JPH11163245A - Ball grid array type semiconductor device - Google Patents

Abstract

[PROBLEMS] To provide a BGA type semiconductor device using a lead frame with improved bonding properties and package reliability. SOLUTION: A semiconductor chip is mounted on an island of a lead frame, has a ball mounting portion, and has an inner tip portion arranged around the island. In a ball grid array type semiconductor device in which at least a semiconductor chip and a wire are sealed with a resin and conductive balls are attached to ball attachment portions of inner leads, leads are connected to a side different from the electrode pad side of the lead frame. A fixing tape for supporting the frame is provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a ball grid array type semiconductor device, and more particularly to a ball grid array type semiconductor device using a lead frame.

[0002]

2. Description of the Related Art As the number of pins of a package increases with the increase in the degree of integration of a semiconductor chip, a QFP (Qua) in which external leads are arranged only in a peripheral portion of the package is accompanied.
d Flat Package) or QFJ (Quad
In place of Flat J-leaded Package, etc., a ball grid array (BGA) type package in which external terminals are arranged in a plane has been increasingly used.
Usually, a BGA has a structure in which a printed circuit board is used as a wiring base material.
A power supply layer and a GND layer are provided to strengthen the ND circuit,
Furthermore, since the wiring is multilayered for higher mounting density and the wiring layers are connected by through holes, the package becomes very expensive compared to QFP and QFJ using a lead frame.

Accordingly, a BGA using an inexpensive lead frame as a wiring base has been developed and put into practical use.
Hereinafter, with reference to FIG.
The GA type semiconductor device will be described. As shown in FIG. 5A, a lead frame having an island 2 on which a semiconductor chip 1 is mounted, and an inner lead 3 having a solder ball attaching portion 4 and having an inner tip portion arranged around the island. Is prepared, and the portion of the inner lead 3 excluding the solder ball attachment portion 4 is half-etched to be thin. Further, a fixing tape 5 is attached to the half-etched surface side of the tip of the inner lead to prevent deformation of the inner lead. Then, as shown in FIG. 5B, the semiconductor chip 1 is mounted on the island 2 via an adhesive, and the electrode pads of the semiconductor chip 1 and the inner end portions of the inner leads 3 are connected by wires 6. Then, FIG.
As shown in (c), the semiconductor chip 1, the island 2, the inner leads 3 and the wires 6 are sealed with a sealing resin 8 by the transfer molding method, and finally, the solder balls 7 are attached to the solder ball attaching portions 4 of the inner leads 3. To complete the manufacturing process of the conventional BGA type semiconductor device.

[0004] A BGA type semiconductor device using a lead frame is known from Japanese Patent Application Laid-Open No. 8-139259 shown in FIG. JP-A-8-139259
In the semiconductor device described in Japanese Patent Application Laid-Open Publication No. H11-207, the external terminal portions of the inner leads are arranged two-dimensionally along the lead forming surface.

[0005]

The first problem is that the bonding property is remarkably deteriorated, and an open defect or insufficient bonding strength occurs. The reason is,
A fixing tape for preventing inner lead deformation is provided on the lower surface of the tip of the inner lead that performs wire bonding,
Usually, a polyimide-based material is used. However, due to the effect of the elastic modulus (low elasticity) of the fixing tape, the ultrasonic wave and the weight received during bonding may be absorbed. Further, when the ultrasonic wave and the load are increased in order to improve the bonding strength, there is a problem that the wire is deformed (curled) due to the influence of the ultrasonic vibration.

The second problem is that the reliability of the package is reduced. The reason is that since the fixing tape (polyimide tape) having high water absorption is exposed on the surface of the package, the moisture resistance is deteriorated and moisture easily enters the inside of the package. As a result, problems such as package cracking, migration, and corrosion of aluminum wiring are likely to occur.

It is an object of the present invention to provide a BGA type semiconductor device using a lead frame having improved bonding properties and package reliability.

[0008]

In a ball grid array type semiconductor device according to the present invention, a semiconductor chip is mounted on an island of a lead frame, and a ball mounting portion is provided. The inner tip of the inner lead and the electrode pad of the semiconductor chip are connected by a wire, at least the semiconductor chip and the wire are sealed with a resin, and a conductive ball is attached to a ball attachment portion of the inner lead. In the above-mentioned ball grid array type semiconductor device, a fixing tape for supporting a lead frame is provided on a side of the lead frame different from the solder ball side.

Further, in the ball grid array type semiconductor device according to the present invention, in the above-mentioned ball grid array type semiconductor device, the fixing tape is mounted on the lead frame having substantially the same height as the semiconductor chip mounting surface of the island. It is characterized by being provided.

Further, in the ball grid array type semiconductor device according to the present invention, in the above-mentioned ball grid array type semiconductor device, the fixing tape is provided on a lead frame between a terminal of the semiconductor chip and a bonding portion on the lead frame. It is characterized by being arranged in.

[Operation] In a lead frame used for a BGA type semiconductor device, a fixing tape for supporting the lead frame is provided on a side of the lead frame different from the solder ball side, thereby suppressing inner lead deformation and bonding. The fixing tape that deteriorates the bonding property can be removed immediately below the bonding step, so that the bonding property is improved, and since the fixing tape is not exposed on the package surface, the moisture resistance is increased and the reliability of the package can be improved. .

