JPH04335542A - Electrode for semiconductor device and mounted body - Google Patents

Abstract

PURPOSE:To provide a mounted body and an electrode for a semiconductor device in which the device can be easily connected to a circuit board with high reliability. CONSTITUTION:A bump electrode 3 having two-stage protrusion shape of a pedestal part and a top part, is provided on an aluminum electrode pad 2 of an IC board 1 of a semiconductor device, an electrode structure in which a solder bonding layer 4 is formed on the top part of the electrode 3, is provided, and a mounting structure in which the device is electrically connected to a terminal electrode 7 on a circuit board 6 through the layer 4, is provided. An extension of the solder bonding layer can be controlled by the electrode 3 having the two-stage protrusion shape, and bonding at a fine pitch can be realized.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrode structure for mounting a semiconductor device on a circuit board, and more particularly to an electrode and a mounting body for a semiconductor device mounted face-down.

0002

[Prior Art] In the past, soldering was often used to mount semiconductor devices on circuit boards, but in recent years, as semiconductor device packages have become smaller and the number of connection terminals has increased, the spacing between connection terminals has become narrower. It has become increasingly difficult to deal with this problem using conventional soldering techniques.

[0003]Recently, therefore, a method has been devised in which a bare semiconductor device is directly attached to a circuit board in order to reduce the mounting area and to achieve efficient use.

In particular, when connecting a semiconductor device to a circuit board, an electrode structure consisting of a vapor-deposited film of an adhesive metal or a diffusion-preventing metal and a solder layer formed by plating on the aluminum electrode pad of the semiconductor device is prepared in advance. The mounting structure, in which the semiconductor device is placed face down and heated to a high temperature to fuse the solder to the terminal electrodes of the circuit board, is effective because it has strong mechanical strength after connection and can be connected all at once. It is said to be a method. (For example, Kogyo Kenkyukai, January 15, 1980, edited by Japan Microelectronics Association, "IC Mounting Technology") Below is an example of the electrode structure and mounting structure of the conventional semiconductor device mentioned above, with reference to the drawings. explain.

FIG. 3 is a schematic explanatory diagram of the electrode structure of a semiconductor device having conventional solder bump electrodes, and FIG. 4 is a schematic explanatory diagram of the mounting structure of the semiconductor device.

In (FIG. 3), 8 is an IC of a semiconductor device.
It is a substrate, and 9 is an aluminum electrode pad. 10 is an adhesive metal film, and 11 is a diffusion prevention metal film. 12 is a solder protrusion, and 13 is a passivation film. In (FIG. 4), 14 is a circuit board, and 15 is a terminal electrode.

An outline of the electrode structure and mounting structure of a semiconductor device having a conventional solder bump electrode constructed as described above will be explained below.

First, an adhesion metal film 10 such as Cu and a diffusion prevention metal film 11 such as Cr are formed by vapor deposition on the aluminum electrode pad 9 of the IC substrate 8 of the semiconductor device. Thereafter, parts other than the electrode part are covered with photoresist, and solder is deposited on the diffusion prevention metal film 11 by a plating method, and solder reflow is performed to form solder protrusions 12 to obtain the solder bump electrode (FIG. 3). .

Furthermore, after aligning the semiconductor device having the solder bump electrodes obtained as described above to a predetermined position on the circuit board 14 and loading it face down,
The semiconductor device is mounted by heating to a high temperature of 00 to 300° C. to melt the solder projections 12 and fuse them to the terminal electrodes 15.

0010

[Problems to be Solved by the Invention] However, in the electrode structure and mounting structure of a semiconductor device having solder bump electrodes as described above, 1. An adhesive metal film or a diffusion prevention metal film is required on the aluminum electrode pad of a semiconductor device, making the electrode structure complicated and lacking in versatility.

2. When heating the IC board to a high temperature to melt the solder and connect it to the terminal electrode, it is not possible to maintain a gap between the IC board and the circuit board, so there is a risk that the solder will spread and cause a short circuit with the adjacent circuit board. There were issues such as these.

The present invention has been made in view of the above-mentioned problems, and its object is to provide an electrode structure and a mounting structure for a semiconductor device that can easily and reliably connect the semiconductor device and a circuit board. Our goal is to provide the following.

[0013]

[Means for Solving the Problems] In order to solve the above-mentioned problems, the present invention provides, in a semiconductor device mounted face-down on a circuit board, a two-stage protrusion of a pedestal portion and a top portion on an aluminum electrode pad portion of the semiconductor device. The bump electrode has an electrode structure in which an inorganic bonding layer is formed only on the top of the two-step protruding bump electrode, and the two-step protruding bump electrode is on an aluminum electrode pad portion of a semiconductor device. The present invention is characterized by having a mounting structure in which a semiconductor device is electrically connected to a terminal electrode on a circuit board via an inorganic bonding layer, and is intended to realize highly reliable mounting of a semiconductor device on a circuit board.

[0014]

[Operation] The present invention has an electrode structure in which an inorganic bonding layer is formed only on the top of a two-step protrusion-shaped bump electrode formed directly on an aluminum electrode pad portion of a semiconductor device.
When a semiconductor device is bonded to a terminal electrode of a circuit board, the bonding layer can be bonded at a fine pitch without shorting with the adjacent layer, and a highly reliable semiconductor device mounting structure can be realized.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An electrode for a semiconductor device and a mounting body according to an embodiment of the present invention will be described below with reference to the drawings.

(FIG. 1) is a schematic explanatory diagram of the electrode structure of a semiconductor device in one embodiment of the present invention, and (FIG. 2) is a
FIG. 2 is a schematic explanatory diagram of a mounting structure of a semiconductor device having the electrode structure of the above embodiment.

