JP2633745B2 - Semiconductor device package - Google Patents

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 a semiconductor device electrode and a mounting body mounted face-down.

[0002]

2. Description of the Related Art Conventionally, soldering has often been used for mounting a semiconductor device on a circuit board. However, in recent years, the spacing between connection terminals has been reduced due to the miniaturization of the package of the semiconductor device and the increase in the number of connection terminals. It has become increasingly difficult to deal with the conventional soldering technology.

Therefore, recently, a method has been devised in which a bare semiconductor device is directly mounted on a circuit board in order to reduce the mounting area and use the device efficiently.

In particular, when connecting a semiconductor device to a circuit board, an electrode structure composed of a deposited film of an adhesion metal or a diffusion preventing metal on an aluminum electrode pad of the semiconductor device in advance and a solder layer formed thereon by plating is used. A mounting structure in which the semiconductor device is turned downward (face down) and heated to a high temperature to fuse the solder to the terminal electrodes of the circuit board is effective because the mechanical strength after connection is strong and the connection can be made at once. It is said to be the way. (For example, Industrial Research Council, published on January 15, 1980, edited by the Japan Microelectronics Association, "IC mounting technology") An example of the above-described electrode structure and mounting structure of the conventional semiconductor device will be described with reference to the drawings. explain.

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

In FIG. 3, reference numeral 8 denotes an IC of a semiconductor device.
A substrate 9 is an aluminum electrode pad. Reference numeral 10 denotes an adhesion metal film, and reference numeral 11 denotes a diffusion prevention metal film. Reference numeral 12 denotes a solder protrusion, and reference numeral 13 denotes a passivation film. In FIG. 4, 14 is a circuit board, and 15 is a terminal electrode.

[0007] The electrode structure and mounting structure of a conventional semiconductor device having a solder bump electrode configured as described above will be outlined below.

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

Further, the semiconductor device having the solder bump electrodes obtained as described above is aligned face-to-face with a predetermined position on the circuit board 14, and is loaded face-down.
The semiconductor device is mounted by heating to a high temperature of 00 to 300 ° C. to melt the solder protrusions 12 and fuse them to the terminal electrodes 15.

[0010]

However, in the electrode structure and mounting structure of a semiconductor device having the above-mentioned solder bump electrodes, there are the following problems. The adhesion metal film and the diffusion prevention metal film are required on the aluminum electrode pad of the semiconductor device, which complicates the electrode structure and lacks versatility.

2. When heating to a high temperature to melt the solder and connect it to the terminal electrodes, it is not possible to maintain the gap between the IC substrate and the circuit board. And so on.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has as its object to provide an electrode structure and a mounting structure of a semiconductor device which can easily and reliably connect the semiconductor device and a circuit board. Is to provide.

[0013]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a semiconductor device mounted face down on a circuit board. Having an electrode structure in which an inorganic bonding layer is formed only on the top of the above-mentioned two-stage bump electrode, and a two-stage bump electrode on an aluminum electrode pad portion of a semiconductor device. Has a mounting structure for electrically connecting the semiconductor device to a terminal electrode on a circuit board via an inorganic bonding layer, thereby realizing mounting of a highly reliable semiconductor device on the circuit board.

[0014]

The present invention has an electrode structure in which an inorganic bonding layer is formed only on the top of a two-step projection-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, bonding can be performed at a fine pitch without a short circuit between adjacent bonding layers, and a highly reliable semiconductor device mounting structure can be realized.

[0015]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an exploded perspective view of a semiconductor device according to an embodiment of the present invention;

FIG. 1 is a schematic explanatory view of an electrode structure of a semiconductor device according to one embodiment of the present invention, and FIG.
FIG. 3 is a schematic explanatory view of a mounting structure of the semiconductor device having the electrode structure of the embodiment.

In FIG. 1, reference numeral 1 denotes an IC of a semiconductor device.
A substrate 2 is an aluminum electrode pad. Numeral 3 denotes a bump electrode having a two-stage protrusion composed of a pedestal portion and a top portion, and numeral 4 denotes a solder bonding layer formed only on the top portion of the bump electrode having a two-stage protrusion shape. 5 is a passivation film. In FIG. 2, 6 is a circuit board, and 7 is a terminal electrode.

