JPS63299152A - Method of mounting semiconductor element - Google Patents

Abstract

PURPOSE:To attain a sufficient heat sink property without necessity of complicated steps and to perform mounting in a high density by forming in advance an indentation (a recess) in a predetermined region of a circuit substrate to be mounted and arranged with a predetermined semiconductor element, in the recess installing face to face a metal piece having substantially equal thermal expansion coefficient on that of the element to be mounted, and mounting the element on the face of the piece. CONSTITUTION:A first circuit substrate layer 1b having an inner layer wiring 1a is formed by using a green sheet, a hole for a position, region and conduction to mount a semiconductor element is opened thereon, a green sheet (second circuit substrate layer 1d) formed with h predetermined circuit pattern on its surface is laminated, integrally pressurized, and baked. A metal piece 9 having substantially equal thermal expansion coefficient as that of a transistor element, such as a Cu-W piece is mounted and arranged on a metallized layer in the recess of a circuit substrate 1 formed with the recess at the thus obtained predetermined region. Then, a transistor element 5' is mounted and arranged on the exposed face of the piece, i.e., the face of the piece formed substantially in the same plane as the face of the substrate.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Field of Application) The present invention relates to a method of mounting and arranging a semiconductor element on a wiring board, and particularly relates to a method of mounting a semiconductor element on a wiring board in consideration of heat dissipation. Regarding improvements.

(Prior art) Electronic components consisting of semiconductor elements such as integrated circuit elements (IC), transistor elements, field effect transistors (PET), and diode elements mounted on a wiring board (printed wiring board) are used for industrial purposes. It is widely used in the fields of electronic equipment and consumer electrical equipment.

However, the mounting of semiconductor elements on this type of wiring board,
Casting is attracting attention as a so-called high-density packaging technology.

By the way, in electronic components (S-product circuit components) formed by mounting the above-mentioned semiconductor elements, as the number of semiconductor elements to be mounted increases (higher density), how to dissipate the heat generated by these semiconductor elements becomes a problem. . In other words, the heat generated by the operation of the semiconductor elements and the like to be mounted has an adverse effect on the performance of those elements, so it is desired that the heat be dissipated as quickly as possible.

In response to these circumstances, in high-density packaging technology, conventional
A device having a configuration as shown in the figure is known. That is, a so-called seven-tooth sink 3 has a through hole selectively formed in the wiring board 1 according to the size of the semiconductor element to be mounted and disposed (flailed), and a protrusion 2 that engages with the through hole. This is a configuration that combines the following. In this case, the upper end surface of the protruding portion -2 of the heat sink 3 is substantially flat with the surface of the wiring board 1, and is integrated with the wiring board 1 by the adhesive layer 4. Thus, the semiconductor element 5 is insulatively mounted and arranged on the two surfaces of the protruding portion of the heat sink 3 that is engaged and integrated with the wiring board 1 (:, the input/output terminals are connected to the circuit pattern terminals 6 on the wiring board 1). It is electrically connected to the wire 7 by a wire 7.

However, in the above method, the electrical insulation between the mounted semiconductor element 5 and the heat sink 3 is insufficient, and the degree of insulation is adjusted depending on the type and capacity of the semiconductor element to be mounted (mounted). Complication is unavoidable, and in addition, in the case of this method, the heat sink 3 is connected to the wiring board 1.
The semiconductor element 5 cannot be mounted unless it is combined with the wiring board 1, and the wiring area of the wiring board 1 is also reduced due to the holes, so there is a limit to high-density mounting.

(Problems to be Solved by the Invention) Therefore, an object of the present invention is to provide a method for mounting semiconductor elements, which achieves sufficient heat dissipation without requiring complicated steps, and which also enables high-density mounting. do.

[Structure of the Invention] (Means for Solving the Problem) In the present invention, a recess (recess) is formed in advance in a predetermined area of a mounting board on which a required semiconductor element is to be mounted and arranged, and the recess is The main idea is to mount a metal piece having a coefficient of thermal expansion substantially equal to that of the element to be mounted inside the semiconductor device with its surface parallel to that of the element to be mounted, and to mount the semiconductor element on the surface of this metal piece.

(Function) According to the present invention, a metal piece is installed so as to be submerged in the area on the wiring board surface where the semiconductor element is to be mounted, and the semiconductor element is mounted on the upper surface (exposed surface) of this metal piece. In other words, one side (back side) remains a continuous wiring board surface,
selectively forming a gold 11L layer region on the other surface (front surface) side;
Required elements are mounted on the surface of this metal layer region and are electrically insulated from the heat sink. For this reason, there is no need to make special adjustments to the electrical insulation of each semiconductor element to be mounted, and since the metal piece is selected to have a coefficient of thermal expansion approximately equal to that of the element to be mounted, There is no fear of causing peeling or detachment of the element.

