Substrate structure of BGA semiconductor package

Details Substrate structure of BGA semiconductor package Substrate structure of BGA semiconductor package

1999-06-23

2001-03-13

Thomas, Tom (Department: 2811)

Active solid-state devices (e.g., transistors, solid-state diode

Housing or package

Insulating material

C257S684000, C257S702000, C257S723000, C257S778000, C257S782000, C257S738000, C257S780000, C257S784000, C257S787000, C257S783000, C438S125000, C438S126000

Reexamination Certificate

active

06201299

ABSTRACT:

BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates generally to the substrate structure of a BGA semiconductor package, and more particularly to a plurality of dispensing holes which are provided adjacent to the two ends of a hole in the substrate.
2. Description of the Related Art
As the function of the IC (“Integrated Circuit”) becomes complicated, the BGA semiconductor package, the package technology of high-finger density, is adapted for use in manufacturing ULSI (Ultra-Large Scale Integration) in submicro scale. The BGA semiconductor package is a method of packaging in accordance with the requirement of high finger density.
In the BGA semiconductor package, an adhesive layer of elastomer is attached to the substrate, and then a chip is adhered to the adhesive layer on the substrate. Wires electrically connect the chip and the substrate to form a closed loop. After the wire-bonding process, liquified encapsulant material is dispensed over the wire-bonding area of the chip or around the chip to form an encapsulant. The dispensing process has two steps. In the first step, the liquified encapsulant material is dispensed over the wire bonding-area of the chip to form a first encapsulant on one surface of the substrate, then the substrate is placed in an oven for curing process. The substrate is turned over for the next step of processing. In the second step, the liquified encapsulant material is dispensed around the chip to form a second encapsulant on the other surface of the substrate. Then the substrate is placed in an oven for curing process. A plurality of solder balls is soldered onto the substrate to electrically connect the chip and form the fingers of the chip. At the end, the semiconductor device is cut to form an IC device in the cutting process. The dispensing process and the curing process take a long time, and the processing steps need to be reduced. In addition, during the curing process in the first step, the substrate has warpage under different CTE (“coefficient of thermal expansion”) of the substrate and the encapsulant; thus this art has the disadvantage of warpage of the substrate during manufacture.
Referring to
FIG. 1
, the conventional package has a substrate strip
100
providing a plurality of substrates
110
which have a hole therein. A chip
120
is adhesively attached to the substrate
110
by an adhesive layer (not shown). For carrying and packaging, the substrate has a plurality of guide holes
101
, a plurality of position holes
102
and a plurality of separation holes
103
.
Referring to
FIG. 2
, a chip
120
is adhesively attached to the surface of the substrate
110
thereon by an adhesive layer
115
. A first encapsulant
112
covers area on the side of chip
120
. This area is defined as the upper surface of substrate
100
adjacent to chip
120
. The first encapsulant
112
prevents moisture from the environment entering to the package. A second encapsulant
113
covers the area of wires
116
on another surface of substrate
110
. Furthermore, a plurality of solder balls
114
is soldered on the same surface as encapsulant
113
to connect to chip
120
and form the fingers of chip
120
. However, the liquified encapsulant material of the first encapsulant
112
and the second encapsulant
113
of substrate
110
need to be dispensed onto two surfaces of substrate
110
in two separate steps. This has disadvantage of increasing the complexity of manufacture.
The present invention intends to provide a substrate that has a main hole adjacent to the dispensing holes in such a way as to mitigate and overcome the above problem.
SUMMARY OF THE INVENTION
The primary objective of this invention is to provide a substrate structure of a BGA semiconductor package which includes a substrate that has a main hole whose two ends are adjacent to the dispensing holes on upper surface of the substrate. Thus, an encapsulant is formed on two surfaces of the substrate at the same time by means of liquified encapsulant material that flows through the dispensing hole from the upper surface to the lower surface.
The present invention is the substrate structure of a BGA semiconductor package, and the substrate structure mainly comprises a plurality of substrate units and a plurality of dispensing holes thereon. A main hole is provided on the surface of the substrate unit. The two ends of the main holes are adjacent to the dispensing hole for dispensation of the liquified encapsulant material to form a semiconductor package. The semiconductor package mainly comprises a chip, a substrate and an encapsulant. The chip is adhesively attached to the substrate, and the encapsulant covers the side area of the chip. Then the encapsulant flows from the upper surface of the substrate to the lower surface to cover wire areas by means of the liquified encapsulant material that flows through the dispensing hole from the upper surface of the substrate to the lower surface.
Other objectives, advantages and novel features of the invention will become more apparent from the following detailed description and the accompanying drawings.


REFERENCES:
patent: 5585666 (1996-12-01), Imamura
patent: 5614760 (1997-03-01), Osono et al.
patent: 6013946 (2000-01-01), Lee et al.
patent: 6048755 (2000-04-01), Jiang et al.

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