JP3119739B2 - Method for forming electrode for semiconductor device and 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 of a semiconductor device when the semiconductor device is mounted on a circuit board, a method of forming the same, and a mounting body, and more particularly to an electrode structure of a semiconductor device mounted face-down. And a method for forming the same and a package.

[0002]

2. Description of the Related Art Conventionally, soldering has often been used to mount a semiconductor device on a circuit board.
As the package of the semiconductor device has become smaller and the number of connection terminals has increased, the interval between the connection terminals has become narrower, and it has become increasingly difficult to deal with the conventional soldering technology.

Therefore, recently, a method has been devised in which a semiconductor device is directly mounted on a circuit board to reduce the mounting area, and the circuit board is used efficiently. Above all, when connecting a semiconductor device to a circuit board, a semiconductor having an electrode structure in which a vapor deposition film of an adhesion metal or a diffusion preventing metal is formed in advance on an aluminum electrode pad, and a solder layer is formed thereon by plating. The device is manufactured, this semiconductor device is mounted face down on a circuit board and heated to a high temperature to fuse the solder and the terminal electrodes of the circuit board. This method is considered to be an effective method because it can be connected to the Internet (for example, the Industrial Research Council, published on January 15, 1980, edited by the Japan Microelectronics Association, "IC mounting technology").

An example of a conventional electrode structure of a semiconductor device, a method of forming the same, and an example of a package will be described below with reference to the drawings. FIG. 4 is a schematic explanatory view showing a conventional method for forming an electrode for a semiconductor device having solder bump electrodes, FIG. 5 is a schematic explanatory view showing an electrode structure, and FIG. 6 is a schematic explanatory view showing a mounted body.

In FIGS. 4 and 5, reference numeral 10 denotes an IC substrate of a semiconductor device, 11 denotes an electrode pad, 12 denotes a passivation film, 13 denotes an adhesion metal film, 14 denotes a diffusion preventing metal film, 1
Reference numeral 5 denotes a photoresist film. Reference numeral 16 denotes a solder bump after plating, and reference numeral 17 denotes a solder bump after reflow. In FIG. 6, reference numeral 18 denotes a circuit board, and 19 denotes a terminal electrode.

An outline of an electrode structure of a conventional semiconductor device having such a component and having a solder bump electrode, a method of forming the same, and a package will be described below.
First, as shown in FIG.
An adhesion metal film 13 such as Cu and a diffusion prevention metal film 14 such as Cr are formed on the 0 electrode pad 11 by vapor deposition. Thereafter, as shown in FIG. 4B, the portions other than the electrode portions are covered with a photoresist 15, and the solder is deposited on the diffusion preventing metal film 14 by a plating method, and the mushroom-shaped solder bumps 16 shown in FIG. obtain. Finally, by performing solder reflow, solder bumps 17 are formed as shown in FIG. 4D to obtain solder bump electrodes having the electrode structure of FIG.

Further, the semiconductor device having the solder bump electrodes obtained in this manner is positioned face to face at a predetermined position on the circuit board 18, and then mounted on the circuit board 18.
By heating to a high temperature of 0 to 300 ° C. to melt the solder bumps 17 and fuse them to the terminal electrodes 19, a semiconductor device package as shown in FIG. 6 can be obtained.

[0008]

However, an electrode structure of a semiconductor device having the above-mentioned solder bump electrode, a method of forming the same, and a package are as follows. When heating to a high temperature to melt the solder and connect it to the terminal electrodes, the gap between the IC board and the circuit board cannot be maintained, and therefore, there is a risk that the solder spreads and short-circuits with an adjacent part. Since the IC board and the circuit board having different thermal expansions are connected by solder, they have a problem that they are brittle against thermal stress.

The present invention has been made in view of the above problems, and provides an electrode structure of a semiconductor device, a method of forming the electrode structure, and a mounting body that can easily and highly reliably connect the semiconductor device and a circuit board. The purpose is to do so.

[0010]

According to a first aspect of the present invention, there is provided:
The semiconductor device package is mounted face down on the circuit board.
A package of a semiconductor device to be mounted.
A projection with an uneven surface at the tip formed on the pole pad
The electrodes are connected to the terminal electrodes on the circuit board via conductive adhesive.
It is characterized by being electrically connected. The present invention
The package of the semiconductor device according to claim 2 is the package according to claim 1.
The projection electrode is made of Au. The present invention
4. The method for forming an electrode for a semiconductor device according to claim 3, wherein
Forming electrodes for semiconductor devices mounted on circuit boards by down
The method comprises the steps of: forming a projection on an electrode pad portion of a semiconductor device;
Forming an electromotive electrode, and forming the bump electrodes on the surface with irregularities.
Pressing the formed flat base; and
By vibrating with sound waves, a concave
Forming a convex surface . Departure
The method for forming an electrode for a semiconductor device according to claim 4 is
In claim 3, the protruding electrode is plated by Au.
It is characterized by being formed . Claim 5 of the present invention
The method for forming an electrode for a semiconductor device according to claim 3, wherein
Electrode from Au wire by wire bonding equipment
It is characterized by being formed.

[0011]

[0012]

[0013]

[0014]

As described above, by providing a protruding electrode having an uneven surface at the tip on the electrode pad portion of the semiconductor device as described above, when the semiconductor device is joined to the terminal electrode of the circuit board,
The bonding area between the tip surface of the protruding electrode and the terminal electrode of the circuit board can be increased, good electrical and mechanical bonding can be achieved, and a highly reliable semiconductor device package can be obtained.

[0015]

An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic explanatory view showing a method of forming an electrode for a semiconductor device according to one embodiment of the present invention, FIG. 2 is a schematic explanatory view showing an electrode structure of a semiconductor device according to the electrode forming method of the above embodiment, and FIG. FIG. 2 is a schematic explanatory view showing a mounted body of a semiconductor device having an example electrode.

1 and 2, reference numeral 1 denotes an IC substrate of a semiconductor device, 2 denotes an electrode pad, and 3 denotes a protruding electrode. 4
Denotes a flat base built in the ultrasonic transmitter, 5 denotes an uneven surface formed on the surface of the flat base 4, and 6 denotes a projecting electrode having an uneven surface formed at the tip. In FIG. 3, reference numeral 7 denotes a bonding layer made of a conductive adhesive, 8 denotes a circuit board, and 9 denotes a terminal electrode.

An outline of an electrode structure of a semiconductor device having such components, a method of forming the same, and a mounting body will be described below. First, the projection electrode 3 is formed on the electrode pad 2 of the IC substrate 1 of the semiconductor device shown in FIG. 1A by a known Au plating method. Next, FIG.
As shown in (1), the IC substrate 1 on which the protruding electrodes 3 are formed is placed face down on a flat base 4 having an uneven surface 5 formed on the surface. Further, as shown in FIG.
By operating the ultrasonic oscillator built in the device and vibrating the flat base 4, an uneven surface is formed at the tip of the protruding electrode 3. As described above, the protruding electrode 6 shown in FIG.

Further, a bonding layer 7 made of a conductive adhesive is formed on the uneven surface at the tip of the protruding electrode 6 of the semiconductor device thus obtained by a transfer method or a printing method. After positioning at a predetermined position 8 and stacking face-down, the bonding layer 7 is cured and the protruding electrode 6 is bonded to the terminal electrode 9. From the above, FIG.
A semiconductor device mounted body mounted on a circuit board face-down is obtained as shown in FIG.

When the semiconductor device electrode is connected to the terminal electrode 9 of the circuit board 8, the gap between the IC substrate 1 and the circuit board 8 can be maintained by the protruding electrode 6. For this reason, it is possible to regulate the spread of the bonding layer 7, and it is possible to obtain a semiconductor device package that can be connected at a fine pitch without risk of short-circuiting with an adjacent portion.

In addition, by using a projection electrode having an uneven surface at the tip, the bonding layer enters into the uneven portion of the projection electrode, thereby increasing the adhesive force with the terminal electrode of the circuit board. A semiconductor device can be mounted with high performance and high density.

In this embodiment, the protruding electrodes are formed by using a plating method using Au. However, if the protruding electrodes have a protruding shape, they may be formed by a method such as wire bonding using an Au wire. In this embodiment, the bonding layer made of the conductive adhesive is formed on the protruding electrode by the transfer method or the printing method. However, the bonding layer may be formed in advance on the terminal electrode of the circuit board .

[0022]

As described above, according to the present invention, an uneven surface can be easily formed at the tip of the protruding electrode of the semiconductor device, so that the versatility is extremely high. Furthermore, by providing an uneven surface at the tip of the protruding electrode of the semiconductor device, when joining the semiconductor device to the terminal electrode of the circuit board, the bonding area between the uneven surface of the protruding electrode and the terminal electrode surface of the circuit board is increased. Therefore, an extremely stable and highly reliable semiconductor device package can be obtained.

[Brief description of the drawings]

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

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

FIG. 3 is a schematic explanatory view showing a package of a semiconductor device according to an embodiment of the present invention;

FIG. 4 is a schematic explanatory view showing a conventional method for forming an electrode for a semiconductor device having a solder bump electrode.

FIG. 5 is a schematic explanatory view showing an electrode structure of a conventional solder bump electrode.

FIG. 6 is a schematic explanatory view showing a packaged semiconductor device having a conventional solder bump electrode.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 IC board of semiconductor device 2 Electrode pad 3 Protruding electrode 4 Flat base with built-in ultrasonic oscillator 5 Uneven surface 6 Protruding electrode with uneven surface formed at the tip 7 Bonding layer 8 Circuit board 9 Terminal electrode

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H01L 21/60

Claims (5)

(57) [Claims] 1. A semiconductor device mounted face-down on a circuit board, comprising: an electrode pad portion of the semiconductor device.
A protruding electrode with an uneven surface at the tip formed on top
Electrically connected to the terminal electrodes on the circuit board via the conductive adhesive
A package of a semiconductor device characterized by being connected. 2. A mounting member as claimed in claim 1, wherein the projecting electrode is characterized in that it consists of Au. 3. A method for forming an electrode for a semiconductor device mounted on a circuit board face down, comprising: forming a protruding projection electrode on an electrode pad portion of the semiconductor device; Forming an electrode for a semiconductor device, comprising: a step of pressing against a flat base having projections and depressions; and a step of forming a projection and depression surface at the tip of the protruding electrode by ultrasonically vibrating the flat base. Method. 4. The method for forming an electrode for a semiconductor device according to claim 3, wherein the protruding electrode is formed by a plating method using Au. 5. The method for forming an electrode for a semiconductor device according to claim 3, wherein the protruding electrode is formed from an Au wire by a wire bonding apparatus.