(Example) Hereinafter, an example in which a power transistor chip is mounted using an alumina ceramic substrate of the present invention will be described.

First, a first circuit board layer having inner layer wiring is made using a so-called green sheet, and then the position and area where the Azusa semiconductor element will be mounted and holes for conduction are cut out, and the required circuit pattern is formed on the surface of the green sheet. Sheet (
(referring to the second circuit board layer) were laminated and integrally pressed and fired. In this case, a metallized layer is previously formed on the exposed surface of the first circuit board layer, that is, on the portion corresponding to the hollowed out portion of the green layer laminated thereon.

A metal piece, such as a Cu-W type piece, having approximately the same thermal IIJwA rate as the transistor element is mounted and disposed on the metallized layer in the recess of the wiring board in which the recess is formed in the predetermined area thus obtained. After that, the exposed surface of the Cu-W-based piece disposed above, that is, the Cu-
Transistor elements are each mounted and arranged on the surface of the W-based piece.Next, the input/output terminals of the transistor elements mounted above are formed in advance on the surface of the wiring board, and electrical connections are made with circuit pattern terminals by soldering, for example, Ag111m. The required implementation is done by connecting the

FIG. 1 is a cross-sectional view of an integrated circuit component in which a heat sink is attached to the integrated circuit component in which a power transistor element is thus mounted. In FIG. 1, reference numeral 1 denotes a wiring board, which is composed of a first circuit board layer 1b having inner layer wiring 1a and a second circuit board jlld having a recessed IC. Further, 3 is a heat sink integrated with adhesive on the back side of the wiring board 1, 5a' is a power transistor element, 6 is a circuit pattern terminal on the front surface, 7 is an Ag thin wire, and 8 is a heat sink integrated with adhesive on the back side of the wiring board 1.
9 is a metallized layer provided on the first circuit board layer 1b, and 9 is a Cu layer mounted and arranged in the recess IC of the wiring board 1.
- A W-based metal piece, and 10 represent a conductor that electrically connects with the inner layer pattern 1a.

In the above description, since an example in which a power transistor element is mounted is described, the metal piece 9 mounted in the four parts 1c of the wiring board 1 is used as a connection conductor with the collector. An insulating layer may be formed on the mounting surface, and the wiring board 1 is not limited to the so-called multilayer wiring type having the inner wiring layer 1a as described above.Furthermore, the semiconductor elements to be mounted are not limited to power transistors. integrated circuit elements, FET elements, diode elements, combinations thereof, or other electronic components;
For example, there is no problem in combination with a capacitor, a resistor, etc.

[Effects of the Invention] As described above, according to the present invention, a region of a wiring board in which a semiconductor element is mounted is formed in a recess, a metal piece is mounted in this recess, and the element is mounted on this metal piece. . However, since each of the metal pieces is electrically insulated by an insulator that constitutes the main component of the wiring board, there is no risk of adverse electrical effects passing through other mounted semiconductor elements or attached heat sinks. That is, when mounting semiconductor elements, the required mounting can be performed without considering electrical insulation between the semiconductor elements to be mounted, or even when a heat sink is separately attached. Particularly when attaching a heat sink in consideration of improving heat dissipation, the ability to attach the heat sink after mounting the semiconductor element is effective as a mass-production mounting means. In this way, since the area where the semiconductor elements are mounted is a metal piece, it has good thermal conductivity, and the heat generated from the mounted elements is easily dissipated, and furthermore, a large area for circuit wiring can be secured on the wiring board. Combined with the ease of high-density mounting, this can be said to bring many practical advantages.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing an example of an integrated circuit component constructed by mounting semiconductor elements by the method of the present invention, and FIG. 2 is a sectional view showing an example of an integrated circuit component constructed by conventional mounting means. 1...Wiring board 1d...Recessed portion 5'...Transistor element (semiconductor element) 6.
......Circuit pattern terminal 9...
・Cu-W type piece (metal piece) Applicant Toshiba Corporation Representative Patent Attorney Sasu Suyama - Figure 2

Claims (1)

[Claims] A metal piece having approximately the same coefficient of thermal expansion as a semiconductor element to be mounted is mounted in the recess of a wiring board having a predetermined circuit pattern and recesses selectively formed in the thickness direction. a step of mounting and arranging a semiconductor element on the exposed surface of the mounted metal piece; and a step of electrically connecting input/output terminals of the mounted semiconductor element to predetermined circuit pattern terminals. A method for mounting a semiconductor device, comprising: