JP3243906B2 - Method for joining semiconductor device to external terminal - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for joining a semiconductor device to an external terminal. More specifically, the present invention relates to a bonding method capable of reliably welding a semiconductor device and an external terminal using laser light.

[0002]

2. Description of the Related Art When a connection terminal for external conduction and an external terminal of a semiconductor device having a semiconductor chip mounted on a printed circuit board are bonded to the external terminal, the connection is made at a fine pitch in response to the recent increase in the density of circuit boards. It is performed by a wire bonding method or a bump method that can be used.

In the case of bonding by a wire bonding method, external terminals are fixed to the peripheral portion of the semiconductor device with a double-sided tape or the like, and the end of the external terminal and a connection terminal for external conduction of the semiconductor device are bonded by a bonding wire. are doing. In the case of connection by a bump method, a bump is formed on a connection terminal of a semiconductor device, and an external terminal is bonded to the bump by thermocompression bonding.

However, when the semiconductor device and the external terminal are joined by these methods, the joining strength is not sufficient, and the wire is cut or the bump metal is cracked, resulting in poor connection reliability. There was a problem that it was enough. In addition, a noble metal such as gold is often used as a connection material, and there has been a problem that the connection cost increases.

For this reason, as shown in FIG. 5A, an external terminal is connected to a connection terminal portion 3a for external conduction of a printed circuit board 1 of a semiconductor device comprising an insulating layer 2 and a conductor layer 3 sandwiching the insulating layer. 4 is not fixed with an adhesive, but is positioned and closely contacted using a holding jig, and as shown in FIG.
Laser light h such as a YAG laser is applied to the tip of the external terminal 4.
Irradiation with ν has been attempted to weld the external terminal 4 and the connection terminal portion 3a of the semiconductor device with high bonding strength (FIG. 5C).

[0006]

However, as the external terminals 4 become finer in pitch, it becomes more difficult to make the external terminals 4 and the connection terminal portions 3a of the semiconductor device in close contact with each other at a predetermined position using only a holding jig. Therefore, FIG.
As shown in the figure, the external terminal 4 is lifted up from the connection terminal portion 3a or deviated from a predetermined position so that they do not come into close contact with each other. There was a problem that welding was not possible.

An object of the present invention is to solve the above-mentioned problems of the prior art, and an object of the present invention is to ensure that a semiconductor device and an external terminal can be securely welded at a predetermined position by using a laser beam. And

[0008]

SUMMARY OF THE INVENTION The present inventor has proposed that when a semiconductor device and an external terminal are welded and joined by using a laser beam, the external terminal is preliminarily fixed to a semiconductor substrate using an adhesive, and at that time the external terminals so as to cancel the thickness of the adhesive in advance by the de-pressed to contact wolfberry to found that the above object can be achieved, thereby completing the present invention.

That is, according to the present invention, an external terminal is temporarily fixed to a peripheral portion of a semiconductor device with an adhesive, and a tip portion of the external terminal is depressed in advance by a distance substantially corresponding to the thickness of the adhesive, whereby an external terminal is formed. The terminal of the terminal is brought into close contact with the connection terminal for external conduction of the semiconductor device, and the external terminal is welded to the connection terminal of the semiconductor device by irradiating a laser beam to the end of the external terminal. And a method for joining a semiconductor device and an external terminal.

[0010]

[0011]

In the bonding method according to the present invention, the connection terminals for external conduction of the printed circuit board of the semiconductor device and the external terminals are temporarily fixed with an adhesive. Therefore, the positioning accuracy between the external terminal and the semiconductor device is improved. Further, the tip of the external terminal is depressed in advance toward the semiconductor device by a distance substantially corresponding to the thickness of the adhesive. This makes it possible to bring the external terminals into close contact with the connection terminal portions of the semiconductor device.

Although not within the scope of the present invention, a concave portion having a depth substantially corresponding to the thickness of the adhesive is formed in advance on the external terminal or the surface of the semiconductor device, and the adhesive is put into the concave portion to bring the two into close contact. It can be temporarily fixed while it is kept .

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The joining method of the present invention will be described below in detail with reference to the drawings. In each of the drawings, the same numbers indicate the same or equivalent components.

FIGS. 1 and 2 are process diagrams of the bonding method of the present invention when depressing external terminals, FIG. 3 is a process diagram when concave portions are provided in the external terminals, and FIG.
FIG. 4 is a process diagram when a concave portion is provided on the semiconductor device side.

In the method shown in FIG. 1, a double-sided adhesive tape 5 such as a thermoplastic polyimide tape is first adhered to the periphery of the printed circuit board 1 of the semiconductor device as an adhesive (FIG. 1A).

