Active solid-state devices (e.g. – transistors – solid-state diode – Housing or package
Reexamination Certificate
2001-10-24
2004-01-20
Hu, Shouxiang (Department: 2811)
Active solid-state devices (e.g., transistors, solid-state diode
Housing or package
C257S666000, C257S676000, C257S784000, C257S787000
Reexamination Certificate
active
06680524
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a single-side-molded semiconductor device, which includes a wiring substrate having a ball grid array (BGA) arranged on the lower surface and a semiconductor chip molded with a resin encapsulant on the upper surface. The present invention also relates to a method for fabricating the device.
A semiconductor device of the BGA type has been available as a semiconductor device of an area array type. In the BGA type semiconductor device, a semiconductor chip is mounted and molded with a resin encapsulant on the upper surface of a substrate, and ball electrodes are attached to the lower surface thereof.
FIG. 21
is a plan view illustrating a known semiconductor device of the BGA type.
FIG. 22
is a bottom view illustrating the known BGA type semiconductor device.
FIG. 23
is a cross-sectional view thereof taken along the line XXIII—XXIII in FIG.
21
.
As shown in
FIGS. 21
,
22
and
23
, the known semiconductor device includes a wiring substrate
103
, wiring electrodes
101
, a semiconductor chip
104
, metal fine wires
105
, ball electrodes
102
and a resin encapsulant
106
. The wiring substrate
103
is made of an insulating resin. The wiring electrodes
101
are formed on the wiring substrate
103
. The semiconductor chip
104
is mounted on the wiring substrate
103
with the principal surface of the semiconductor chip
104
facing upward. Electrode pads (not shown) formed on the semiconductor chip
104
and the wiring electrodes
101
are electrically connected to each other with the metal fine wires
105
. The ball electrodes
102
are formed on the lower surface of the wiring substrate
103
. The resin encapsulant
106
is provided on the upper surface of the wiring substrate
103
. The semiconductor chip
104
, wiring electrodes
101
, metal fine wires
105
and the like are molded with the resin encapsulant
106
on the upper surface of the wiring substrate
103
. Although not shown in
FIG. 23
, external pad electrodes are formed on the lower surface of the wiring substrate
103
. The external pad electrodes are electrically connected to the wiring electrodes
101
through the substrate. The ball electrodes
102
are formed on the external pad electrodes.
The known semiconductor device has an approximately rectangular planar shape and the adjacent side faces thereof are perpendicular to each other. The outer shape has been determined so that the fabrication process of the semiconductor device can be simplified.
Also in the known semiconductor device, the ball electrodes
102
attached to the wiring substrate
103
are solder balls. The solder balls are attached to the wiring substrate
103
so that the overall semiconductor device can be highly reliably mounted and bonded onto a motherboard. In addition, as shown in
FIG. 22
, the ball electrodes
102
are arranged on the lower surface of the wiring substrate
103
in a latticed shape.
Next, the fabrication process of the known semiconductor device will be described.
FIGS. 24A and 24B
are respectively a plan view and a bottom view illustrating a known wiring substrate.
FIGS. 25A and 25B
are plan views illustrating a substrate preparation process step and a die bonding process step, respectively, in the fabrication process of the known semiconductor device.
FIGS. 26A and 26B
are plan views illustrating a wire bonding process step and a resin molding process step, respectively, in the fabrication process of the known semiconductor device.
FIG. 27
illustrates a cutting process step in the fabrication process of the known semiconductor device.
As shown in
FIGS. 24A and 24B
, the multiple wiring electrodes
101
are formed on the upper surface of the wiring substrate, and external pad electrodes
107
are formed on the lower surface of the wiring substrate. The external pad electrodes
107
are electrically connected to the wiring electrodes
101
through the substrate. The ball electrodes will be attached to the external pad electrodes
107
in the subsequent process step. The wiring substrate is a large-sized substrate on which multiple semiconductor chips will be mounted and which will be separated into individual semiconductor devices. The broken lines shown in
FIGS. 24A and 24B
are cutting lines, which will be used to separate the substrate into the individual semiconductor devices. Also, in each of the regions defined by the cutting lines in
FIG. 24
, a central area surrounded by each array of the wiring electrodes
101
is a chip mounting area where each of the semiconductor chips is mounted by bonding.
First, the wiring substrate with the structure shown in
FIGS. 24A and 24B
is prepared in the substrate preparation process step shown in FIG.
25
A.
Next, each of the semiconductor chips
104
is bonded, with an adhesive, onto each of the chip mounting areas of the wiring substrate in the die bonding process step shown in FIG.
25
B.
Subsequently, the electrode pads (not shown) formed on the principal surface of each of the semiconductor chips
104
and their associate wiring electrodes
101
formed on the wiring substrate are electrically connected to each other with the metal fine wires
105
in the wire bonding process step shown in FIG.
26
A.
Then, the members disposed on the upper surface of the wiring substrate, e.g., the semiconductor chips
104
, wiring electrodes
101
, metal fine wires
105
, are transfer-molded with the resin encapsulant
106
in the resin molding process step shown in FIG.
26
B. The wiring electrodes
101
and semiconductor chips
104
are indicated by the broken lines in FIG.
26
B. However, the metal fine wires
105
are not shown in the figure.
Next, in the cutting process step shown in
FIG. 27
, the wiring substrate having the upper surface entirely molded with the resin encapsulant
106
is cut along the cutting lines using a rotary blade, thereby obtaining individual semiconductor devices
108
of the BGA type. Hence, the semiconductor devices
108
with the structure shown in
FIGS. 22 and 23
can be obtained.
In this example, the wiring substrate is cut, using the rotary blade, along the cutting lines indicated by the broken lines shown in
FIGS. 24A and 24B
. In this manner, the individual semiconductor devices can be obtained accurately. Normally, the separation by a rotary blade is performed using a dicing machine generally used in the fabrication process of a semiconductor device. Also, in the cutting process step, the wiring substrate is cut from either the lower surface or the resin encapsulant
106
side thereof.
In the subsequent process step, which is not shown, in each of the individual semiconductor devices
108
, a solder ball is attached to each of the external pad electrodes
107
formed on the lower surface of the wiring substrate
103
. In this manner, the multiple ball electrodes are formed and will be used as external terminals.
The process steps for fabricating the known semiconductor device have been performed in the above-described manner, i.e., the large-sized substrate on which the multiple semiconductor chips can be mounted is used. Then, a large number of semiconductor chips are mounted on the substrate, the associate members are electrically connected via the metal fine wires, and the members disposed on the upper surface of the wiring substrate are molded with the resin encapsulant. Thereafter, the wiring substrate is cut using the rotary blade and separated into the individual semiconductor devices.
However, the known semiconductor device has drawbacks, i.e., the humidity- and stress- resistance of the semiconductor device is low. This might be because neither the semiconductor chip
104
and resin encapsulant
106
nor the wiring substrate
103
and resin encapsulant
106
are sufficiently secured to each other.
For this reason, it is difficult to increase the reliability of the semiconductor device. Particularly, it is important to obtain the reliability of semiconductor devices used in small electronic units such as mobile phones.
SUMMARY OF THE INVENTION
An object of t
Fujimoto Hiroaki
Fukuda Toshiyuki
Minamio Masanori
Nomura Toru
Sahara Ryuichi
Hu Shouxiang
Matsushita Electric - Industrial Co., Ltd.
Nixon & Peabody LLP
Studebaker Donald R.
Vu Quang
LandOfFree
Semiconductor device and method for fabricating the same does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Semiconductor device and method for fabricating the same, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Semiconductor device and method for fabricating the same will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3243459