JP2000183091A - Method of mounting semiconductor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of mounting a semiconductor device, which can perform electrical connection between a semiconductor device and a wiring board without fail, even under a condition of 0.8 mm or under in electrode pitch. SOLUTION: A method of mounting a semiconductor device on a wiring board 7 has a process of forming a bump 9 on an electrode pad 8, by separating a wire 6 from the junction after jointing the end of the wire 6 onto the electrode pad 8 of the wiring board 7 by ultrasonic pressure bonding, thermal pressure bonding, or thermal pressure bonding using ultrasonic waves together, and a process of heating and joining the external lead-out electrode provided at the semiconductor device and the bump 9 made on the electrode pad 8 of the wiring board 7 with each other.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a semiconductor device mounting method suitable for mounting a semiconductor device on a wiring board.

[0002]

2. Description of the Related Art In general, types of semiconductor devices mounted on a wiring board are roughly classified into two types, a pin insertion type and a surface mounting type, according to the package form. In particular, in recent years, the surface mounting type has been widely used in order to reduce the size and weight of the semiconductor device, increase the number of electrodes, or mount the semiconductor device at a high density.

Conventionally, as a method of mounting a surface mount type semiconductor device on a wiring board, there has been a method of bonding an external lead electrode provided on the semiconductor device to an electrode pad of the wiring board without protruding from the package outer portion. Are known. Specifically, an external lead electrode is provided on the bottom surface of the semiconductor device, and a solder paste is applied using a known printing technique on an electrode pad of a wiring board on which the external lead electrode is mounted. The semiconductor device is electrically and mechanically connected by heating while pressing the external lead electrode of the semiconductor device.

[0004]

However, due to the failure of the semiconductor device, the semiconductor device mounted on the wiring board is removed, and a new semiconductor device (good product) is attached.
In other words, when the semiconductor device is to be repaired, if the pitch of the external lead-out electrodes of the semiconductor device is very narrow at 0.8 mm or less, reflow cannot be performed after partially printing and applying the solder paste. . In addition, there is a problem that it is very difficult to supply solder using a soldering iron or the like due to a narrow pad pitch. Further, if the substrate pad pitch is further narrower than 0.8 mm in the future, there is a problem that sufficient accuracy cannot be obtained by supplying the solder paste by printing, a displacement occurs, and a solder bridge occurs between pads.

The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide an electrode having a pitch of 0.1 mm.
It is an object of the present invention to provide a method of mounting a semiconductor device capable of reliably performing electrical connection between a semiconductor device and a wiring board even under a condition of 8 mm or less.

[0006]

In the method of mounting a semiconductor device according to the present invention, when mounting the semiconductor device on a wiring board, an end portion of a thin metal wire is subjected to ultrasonic compression bonding, thermocompression bonding, or the like on an electrode pad of the wiring substrate. After bonding by ultrasonic combined thermocompression bonding, a step of forming a bump on an electrode pad by separating a thin metal wire from the bonded portion, and forming an external lead electrode provided on the semiconductor device and an electrode pad on a wiring board. And bonding the heated bumps to each other by heating.

In this method of mounting a semiconductor device, the improvement in bump position accuracy and the stabilization of the amount of supply of bump size ensure that no bump-to-bump bridge occurs even with a narrower pad pitch than the solder paste printing method. The connection between the semiconductor device and the wiring board becomes possible. In addition, since the ends of the fine metal wires are joined to the electrode pads of the wiring board, and the joined portions are separated to form bumps, the semiconductor device can be easily repaired.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A specific embodiment of a method for mounting a semiconductor device according to the present invention will be described below with reference to FIGS. FIGS. 1A and 1B show a configuration example of a semiconductor device serving as a mounting component. FIG. 1A is a side view thereof, and FIG. 1B is a bottom view thereof. In the illustrated semiconductor device 1, a semiconductor chip (not shown) is mounted on a package substrate 2 serving as an interposer.
Is sealed. A plurality of external lead electrodes 4 are provided on the bottom surface of the package substrate 2.

In FIG. 1, the package substrate 2
The semiconductor device 1 of the LGA (land grid array) in which flat electrode pads are formed in the form of an array as the external lead electrodes 4 on the bottom surface of the semiconductor device is exemplified. BGA (Ball Grid Array) in which spherical solder is formed in an array on the bottom surface, and F with narrow electrode pitch
(Fine pitch) -BGA, F-LGA, and CSP (chip size package) in which the package size is reduced to the same level as the chip size can also be applied.

On the other hand, in the wiring board on which the semiconductor device 1 is mounted, bumps are formed on the electrode pads by the following method. At the time of this bump formation, as shown in FIG. 2, a wire (a thin metal wire) 6 passed through a wedge tool 5 is used to form an electrode pad 8 of a wiring board 7.
The bump 9 is formed thereon. As the wiring board 7, an organic substrate typified by glass epoxy or an inorganic substrate such as ceramics is applied. As the electrode pad 8, gold,
Silver, copper, palladium, an alloy containing these, or the like is used. Further, as the bump 9 (wire material of the wire 6), for example, Pb (lead), Sn (tin), In (indium), Zn (zinc), silver, bismuth, or an alloy containing these is applied.