Next, after positioning the external terminal 4 whose front end 4a has been depressed in advance on the double-sided adhesive tape 5, the external terminal 4 is crimped and temporarily fixed (FIG. 2B).

Next, the tip of the external terminal is irradiated with a laser beam hν capable of supplying a sufficient welding energy, for example, a YAG laser beam in the form of a small spot (for example, a spot having a diameter of 200 μm) (FIG. 2C), Is welded to the connection terminal portion 3a and the external terminal 4 (FIG. 4D).
Thereby, the connection terminal portion 3a and the external terminal 4 of the semiconductor device
Can be joined with high connection strength, and the connection reliability can be significantly improved.

FIG. 2 shows an example in which an ultraviolet-curing resin is used as an adhesive. First, a printed circuit board 1 of a semiconductor device is used.
The ultraviolet curable resin 6 is supplied as an adhesive to the peripheral portion of the substrate by a dispenser or the like (FIG. 3A).

Next, the external terminal 4 whose tip 4a is depressed in advance from the ultraviolet curing resin 6 is aligned and brought into close contact with the connection terminal 3a of the semiconductor device (FIG. 2B).

Next, while the tip portion 4a of the external terminal 4 is kept in close contact with the connection terminal portion 3a, ultraviolet rays U
By irradiating V, the external terminals 4 are temporarily fixed to the semiconductor device (FIG. 3C).

Next, the tip of the external terminal 4 is irradiated with a laser beam hν capable of supplying a sufficient welding energy (FIG. 3D), and the connection terminal portion 3a of the semiconductor device and the external terminal 4 are welded ( FIG. Thereby, the connection terminal portion 3a and the external terminal 4 of the semiconductor device can be joined with high connection strength, and the connection reliability can be significantly improved.

In the method shown in FIG. 3, first, a double-sided adhesive tape 5 such as a thermoplastic polyimide tape is attached to the periphery of the printed circuit board 1 of the semiconductor device as an adhesive (FIG. 3A). .

On the other hand, the external terminals 4 are aligned so that the double-sided adhesive tape 5 is fitted into the concave portions 4b formed in advance by a half-etching method or the like (FIG. 4B), and are temporarily fixed by heat compression. . This ensures that the distal end portion 4a of the external terminal 4 and the connection terminal portion 3a for external conduction of the semiconductor device are in close contact with each other (FIG. 3C).

Next, the tip of the external terminal is irradiated with a laser beam hν capable of supplying a sufficient welding energy (FIG. 4 (d)), and the connection terminal portion 3a of the semiconductor device and the external terminal 4 are welded (see FIG. Figure (e). Thereby, the connection terminal portion 3a and the external terminal 4 of the semiconductor device can be joined with high connection strength, and the connection reliability can be significantly improved.

In the method shown in FIG. 4, instead of forming the recess 4b in the external terminal 4, a recess 2b is formed in the periphery of the printed circuit board 1 of the semiconductor device (FIG. 4A), and the recess 2b is formed. In this example, the double-sided adhesive tape 5 is adhered to the inside, and the external terminals 4 are temporarily fixed thereon ((b) in FIG. 3).

After the external terminals 4 are temporarily fixed, the external terminals 4
Is irradiated with a laser beam hν on the tip 4a (FIG. 3 (c)),
The connection terminals 3a of the semiconductor device and the external terminals 4 are welded and joined (FIG. 4D).

[0027]

According to the method for joining a semiconductor device and an external terminal of the present invention, the semiconductor device and the external terminal can be reliably welded and joined at a predetermined position by using a laser beam.

[Brief description of the drawings]

FIG. 1 is a process chart of a bonding method of the present invention.

FIG. 2 is a process chart of the bonding method of the present invention.

FIG. 3 is a process diagram of a bonding method serving as a reference .

FIG. 4 is a process diagram of a bonding method serving as a reference .

FIG. 5 is a process chart of a conventional bonding method.

FIG. 6 is an explanatory diagram of a connection failure state between an external terminal and a semiconductor device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Wiring circuit board 2 Insulating layer 3 Conductive layer 3a Connection terminal part 4 External terminal 4a External terminal tip part 5 Double-sided adhesive tape 6 Ultraviolet curing resin hν laser beam

Claims (1)

(57) [Claims] When an external terminal is temporarily fixed to a peripheral portion of a semiconductor device with an adhesive, the distal end of the external terminal is depressed in advance by a distance substantially corresponding to the thickness of the adhesive, so that the external terminal can be fixed. A semiconductor, wherein the tip is brought into close contact with a connection terminal for external conduction of the semiconductor device, and a laser beam is applied to the tip of the external terminal to weld the external terminal to the connection terminal of the semiconductor device. How to join the device to external terminals.