JPH10154766A - Manufacture of semiconductor package and semiconductor package - Google Patents

Abstract

PROBLEM TO BE SOLVED: To arrange solder balls with good accuracy and also to inhibit the balls from rolling by a method wherein recessed parts are formed in ball pad lands to be mounted with the solder balls and mounting parts for the solder balls are made to expose through resists. SOLUTION: Recessed parts 4 are respectively formed in the centers of ball pad lands 2 formed on a wiring board 1 by metallic molding. Resists 5 are applied on the board 1 with the recessed parts 4 formed therein. The resists 5 are exposed without being applied on mounting parts 6, on which the balls 8 are mounted, on the lands 2. An Au-Ni plating 7 is applied to the mounting parts 6 for the solder balls 8. Then, the solid solder balls 8 are arranged on the mounting parts 6 for the solder balls 8. The surfaces of the arranged solder balls 8 surface-contact the recessed part 4 formed in the lands 2. The mounting positions of the balls 8 are accurately positioned by the recessed parts 4 and at the same time, the resists 5, through which the mounting parts 6 only are exposed, prevent the balls 8 from rolling.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor package having a semiconductor chip mounted thereon and a wiring board used for connection to an external circuit. More specifically, the present invention relates to a semiconductor package in which solder balls are mounted as terminals for connecting to an external circuit. Ball grit array.

[0002]

2. Description of the Related Art Conventionally, there is a quad flat package (hereinafter referred to as QFP) as an apparatus for connecting a chip to an external circuit such as a printed wiring board.

In this QFP, a chip and an inner lead of a lead frame are connected by wire bonding or the like inside a package, a region including the chip is sealed with a resin to form a package, and outer leads of the lead frame are formed from four sides thereof. , And the lead is formed in a gull-wing shape to be connected to an external circuit.

However, recent demands for a semiconductor package include an improvement in mounting density and a reduction in area required for mounting. There is a ball grid array (hereinafter, referred to as BGA) as a semiconductor package connected to an external circuit to meet the needs. In the BGA, a wiring pattern is formed on a wiring board, and it is easy to mount a plurality of chips on one module using the wiring pattern.

A general BGA type semiconductor package is:
A copper-clad laminate for a printed wiring board is used as a base material, and this copper-clad laminate is processed by a method such as a photoetching method to form a chip mounting portion and a wiring portion.

When a spherical ball pad land is provided on the lower surface of the substrate in order to directly connect the wiring substrate to an external circuit, the shape and size of the solder ball depend on the number of electrode terminals and the wiring density. I have.

For this reason, when the wiring density increases and the number of electrode terminals increases in recent years, the area of the ball pad land decreases, and the area for mounting the solder ball becomes very small. It had to be placed and glued. However, as a method of bonding and arranging the solder ball on the ball pad land, a solder paste is applied to the ball pad land in advance, and a mask having a through hole facing the position of the ball pad land is overlaid on the wiring board, and A spherical solder ball was rolled into the mask and temporarily fixed, then the solder was melted and the solder ball was bonded.

However, in this method, the solder ball may be displaced from the center of the ball pad land, and when the solder is melted, the solder ball comes into contact with the adjacent solder ball, causing poor adhesion, or the ball pad land and the solder ball may be in contact with each other. Because of the small contact area, the adhesive force was reduced, and poor adhesion sometimes occurred.

[0009]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has as its object the following:
In a method of manufacturing a BGA type semiconductor package and a BGA semiconductor package, a solder ball is accurately arranged on a ball pad land on which a wiring board is formed to improve the adhesive strength between the wiring board and the solder ball.

[0010]

According to a first aspect of the present invention, there is provided a method of manufacturing a semiconductor package, wherein solder balls are mounted on a lower surface of a wiring board in a substantially matrix shape so as to be directly surface-mounted on another external circuit. In the method of manufacturing a ball grid array type semiconductor package, a ball pad land and a circuit pattern which are terminations for directly surface mounting to another external circuit are formed on the lower surface of the wiring board, and the solder balls of the ball pad land are mounted. A concave portion was formed by molding in a position to be formed, a resist was applied so that a mounting portion of the solder ball constituted by the concave portion was exposed, and further, an Au-Ni plating was applied to the mounting portion of the solder ball. Thereafter, a solder ball is mounted.

A semiconductor package according to a second aspect of the present invention is a ball grid array type semiconductor package in which solder balls are mounted on a lower surface of a wiring board in a substantially matrix shape so as to be directly surface-mounted on another external circuit. A concave portion is formed in the ball pad land on which the solder ball is mounted, and the mounting portion is exposed from the resist.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be specifically described below with reference to the drawings showing the steps of a manufacturing method.

