Semiconductor device manufacturing: process – Packaging or treatment of packaged semiconductor
Reexamination Certificate
2000-05-02
2001-11-20
Smith, Matthew (Department: 2825)
Semiconductor device manufacturing: process
Packaging or treatment of packaged semiconductor
C438S123000, C438S111000, C438S455000
Reexamination Certificate
active
06319749
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a lead frame having a wiring film obtained by laminating an insulating film on a lead pattern, a semiconductor package having a super multiple pin structure in which a semiconductor element (chip) is joined to the lead frame, and a method for manufacturing the lead frame and the semiconductor package.
The following semiconductor device is proposed by the applicant of this application. That is, a lead frame in which leads to be connected to electrodes of a semiconductor element at one end portions thereof are formed on one surface side of an insulating film, and further the external terminals connected to the other end portions of the leads are formed on the other surface side of the insulating film, is mounted on the semiconductor element, and a reinforcing outer ring surrounding the semiconductor element is formed at the outside of the semiconductor element.
However, in such a semiconductor device, it is indispensable to fill sealing agent in a gap between the outer ring and the semiconductor element after the outer ring surrounding the semiconductor element is disposed and the outer ring and the semiconductor element are positioned. The necessity of the positioning process obstructs the reduction in the number of fabrication processes of the semiconductor device. It is needless to say that this is a cause to obstruct the cost-down of the semiconductor device.
A semiconductor device which can solve the above problem has been proposed.
FIG. 1
shows such a semiconductor device, wherein
FIG. 1A
is a plan view and
FIG. 1B
is an enlarged cross-sectional view which is taken along B—B line.
In
FIGS. 1A and 1B
,
1
represents a lead frame (film circuit), and reference numeral
2
represents an insulating film which serves as a base of the lead frame
1
.
3
represents leads (wiring films) which are formed at one side (lower side) of the insulating film
2
, and the tip portions
3
a
thereof are connected to electrode pads
5
of a semiconductor element
4
. The leads
3
are formed by forming metal such as copper, nickel or the like by using as a mask a resist having a negative pattern to a pattern to be formed.
Reference numeral
6
represents ball-shaped outer terminals formed on the end portions
3
b
of the leads
3
which are located at the opposite side to the side which is connected to the electrode pads
5
of the semiconductor element
4
, and the outer terminals are formed of nickel and soldering or gold. They are formed on a plane which is opposite to the semiconductor element side of the base (insulating film)
2
, and connected to the end portions
3
b
of the leads
3
through holes of the base
2
.
Reference numeral
8
represents a reinforcing outer ring which surrounds the semiconductor element
4
, and it is formed integrally with the outside of the main portion of the lead frame through suspending portions
10
. It has a laminate structure comprising copper, aluminum, copper, nickel or the like. The suspending portions
10
are formed of the same layers as the leads
3
, and thus they are formed of copper or nickel, for example.
According to the above lead frame, as shown in
FIG. 1A
, the outer ring
8
is formed integrally with the outer portion of the main portion
15
of the lead frame through the suspending portions
10
. Therefore, as shown in
FIG. 1B
, the ring
8
can be positioned to the semiconductor element
4
by merely mounting the lead frame
1
on the semiconductor element
4
. Accordingly, no special process is needed to dispose the ring
8
in a predetermined positional relationship with the semiconductor element
4
.
Accordingly, the number of fabrication steps of the semiconductor device can be reduced, and thus the manufacturing cost of the semiconductor device can be reduced.
In the case of the lead frame described above, the width of the suspending portions is narrow, and for example, it is equal to about 18 to 25 micrometers. Therefore, there is a problem that it is likely to be deformed under application of only a small impact during transportation or fabrication process because the mechanical strength thereof is low.
When the suspending portions of the lead frame are likely to be deformed as described above, the suspending portions are broken in the worst case and the circuit portion falls off, so that the yield is lowered. Further, when the suspending portions of the lead frame are likely to be deformed, the position precision between the circuit portion and the outer ring is lowered, so that a problem occurs in the fabrication process.
FIG. 2
shows a semiconductor package which can be mounted on a print wiring plate or the like through an organic substrate having external connection terminals such as solder balls or the like.
In
FIG. 2
, a semiconductor chip
51
is mounted on the surface of a multilayered organic wiring board
50
which is formed of organic material and comprises two to six layers. The electrode pads
50
of the semiconductor chip
51
and wiring films
52
are connected to each other by a wire bonding method using gold wires
53
or the like.
Solder balls (external connection terminals)
55
which are electrically connected via through-holes
54
to the wiring films
52
on the obverse surface are provided on the back surface of the multilayered organic wiring substrate
50
, and the solder balls
55
are exposed from the open portion of a solder resist film
56
to the outside. The semiconductor chip
51
as well as the gold wires
53
is sealed by sealing resin
57
.
In the semiconductor package
58
thus constructed, the solder balls
55
formed on the back surface are connected to the print wiring plate
59
. The multilayered organic wiring board
50
is usually called as Ball Grid Array (BGA) because a number of solder balls
55
are arranged in a grid form, and the semiconductor package
58
using the multilayered organic wiring board
50
is called as BGA package.
However, in the above-described semiconductor package
58
, the electrode pads of the semiconductor chip
51
and the wiring film
52
of the multilayered organic wiring substrate
50
are connected to each other by the wire bonding, and thus there is a limitation in the shortening of the wiring pitch. In other cases, for example, in a semiconductor package which is called as TCP (Table Carrier Package), a copper foil which is attached onto an insulating film base is etched to form leads, and thus there is such restriction that the leads are narrowed due to side etching. Therefore, there is also a limitation in the multiple-pin design.
SUMMARY OF THE INVENTION
The present invention has been implemented to solve the above problems of the prior arts, and has a first object to provide a novel lead frame which can prevent the suspending portions from being deformed by merely improving the structure of the suspending portions, and a method of manufacturing the lead frame.
A second object of the present invention is to enhance the reliability of a semiconductor package by preventing the breaking and failure of leads due to environmental stress.
A third object of the present invention is to provide a semiconductor package which can facilitate the resin injection from the back surface of the chip even when the size of the outer ring is small.
A fourth object of the present invention is to provide a semiconductor package in which the chip size can be reduced without reducing the number of external connection terminals.
In order to attain the above objects, according to a first aspect of the present invention, a lead frame is characterized in that reinforcing portions for reinforcing the suspending portions are provided on the suspending portions which support a ring surrounding a semiconductor element.
Accordingly, according to the lead frame described above, the suspending portions are reinforced because the reinforcing portions are provided on the suspending portions, so that the suspending portions can be prevented from being deformed.
Accordingly, there is no possibility that the susp
Ito Makoto
Makino Haruhiko
Osawa Kenji
Sato Kazuhiro
Shigeta Hiroyuki
Luu Chuong
Smith Matthew
Sonnenschein Nath & Rosenthal
Sony Corporation
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