[0012]

Next, embodiments of the present invention will be described in detail with reference to the drawings.

Referring to FIG. 1, a ball grid array type semiconductor device according to an embodiment of the present invention comprises an island 2 on which a semiconductor chip 1 is mounted and an inner lead 3 having a solder ball mounting portion 4. A lead frame in which a portion excluding the solder ball attaching portion 4 is half-etched is used. In this manufacturing method, first, the inner lead 3 is etched into a predetermined wiring pattern as shown in FIG. 2, plated, and then fixed with a fixing tape 5 to prevent deformation of the inner lead 3.
At this time, in order to suppress deformation of the inner lead 3 on the surface different from the solder ball mounting portion 4, that is, the surface on which wire bonding is performed, and the bonding point, Paste on the outside area. Thus, a lead frame for a BGA type semiconductor device of the present embodiment as shown in FIG. 3A is obtained. The material of the lead frame at this time is not particularly limited, but it is effective to use a copper-based metal in consideration of electrical and thermal characteristics. In addition, the lead frame of the present embodiment is subjected to half-etching except for the solder ball attachment portion of the inner lead in order to facilitate fine processing.However, in order to manufacture a stable lead frame, the thickness of the lead frame is required. It is preferable to use a material having a thickness of about 0.125 mm, perform half etching of about 80 μm, and reduce the thickness of the remaining wiring to about 40 μm. The reason is that if the thickness of the lead frame is increased, the amount of half-etching must be increased, which makes it difficult to control the manufacturing process. Also, if the plate thickness of the lead frame is reduced, it becomes difficult to control the half etching, and the lead frame is easily deformed.

Using the thus obtained lead frame,
First, as shown in FIG. 3B, the semiconductor chip 1 is mounted on the island 2 via an adhesive such as Ag paste.
An electrode pad of the semiconductor chip 1 and one end of an inner lead 3 having one end arranged around the island 2 are connected by a wire 6, and as shown in FIG. 3C, the semiconductor chip 1, the island 2, the inner lead 3 and the wire 6 are sealed with a resin 8, and the solder balls 7 are attached to the solder ball attachment portions 4 of the inner leads 3. At this time, the wire bonding is performed at a position beyond the fixing tape 5 provided at the tip of the inner lead. Thus, the BGA type semiconductor device of the present invention is obtained.

[0015]

As described above, according to the present invention, since there is no fixing tape just below the position where the bonding is performed, which causes the bonding property to deteriorate, the ultrasonic waves and the weight at the time of bonding are sufficiently transmitted to the leads. Stable bonding strength can be obtained. Therefore, the bonding property is improved.

A second effect is that the reliability of the package is improved.

Further, according to the present invention, since the fixing tape is not exposed on the package surface, the moisture resistance of the package is increased, and the package crack, migration, aluminum wiring corrosion and the like during reflow are eliminated. Therefore, the reliability of the package is improved.

Further, according to the present invention, deformation of the wire is suppressed. First, since there is no fixing tape immediately below the position where bonding is performed, which causes deterioration in bonding properties, it is not necessary to apply excessive ultrasonic waves and weight during bonding, and wire deformation (curling) during bonding is suppressed. Because you can do it. In addition, since the fixing tape is provided at the tip of the inner lead and the wire is connected to the inner lead beyond the fixing tape, the fixing tape can hold the wire, so that the resin flow at the time of resin sealing is performed. This is because deformation of the wire can also be suppressed.

[Brief description of the drawings]

FIG. 1 is a sectional view of a ball grid array type semiconductor device according to an embodiment of the present invention.

FIG. 2 is a plan view of a ball grid array type semiconductor device according to an embodiment of the present invention.

FIG. 3 is a sectional view illustrating a manufacturing process of the ball grid array type semiconductor device according to the embodiment of the present invention;

FIG. 4 is a cross-sectional view of a conventional ball grid array type semiconductor device.

FIG. 5 is a sectional view showing a manufacturing process of a ball grid array type semiconductor device according to a conventional example.

FIG. 6 is a plan view of a ball grid array type semiconductor device according to another conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Semiconductor chip 2 Island 3 Inner lead 4 Solder ball attachment part 5 Fixing tape 6 Wire 7 Solder ball 8 Resin

Claims (3)

[Claims] A semiconductor chip is mounted on an island of a lead frame, has a ball mounting portion, and has an inner tip portion arranged around the island and an inner tip portion of an inner lead and an electrode pad of the semiconductor chip. Are connected by a wire, at least the semiconductor chip and the wire are sealed with a resin, and a conductive ball is attached to a ball attachment portion of the inner lead. A ball grid array type semiconductor device, wherein a fixing tape for supporting a lead frame is provided on a side different from the side. 2. The ball grid array type semiconductor according to claim 1, wherein the fixing tape is provided on the lead frame having substantially the same height as the semiconductor chip mounting surface of the island. apparatus. 3. The ball according to claim 1, wherein the fixing tape is provided on a lead frame between a terminal of the semiconductor chip and a bonding portion on the lead frame. Grid array type semiconductor device.