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

First, an Au ball at the tip of an Au wire is fixed on 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 Au wire is cut to obtain a pedestal portion and a top portion. To form a bump electrode 3 having a two-step protrusion shape.

Thereafter, the solder bonding layer 4 is formed only on the top of the bump electrode 3 having a two-step projection by a transfer method or a printing method. At this time, solder reflow is performed as needed.

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

According to the electrode structure of the semiconductor device of the present invention, a bump electrode having a two-step projection can be obtained by a normal wire bonding apparatus by the above-described method. It can be used and is extremely versatile.

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

When the soldering layer 4 is melted by heating to a high temperature and connected to the terminal electrodes 7, the IC board 1 and the circuit board 6
Can be maintained by the bump electrode 3 having a two-step projection, and the solder bonding layer 4 can be formed only on the top, so that the spread of solder can be restricted. There is no danger of short circuit with the neighbor,
A mounting structure of a semiconductor device which can be connected at a fine pitch is obtained.

According to the mounting structure of the semiconductor device of the present invention, the spread of the solder, which was impossible with the conventional mounting structure using the solder bump electrodes, can be controlled by using the bump electrodes having a two-step projection. Thus, the semiconductor device can be mounted very stably, with high reliability and with high density.

In the present embodiment, the bump electrode having a two-step projection is formed by using a wire bonding apparatus. However, if the shape of the bump electrode is a two-step projection, it may be formed by another method such as plating.

Although the bump electrode is made of Au, the material is not limited to Au.
It may be formed from other metals such as u.

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

[0029]

As described above, according to the semiconductor device electrode and the package of the present invention, since it can be formed directly on the aluminum electrode pad portion of the semiconductor device by a normal wire bonding apparatus, it can be used for general purpose. Semiconductor device can be used, and the versatility is extremely high.

Further, by having an electrode structure in which the inorganic bonding layer is formed only on the top of the bump electrode having a two-step projection, the spread of the inorganic bonding layer when the semiconductor device is bonded to the terminal electrode of the circuit board is restricted. This makes it possible to achieve a mounting structure that enables bonding at a fine pitch without short-circuiting the inorganic bonding layer to the adjacent layer, and enables extremely stable, highly reliable, and high-density mounting of the semiconductor device.

[Brief description of the drawings]

FIG. 1 is a schematic explanatory view of an electrode of a semiconductor device according to an embodiment of the present invention.

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

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

FIG. 4 is a schematic explanatory view of a conventional mounting body of a semiconductor device having solder bump electrodes.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 IC substrate of semiconductor device 2 aluminum electrode pad 3 two-step protruding bump electrode 4 solder bonding layer 5 passivation film 6 circuit board 7 terminal electrode 8 IC substrate of semiconductor device 9 aluminum electrode pad 10 adhesion metal film 11 diffusion preventing metal film 12 solder protrusion 13 passivation film 14 circuit board 15 terminal electrode

Claims (2)

(57) [Claims] 1. A semiconductor device having a structure in which a semiconductor device is mounted face-down on a terminal electrode portion on a substrate, and wire bonding is performed on an electrode pad portion of the semiconductor device.
A first protrusion directly formed by a method and a first protrusion formed on the first protrusion and having a cross-sectional area smaller than a cross-sectional area of the first protrusion parallel to the electrode pad. A bump electrode made of a two-step protrusion made of Au having a second protrusion having a cross-sectional area, and the terminal electrode portion on the substrate are electrically connected via a solder bonding layer; The semiconductor device package according to claim 1, wherein the solder bonding layer is formed only on the bump electrode having a two-step protrusion shape centering on the first protrusion. 2. An electrode structure comprising a first protrusion, a second protrusion, and a solder bonding layer, wherein the first and second protrusions are wire bonding.
The second protrusion is formed on the first protrusion by a cross-sectional area of a horizontal plane smaller than that of the first protrusion, and the second protrusion is formed on the first protrusion. Thus, a bump electrode made of Au having a two-step protrusion is formed, and the solder bonding layer is formed only on the bump electrode having a two-step protrusion centering on the first protrusion. Electrode structure.