In FIG. 2, for example, Sn-Pb is formed on an electrode pad 8 of a wiring board 7 by using a wedge tool 5.
The tip of the wire 6 made of an alloy is pressed, and an ultrasonic wave is applied to the tip of the pressed wire 6 (a portion to be the bump 9) to compress the wire.
To form

The forming conditions at this time include, for example, using a wire 6 having a wire diameter of 80 μm, pressing the tip of the wire 6 with a wedge tool 5, and in this state, applying 20 μm to the tip of the wire.
g to 50 g while applying a frequency of 60 kHz to 20
Ultrasonic waves of 5mW to 50mW at 0kHz for 10msec ~
In addition, the substrate temperature is heated from room temperature to 250 ° C. for 50 ms, and the tip of the wire (the portion to be the bump 9) is pressed against the electrode pad 8.

When the wire tip is pressed, the tip of the wire 6 is pressed against the electrode pad 8 while the wedge tool 5 is lowered, as shown in FIG.
At this time, a protrusion 5a (FIG.
) Is provided, and the wire 6 is
May be crushed.

Next, as shown in FIG. 3 (b), while the tip of the wire 6 is pressed by the wedge tool 5, under the above forming conditions (ultrasonic waves, heat or a combination thereof)
The tip of the wire 6 is bonded (press-bonded) to the electrode pad 8. Thereafter, the clamper 10 attached to the wedge tool 5 moves in the direction of the arrow with the clamped state released (open state).

Thereafter, after moving by a predetermined amount, as shown in FIG. 3C, the clamper 10 is in a clamped state (closed state).
In this state, the wedge tool 5 and the clamper 10 further move in the length direction of the wire 6 (the direction of the arrow). This movement cuts the wire 6. When the wedge tool 5 has a projection 5a, a pulling force acts on a portion of the wire 6 where the wire 6 is crushed by the projection 5a. (The part to be the bump 9).

Subsequently, as shown in FIG. 3D, after the wedge tool 5 retreats upward, it moves toward the next joining point.

According to the above procedure, a low-melting metal having a diameter of, for example, 70 μm (500 ° C.)
A bump 9 made of a metal that melts in the following is formed.
Thereafter, the bumped wiring board 7 may be partially heated to melt the bumps 9 to form the bumps into spherical or hemispherical shapes.

After preparing the semiconductor device 1 and the wiring board 7 with bumps in this way, thereafter, the semiconductor device 1 is mounted on the wiring board 7 via the external lead electrodes 4 and the bumps 9 corresponding to each other.

More specifically, first, a flux is applied to the bumps 9 formed on the wiring board 7, and then the semiconductor device 1 is mounted on the wiring board 7. At this time, after the semiconductor device 1 is vacuum-adsorbed by the mount tool,
The semiconductor device 1 is aligned with the wiring board 7 by the alignment operation of the mount tool.

As a result, as shown in FIG. 4, the external lead-out electrodes 4 formed on the semiconductor device 1 and the bumps 9 formed on the wiring board 7 corresponding thereto are in a state of facing each other. Therefore, in this state, the external lead-out electrode 4 and the bump 9 are brought into contact with each other while being heated, so that they are joined by heat melting. The heating method for bonding includes the semiconductor device 1 and the wiring board 7.
The semiconductor chip 1 is aligned and mounted on the wiring board 7 while locally heated by a dryer or the like, so that the corresponding external lead-out electrodes 4 and bumps 9 can be joined to each other. .

Further, since the ends of the wires 6 are bonded to the electrode pads 8 of the wiring board 7 and the bonding portions are separated to form the bumps 9, the electrode pitch of the wiring board 7 is repaired when the semiconductor device 1 is repaired. The bump can be easily formed even if the width is small. Further, when the bump shape is not spherical or hemispherical, it is not necessary to pass the wiring board 7 through a reflow furnace when forming the bumps on the electrode pads 8 of the wiring board 7. It can also be simplified.

[0022]

As described above, according to the semiconductor device mounting method of the present invention, when the external lead electrode on the semiconductor device side and the bump formed on the wiring substrate side are joined, the electrode pad of the wiring substrate is used. The electrodes of the semiconductor device and the wiring board can be bonded to each other while maintaining the bonding state between the bumps and the bumps, and the occurrence of bridges between the bumps can be prevented.
Even under the following conditions, the electrical connection between the semiconductor device and the wiring board can be reliably performed. Furthermore, since the ends of the fine metal wires are joined to the electrode pads of the wiring board, and the joined portions are separated to form bumps, the semiconductor device can be easily repaired.

[Brief description of the drawings]

FIG. 1 is a diagram (part 1) illustrating an embodiment of a semiconductor device mounting method according to the present invention.

FIG. 2 is a diagram (part 2) illustrating an embodiment of a semiconductor device mounting method according to the present invention.

FIG. 3 is a diagram (part 3) for explaining an embodiment of a semiconductor device mounting method according to the present invention;

FIG. 4 is a view (No. 4) for explaining an embodiment of a semiconductor device mounting method according to the present invention;

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Semiconductor device, 4 ... External extraction electrode, 6 ... Wire (metal thin wire), 7 ... Wiring board, 8 ... Electrode pad, 9 ... Bump

Claims (2)

[Claims] 1. A method of mounting a semiconductor device on a wiring board, comprising: bonding an end of a thin metal wire to an electrode pad of the wiring board by ultrasonic compression bonding, thermocompression bonding, or thermocompression combined with ultrasonic bonding; Forming a bump on the electrode pad by separating the thin metal wire from; and heating the external lead electrode provided on the semiconductor device and the bump formed on the electrode pad of the wiring board to each other. Bonding the semiconductor device. 2. The semiconductor device according to claim 1, further comprising, after forming the bump on the electrode pad of the wiring substrate, heating and melting the bump to form a spherical or hemispherical shape. Implementation method.