FIG. 1 is a sectional view of a semiconductor package according to an embodiment of the present invention. FIG. 2 is an explanatory view showing steps of a method for manufacturing a semiconductor package according to one embodiment of the present invention.

As shown in the drawing, the semiconductor package of the present invention has the same configuration as a wiring board 1 such as a printed wiring board, but solder balls 8 are arranged on ball pad lands 2 formed on the back surface of the wiring board 1. Have been.

First, a ball pad land 2 is formed on the back surface of the wiring substrate 1 by using a patterning method such as etching. Here, when the wiring board 1 uses a wiring board 1 to which a copper foil is adhered, a photo-etching process can be used, and when the wiring board 1 with an exposed insulating portion is used, a plating method is used. A circuit pattern such as the ball pad land 2 can be formed. Next, a recess 4 is formed at the center of each ball pad land 2 in the center of the ball pad land 2 formed on the wiring board 1 by die molding. As shown in the figure, a mold 3 used in the embodiment of the present invention is a mold 3 formed to face the ball pad land 2 and has a shape such that a pin is set up on the ball pad land 2. When the ball pad land 2 is pressed and molded, the concave portion 4 having a spherical surface can be formed at the center of the ball pad land 2. (Refer to FIG. 2) Then, a resist 5 is
Is applied. As shown in the figure, the resist 5 is not applied to the mounting portion 6 of the ball pad land 2 on which the solder ball 8 is mounted, and is exposed. As a method of not applying the resist 5 only to the mounting portion 6 of the ball pad land 2 as described above, an unnecessary portion is removed by applying the resist 5 on the entire surface or applying a resist film and then performing exposure and development. (See FIG. 2) Then, the Au-Ni plating 7 is applied to the mounting portion 6 of the solder ball 8 of the ball pad land 2. Next, a solid spherical solder ball 8 is arranged on the mounting portion 6 of the solder ball 8 (see FIG. 2). The surface of the arranged solder ball 8 comes into surface contact with the concave portion 4 formed in the ball pad land 2. (Refer to FIG. 2) By reflow heating the solder balls 8 arranged on the ball pad land 2 as described above, as shown in FIG.
The solder balls 8 can be mounted on the wiring board 1.

The recess 4 formed in the ball pad land 2 accurately determines the mounting position of the solder ball 8, and the solder ball 8 is rolled by the resist 5 exposed only in the mounting portion 6 of the ball pad land 2. It prevents you from moving.

[0017]

As described above, according to the method of manufacturing a semiconductor package and the semiconductor package of the present invention, solder balls are mounted on the lower surface of the wiring board 1 in a substantially matrix shape so as to be directly surface-mounted on another external circuit. In the ball grit array type semiconductor package, the concave portion is formed in the ball pad land on which the solder ball is mounted, and the mounting portion is exposed from the resist, so that the solder ball can be accurately arranged and rolled. Can be suppressed. Further, since the solder ball and the recess are in surface contact, the contact area is increased, and the bonding strength can be improved. In addition, since the mounting portion of the ball pad land is exposed from the resist, the flow of solder can be prevented when the resist applied to the periphery mounts the solder ball.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a semiconductor package according to an embodiment of the present invention.

FIG. 2 is an explanatory diagram illustrating a method for manufacturing a semiconductor package according to an embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Wiring board 2 Ball pad land 3 Die 4 Concave part 5 Resist 6 Mounting part 7 Au-Ni plating 8 Solder ball

Claims (2)

[Claims] In a method of manufacturing a ball grid array type semiconductor package in which solder balls are mounted on a lower surface of a wiring board in a substantially matrix shape so as to be directly surface-mounted on another external circuit, another method is employed in which a lower surface of the wiring substrate is mounted on a lower surface of the wiring board. A ball pad land and a circuit pattern to be a terminal for direct surface mounting on an external circuit are formed, and a concave portion is formed by molding at a position where the solder ball of the ball pad land is mounted, and the concave portion is constituted by the concave portion. A method of manufacturing a semiconductor package, comprising applying a resist so that a solder ball mounting portion is exposed, further applying Au-Ni plating to the solder ball mounting portion, and then mounting the solder ball. 2. A ball grid array type semiconductor package in which solder balls are mounted on a lower surface of a wiring board in a substantially matrix shape so as to be directly surface-mounted on another external circuit. A semiconductor device, wherein a concave portion is formed in the semiconductor package, and a mounting portion is exposed from the resist.