JPH07211814A - Surface mount semiconductor package and mother board mounting method of surface mount semiconductor package - Google Patents

Abstract

PURPOSE:To ensure soldering connection between pads for external connection and pads for external connection on a mother board, by forming the pads for external connection on the rear, and forming through hole conducting paths in the pads for external connection which paths are electrically connected with circuit patterns on the surface. CONSTITUTION:Through hole conducting paths 2 on a board 1 are formed in order to connect circuit patterns 3 on the upper surface with pads for external connection on the lower surface. A part of the circuit patterns 3 is connected with a semiconductor chip by wire bonding. Other part of the circuit patterns 3 is connected with the aperture parts of the through hole conducting paths 2, and a series of conducting circuits is formed. The pad for external connection has the aperture part of the through hole conducting path 2 penetrating the board from the upper surface of the board 1 constituting a surface mount semiconductor package. When reflow soldering is performed, solder filling can be confirmed on the inner wall of the through hole conducting path formed in the surface mount semiconductor package, so that high reliability can be obtained for physical connection and electric connection.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a surface mounting semiconductor package and a mounting method for mounting the surface mounting semiconductor package on a mother board.

[0002]

2. Description of the Related Art Conventionally, semiconductor packages used in electronic equipment, especially leadless semiconductor packages, are
There are leadless chip carriers (hereinafter, LCC) and the like.
As an example of the LCC, as shown in the perspective view of FIG. 5, electrode pads (8) are provided on all four side surfaces of a ceramic substrate, a plastic substrate, or the like, and a semiconductor is provided at the center of the upper surface of the substrate (1). A leadless surface mount in which a recess (9) for mounting a chip is formed and a circuit pattern (3) for connecting the electrode pad (8) and the semiconductor chip is formed around the recess (9). It is a type package. FIG. 6 is a partially cutaway enlarged perspective view of the above LCC mounted on a printed wiring board serving as a mother board, showing the external connection pads (5) formed on the upper surface of the printed wiring board (4) to be mounted. The electrode pads (8) formed on the side surfaces of the LCC are opposed to each other and are connected to the external connection pads (5) of the printed wiring board (4) by reflow soldering.
A series of conductive circuits are formed with the circuit pattern (3) on the upper surface of C, the electrode pad (5), and the external connection pad (5). However, in the above LCC, the electrode pad (5)
Is formed into a semi-cylindrical shape, and therefore, the peeling or cracking of the plating of the electrode pad (5) occurs due to the stress generated by cutting during processing, and the soldering is sufficient, resulting in poor conduction. There is such a problem.

[0003]

The present invention has been made in view of the above circumstances, and its object is to:
When this surface-mounting semiconductor package is mounted on a mother board such as a printed wiring board and used, the external connection pad of the surface-mounting semiconductor package and the external connection pad on the mother board are securely connected by soldering, Surface mounting semiconductor package capable of improving the reliability of the conduction circuit of the same, and a mounting method with high reliability of electrical connection of the surface mounting semiconductor package, which is mounted on a mother board using the surface mounting semiconductor package. To provide.

[0004]

A semiconductor package for surface mounting according to claim 1 of the present invention has a semiconductor chip mounted on the front surface, a circuit pattern (3) for connecting to the semiconductor chip, and a pad for external connection on the back surface. (6) In the external connection pad (6), a through-hole conductive path (2) that is electrically connected to the circuit pattern (3) on the surface is formed (2).

According to a second aspect of the present invention, there is provided a method for mounting a surface-mounting semiconductor on a mother board, wherein when mounting the surface-mounting semiconductor package according to the first aspect on a mother board, pads (6) (5) for external connection to each other. Are matched and soldered into the through-hole conductive path (2) to connect the circuits to each other, and the surface mounting semiconductor package (1) is mounted on the motherboard.

[0006]

According to the surface mounting semiconductor package of the present invention, the circuit pattern (3) formed on the surface of the surface mounting semiconductor package (1) and the external connection pad (6) formed on the back surface are through holes. Since it is conducted by the conductive path (2), when soldered to the printed wiring board (4) or the like on which the semiconductor package for surface mounting (1) is mounted by reflow soldering, the surroundings are closed and the through hole conductive path is formed. Solder rises from the opening of (2) toward the inner wall like a capillary phenomenon. Due to solder rise,
It is possible to secure the connection between the surface-mounting semiconductor package (1) and the printed wiring board (4).

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

[0008]

1 is a perspective view of a surface-mounting semiconductor package according to an embodiment of the present invention. FIG. 2 is a partially cutaway enlarged view of a semiconductor package for surface mounting according to an embodiment of the present invention, which is mounted on a printed wiring board serving as a mother board.

As shown in FIG. 1, on the surface of the substrate (1) constituting the surface-mounting semiconductor package of the present invention, a recess (9) for mounting a semiconductor chip is formed by boring the central portion of the surface, A circuit pattern (3) is provided, and the circuit pattern (3) is formed by etching a metal foil provided on the surface of the substrate (1), or a circuit formed by other metal plating. There is no limitation, and the semiconductor chip mounted in the recess (9) is connected. Also,
A recess (9) for mounting a semiconductor chip on the surface of the substrate (1)
The shape and manufacturing method of the semiconductor are not particularly limited as long as the semiconductor chip can be mounted.

