulating layer 5 interposed therebetween.
It is composed of dissimilar metals consisting of aluminum foil and gold foil. First of all, on this board, the solder paste was used to be solder paste on the necessary parts (terminal mounting portion, powertresse rangster and diode mounting portion]. and 1.
Six diodes of 5 x 1.5 x 0.29 were placed at the locations shown in Figure 1 and soldered through a solder reflow oven.

Next, using a thick aluminum wire having a diameter of 400 μm, wire bonding was performed from this power transistor to an aluminum bonding post using an ultrasonic vibration method.・Wire bonding was done to the power transistor and diode of the same machine.

Next, after soldering the 14 external lead terminals with gold, the package was placed over the circuit, and silicone resin was injected until it covered the aluminum wires and power transistors as shown in Figure 2, and was cured into a gel-like state.

Thereafter, an epoxy resin composition was injected from the positive and negative sides and cured.

By going through the above steps, a high-power power module (inverter) for controlling a motor was completed, having the electric circuit shown in FIG. This inverter is collector insulated, so it is easy to install and has a total allowable current of 4OA.

(Comparative example) Is the pond in Figure 4 with a copper foil of 10 μm the same board as the example? Using this method, the inverter shown in Fig. 3 was constructed.

First, the same power transistor as in the example, 16×16
It was soldered to a x0.8JJI copper heat spreader using high temperature solder. This product was placed on a screen-printed board with solder paste in the same manner as in all Examples, and soldered together with the diode by complete solder reflow.

Is the subsequent process the same machine as the example and a pan-packed finished product? ,Obtained. Since the copper foil thickness of this inverter was as thin as 10 μm, the allowable current was 10 A or less.

(Effects of the Invention) As described above, the present invention is a circuit in which a semiconductor or the like and an aluminum circuit are connected by an aluminum wire in an insulated metal substrate having an aluminum circuit pattern partially on a thick copper circuit pattern. (1) There is no need to reinforce the circuit with a thin metal plate on the ceramic substrate to allow the current to flow through it. (2) There is no need to fully solder the heat spreader, and (3) there is no need for aluminum wire bonding posts, so the aluminum wire wire bonding of semiconductors can be done with high reliability. Especially several hundred μ
Thick aluminum wire with a diameter of m is indispensable for stuffing semiconductor devices such as power transistors that carry large currents, and this thick aluminum wire has the advantage of being wire bondable.

Furthermore, by using a metal substrate having an insulating layer with good thermal conductivity, (4) the thermal conductivity is better than in the case of using a conventional ceramic substrate, which is advantageous for increasing the power of the power module. Moreover, (5) in a power module using a ceramic substrate, since the ceramic is easily broken, a paste metal such as a nickel-plated copper plate must be bonded to the ceramic substrate by soldering, etc., but with a metal substrate, the paste metal is Since it is placed at the bottom of the package as shown in the figure, it has the advantage that there is no need to place new paste metal.

[Brief explanation of drawings]

1(a) and (1)) are a plan view and a sectional view of a high power hybrid integrated circuit of the present invention, and FIG. 2 is a sectional view of an integrated circuit in which the integrated circuit of FIG. 1 is suppressed. represents. FIG. 3 is an electrical circuit diagram. Next, Fig. 4(a), (1
)) is a plan view and a cross-sectional view showing the board before mounting. Code 1... Thick copper foil part, 3... Aluminum bonding post, 4... External lead terminal soldering part, 5...
- Insulating layer, 6... Base metal plate, 7... Power transistor, 8... Diode, 9... Aluminum wire, 10... Eutectic solder, 11... External lead terminal, 12 ... Package, 13-... R-shaped silicone resin, 14... Epoxy resin composition

Claims (3)

[Claims] (1) A semiconductor is placed on a substrate on which a copper circuit pattern with a thickness exceeding 35 μm and an aluminum circuit pattern formed on the circuit are provided on a base metal via an insulating layer, and the semiconductor and the aluminum circuit are connected to each other. A high-power hybrid integrated circuit board characterized by connecting the two with aluminum wires. (2) The integrated circuit according to claim 1, wherein the insulating layer is made of a resin composition with good thermal conductivity. (3) A semiconductor is placed on a substrate on which a copper circuit pattern with a thickness exceeding 55 μm and an aluminum circuit pattern formed on the circuit are provided on a base metal via an insulating layer, and the semiconductor and the aluminum circuit are connected to each other. 1. A high-power hybrid integrated circuit, characterized in that an external lead terminal is connected to a circuit board which is connected with an aluminum wire, and the circuit board is sealed with a gel-like silicon resin and an epoxy resin composition.