In (FIG. 1), 1 is an IC of a semiconductor device.
It is a substrate, and 2 is an aluminum electrode pad. Reference numeral 3 denotes a two-step protruding bump electrode consisting of a base portion and a top portion, and numeral 4 represents a solder bonding layer formed only on the top portion of the two-step protruding bump electrode. 5 is a passivation film. (Figure 2
), 6 is a circuit board, and 7 is a terminal electrode.

The electrode structure and mounting structure of the semiconductor device constructed as above will be explained below with reference to the drawings.

First, an Au ball at the tip of an Au wire is fixed onto an aluminum electrode pad 2 of an IC substrate 1 of a semiconductor device in the same manner as in a normal wire bonding technique, and then the pedestal portion and top portion are separated by cutting the Au wire. A bump electrode 3 having a two-stage protrusion shape is formed.

[0020] Thereafter, a solder bonding layer 4 is formed only on the top portion of the two-step protruding bump electrode 3 by a transfer method or a printing method. At this time, solder reflow is performed if necessary.

As described above, an electrode structure consisting of a two-step protruding bump electrode 3 and a solder bonding layer 4 can be easily obtained on an aluminum electrode pad 2 of a general-purpose semiconductor device.

In the electrode structure of the semiconductor device of the present invention, a bump electrode having a two-stage protrusion can be obtained using a normal wire bonding device by the method described above. It can be used and is extremely versatile.

Furthermore, after aligning the semiconductor device having the electrode structure obtained as described above to a predetermined position on the circuit board 6 and mounting it face down,
The semiconductor device is mounted by heating to a high temperature of 00° C. to melt the solder bonding layer 4 and fusing it to the terminal electrode 7.

When heating to this high temperature to melt the solder bonding layer 4 and connect it to the terminal electrode 7, the IC board 1 and the circuit board 6
The gap can be maintained by the two-step protruding bump electrode 3, and the solder bonding layer 4 can be formed only at the top, making it possible to restrict the spread of solder. There is no risk of short-circuiting with the adjacent
A semiconductor device mounting structure that allows connection at a fine pitch can be obtained.

[0025] In the semiconductor device mounting structure of the present invention, by using the above-described method, it is possible to control the spread of solder, which was impossible with the conventional mounting structure using solder bump electrodes, by using the two-step protruding bump electrodes. Therefore, semiconductor devices can be mounted extremely stably and reliably with high density.

In this embodiment, the two-step protruding bump electrode is formed using a wire bonding device, but as long as the bump electrode has a two-step protruding shape, it may be formed by other methods such as plating.

Furthermore, although the bump electrode is made of Au, the material is not limited to Au; for example, C
It may be formed from other metals such as u.

Furthermore, the solder bonding layer formed on the top of the two-stage bump electrode may be formed by transferring or printing a solder paste.

[0029]

Effects of the Invention As explained above, according to the electrode for a semiconductor device and the mounting body of the present invention, it can be formed directly on the aluminum electrode pad portion of a semiconductor device using a normal wire bonding machine, so that it can be used for general purpose use. This makes it possible to use several semiconductor devices, making it extremely versatile.

Furthermore, by having an electrode structure in which an inorganic bonding layer is formed only on the top of the bump electrode in the shape of a two-step protrusion, it is possible to control the spread of the inorganic bonding layer when bonding a semiconductor device to a terminal electrode of a circuit board. This makes it possible to create a mounting structure in which the inorganic bonding layer can be bonded at a fine pitch without shorting with the adjacent layer, making it possible to mount semiconductor devices extremely stably, reliably, and with high density.

[Brief explanation of drawings]

FIG. 1 is a schematic explanatory diagram of an electrode of a semiconductor device in an embodiment of the present invention.

FIG. 2 is a schematic explanatory diagram of a semiconductor device package having an electrode structure according to an embodiment of the present invention.

FIG. 3 is a schematic explanatory diagram of an electrode of a semiconductor device having a conventional solder bump electrode.

FIG. 4 is a schematic explanatory diagram of a semiconductor device package having conventional solder bump electrodes.

[Explanation of symbols]

1 IC substrate for semiconductor devices 2 Aluminum electrode pad 3. Two-step protruding bump electrode 4 Solder joint layer 5 Passivation film 6 Circuit board 7 Terminal electrode 8 IC substrate of semiconductor device 9 Aluminum electrode pad 10 Adhesive metal film 11 Diffusion prevention metal film 12 Solder protrusion 13 Passivation film 14 Circuit board 15 Terminal electrode

Claims (8)

[Claims] 1. An electrode for a semiconductor device that is mounted face-down on a circuit board, comprising a two-step protruding bump electrode having a pedestal portion and a top portion on an aluminum electrode pad portion of the semiconductor device; An electrode for a semiconductor device, characterized in that an inorganic bonding layer is formed only on the top of a bump electrode. 2. The electrode for a semiconductor device according to claim 1, wherein the two-step protruding bump electrode is made of Au. 3. The electrode structure for a semiconductor device according to claim 1, wherein the two-step protruding bump electrode is formed of Au wire using a wire bonding device. 4. The electrode for a semiconductor device according to claim 1, wherein the inorganic bonding layer is made of solder. 5. In a semiconductor device mounting body that is mounted face-down on a circuit board, a two-step protruding bump electrode on an aluminum electrode pad portion of the semiconductor device is connected to a terminal electrode on the circuit board via an inorganic bonding layer. A mounting body for a semiconductor device characterized by electrical connection. 6. The semiconductor device mounting body according to claim 5, wherein the two-step protruding bump electrode is made of Au. 7. The semiconductor device mounting body according to claim 5, wherein the two-step protruding bump electrode is formed of Au wire using a wire bonding device. 8. The semiconductor device mounting body according to claim 5, wherein the inorganic bonding layer is made of solder.