As the substrate (1) constituting the above-mentioned semiconductor package for surface mounting, an insulating resin substrate obtained by superposing a prepreg obtained by impregnating a base material with a resin varnish and drying, heat-pressing and curing the resin is applied. Alternatively, a ceramic insulating substrate such as alumina is used. The base material of the insulating resin substrate is not particularly limited, but an inorganic material such as glass fiber or aramid fiber is preferable because it is excellent in heat resistance and moisture resistance. Also, a cloth of organic fibers having excellent heat resistance or a mixture thereof can be used as a substrate. The resin varnish impregnating the base material, epoxy resin, polyimide resin, fluororesin, phenol resin,
Polyester resin, polyphenylene oxide resin, etc. may be used alone, modified, or a mixture.

The substrate (1) has a through-hole conductive path (2). The through-hole conductive path (2) is formed to connect the circuit pattern (3) on the upper surface and the external connection pad (6) on the lower surface, and a part of the circuit pattern (3) on the upper surface is formed. , The semiconductor chip is connected by wire bonding, and the other part is connected to the opening of the through-hole conductive path (2) to form a series of conductive circuits.

As shown in FIG. 3, the external connection pad (6) is formed on the lower surface of the substrate (1) constituting the surface mounting semiconductor package and is a through-hole conductive material penetrating from the upper surface of the substrate (1). It has an opening for the passage (2). In FIG. 3, the external connection pad (6) is disclosed as being rectangular, but the shape and size are not particularly limited, and a printed wiring board (4) for mounting a semiconductor package is provided.
The shape may vary depending on the external connection pad (5), and may be circular or polygonal as long as it has an opening for the through-hole conductive path (2) therein.

Next, a method for mounting and mounting the above surface mounting semiconductor package on a printed wiring board will be described.

The surface mounting semiconductor package shown in FIG. 1 described above is formed on the external connection pad (6) formed on the back surface of the surface mounting semiconductor package and on the upper surface of the printed wiring board (4) to be mounted. The formed external connection pads (5) are arranged on the upper surface of the printed wiring board (4) so that they coincide with each other, and the surface mounting semiconductor package and the printed wiring board (4) are connected by reflow soldering. The state of the surface-mounting semiconductor package that has been subjected to the reflow soldering is shown in a sectional view of the connected external connection pad (6). As shown in FIG. 4, the external connection of the printed wiring board (4) is performed. A solder bridge (7) is formed between the pad (6) for external connection and the pad (5) for external connection of the surface mounting semiconductor package, and a part of the solder is opened at the bottom of the through-hole conductive path (2). From the part, through-hole conductive path (2)
Solder rises along the inner wall of the metal toward the upper opening. This solder rise is much superior to that of the conventional LCC, because the external connection pads of the conventional LCC are semi-cylindrical electrode pads, and the through-hole conductive path (2) in the present invention is surrounded by the surrounding area. Is blocked,
This is because the capillary phenomenon remarkably occurs.

As described above, in the surface mounting semiconductor package according to the present invention, the external connection pad (6) formed on the back surface of the circuit pattern (3) on the surface of the substrate (1).
On the other hand, since the through-hole conductive path (2) is formed so as to penetrate through the external connection pad (6), the printed wiring board (4) on which the surface mounting semiconductor package is mounted is mounted.
On the other hand, the surface-mounting semiconductor package can be placed at an accurate position and soldered to surely connect and mount it.

[0016]

As described above, according to the semiconductor package for surface mounting of the present invention, unlike the leadless chip carrier, the semiconductor package is not half-cut, so that the plating on the wall surface of the through hole is peeled off or cracked. It is possible to supply a surface-mounting semiconductor package that does not cause such a problem, and when mounting on a mother board such as a printed wiring board, the surface-mounting semiconductor package and the printed wiring board are used for external connection. When reflow soldering is performed to connect the pads, soldering can be confirmed on the inner wall of the through-hole conductive path formed in the surface-mounting semiconductor package, and the physical and electrical connections have high reliability. Can be obtained.

[Brief description of drawings]

FIG. 1 is a perspective view of a surface-mounting semiconductor package according to an embodiment of the present invention.

FIG. 2 is a partially cutaway enlarged view of a surface mounting semiconductor package according to an embodiment of the present invention mounted on a printed wiring board.

FIG. 3 is a partially cutaway enlarged view of the lower surface of the surface-mounting semiconductor package according to an embodiment of the present invention.

FIG. 4 is a cross-sectional view of a through-hole conductive path of a surface mount semiconductor package according to an embodiment of the present invention.

FIG. 5 is a perspective view of a conventional surface mounting semiconductor package.

FIG. 6 is a partially cutaway enlarged view of a conventional surface mounting semiconductor package mounted on a printed wiring board.

[Explanation of symbols]

 1 Board 2 Through Hole Conductive Path 3 Circuit Pattern 4 Printed Wiring Board 5 Pad for External Connection 6 Pad for External Connection 7 Bridge of Solder 8 Electrode Pad 9 Recess

Claims (2)

[Claims] 1. A semiconductor chip is mounted on the front surface, a circuit pattern for connecting to the semiconductor chip is formed, an external connection pad is formed on the back surface, and a through-hole conductive path for conducting the circuit pattern on the front surface is formed in the external connection pad. A semiconductor package for surface mounting, which is characterized in that 2. When mounting the semiconductor package for surface mounting according to claim 1 on a mother board, pads for external connection are made to coincide with each other and soldered into the through-hole conductive paths to connect the circuits to each other. A method for mounting a surface-mounting semiconductor package on a motherboard, wherein the surface-mounting semiconductor package is mounted on a motherboard.