Plastic article or earthenware shaping or treating: apparatus – With interposed non-adhering web or sheet type parting means
Reexamination Certificate
1999-05-19
2001-05-01
Davis, Robert (Department: 1722)
Plastic article or earthenware shaping or treating: apparatus
With interposed non-adhering web or sheet type parting means
C425S116000, C425S127000, C425S544000
Reexamination Certificate
active
06224360
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a resin sealing method and device for chip size packages.
2. Description of the Related Art
The chip size packages (hereinafer referred to as “CSP”) are formed substantially in the same size as a semiconductor chip, and as one of the CSPs, there is an SON (small outline nonlead) package.
FIGS. 1 and 2
are a sectional view and a bottom view of the CSP, particularly SON, respectively. In
FIG. 1
, reference numeral
10
denotes a semiconductor chip;
112
denotes a die pad; and
114
is leads for electrically connecting the semiconductor chip
10
and a package substrate. Each of the leads
114
is formed as a bonding part
114
a
joined to the semiconductor chip
10
at a center thereof with the surface of a joint electrically connected to an electrode of the semiconductor chip
10
by wire bonding. An outer portion of each of the bonding parts
114
a
is formed as a connection part
114
b
slightly floating up from the chip face and extending in parallel with the chip face for connection to the package substrate.
Each of the connection parts
114
b
is placed in the chip face of the semiconductor chip
10
and the whole package is formed substantially in a chip size. Reference numeral
116
denotes bonding wires for electrically connecting the electrode of the semiconductor chip
10
and each of the leads
114
. Reference numeral
18
denotes a sealing resin for sealing the joint faces to the leads
114
of the semiconductor chip
10
. The sealing resin
18
seals the wiring bonding portions of the semiconductor chip
10
and the leads
114
and also supports the connection parts
114
b
, of the leads
114
at predetermined positions.
The connection part
114
b
of each the respective lead
114
is exposed to the outer face of the sealing resin
18
for connection to the package substrate by soldering, etc. In the example shown in
FIGS. 1 and 2
, the connection parts
114
b
are placed in parallel with a given spacing on two opposed sides on the outer face of the sealing resin
18
. They are formed on a flat face so that they can be connected to the connection parts of the package substrate by soldering, etc.
If a normal transfer mold method is used to seal the joint faces of the semiconductor chip
10
and the leads
114
with a resin in a manufacturing process of CSPs as described above, resin fins may occur on the surfaces of the leads
114
. Thus, because the normal transfer mold method cannot be used and hitherto, a potting method has been used to seal with a resin. Since the CSP has a large number of leads
114
placed in parallel with the chip face, it is placed in portrait orientation and a potting resin is injected.
However, the potting method involves the following problems: It takes much time until the resin hardens, and mass productivity is poor. Air is easily caught in the resin at the potting time, whereby voids easily occur. Close adherence of the resin to the semiconductor chip
10
is not necessarily sufficient. The potting method is lower in resin molding accuracy than the resin sealing method using a transfer mold. Voids occurring in the package cause cracks to occur due to heat at a curing process. After packaging, temperature rise and drop in the external environment act repeatedly on the package, thereby breaking the package or short-circuiting the wiring pattern.
FIGS. 3A
to
3
D show other product examples of the CSP. For a product shown in
FIG. 3A
, a wiring pattern
212
is provided via an electric insulating layer
211
on a face where surface electrodes of a semiconductor chip
10
are placed, and solder balls
214
are joined as external connection pins. The solder balls
214
are connected to one end of the wiring pattern
212
and the other end of the wiring pattern
212
is extended like leads from the periphery of the electric insulating layer
211
to the outside and are bonded to the surface electrodes
216
of the semiconductor chip
10
.
A sealing resin
18
of the wiring pattern
212
is bonded to the surface electrodes
216
. Hitherto, the wiring pattern
212
of the portion bonded to the surface electrodes
216
has been sealed by potting. The reason why it has been sealed by potting is as follows: Since the wiring pattern
212
in the chip size package is supported via the electric insulating layer
211
on the semiconductor chip
10
, if the wiring pattern
212
is sealed with a resin by a normal transfer mold method, a molded article (an object to be molded) cannot reliably be pressed and a resin fin occurs in an unnecessary part and when a runner is peeled off or a gate is broken after the wiring pattern
212
is sealed with the resin, the wiring pattern may be damaged.
FIG. 3B
shows a structure in which a semiconductor chip
10
is housed in a ring
120
shaped like a rectangular frame and
FIG. 3C
shows a structure in which a semiconductor chip
1
(is housed in a can
222
as other product examples of CSPs.
FIG. 3D
shows a fan-in/fan-out type product wherein the semiconductor chip
10
is supported on a package substrate
224
formed with a recess for housing the semiconductor chip
10
and a wiring pattern
212
is provided in each of an inner area and an outer area of the semiconductor chip
10
and external connection pins are bonded. For every example shown in
FIGS. 3B
,
3
C and
3
D, the wiring pattern
212
of the portion bonded to the surface electrodes
216
of the semiconductor chip
10
is sealed by potting.
SUMMARY OF THE INVENTION
This invention has been made in view of the above circumstances, and therefore an object of the invention is to provide a resin sealing method and device for CSPs which can reliably seal packages with a resin without causing resin fins to occur, enable easy mass production of CSPs, and can provide high-reliability CSPs.
Another object of the invention is to provide a resin sealing method and device for chip size packages for enabling CSPs to be sealed with a resin by a transfer mold method, thereby improving the molding accuracy of the packages and preventing voids from occurring in the package, thereby easily manufacturing high-reliability chip size packages.
To achieve the above objects, according to a first aspect of the invention, there is provided a resin sealing method of a CSP electrically connected to electrodes of a semiconductor chip in the chip face of the semiconductor chip with one end of leads joined and the other end thereof exposed to the outer face of a sealing resin for sealing the chip face as connection parts to a package substrate, etc., the method comprising the steps of using a transfer mold formed with a cavity recess in which the molded article comprising the semiconductor chip joined to the leads is set, setting the molded article in the cavity recess with the transfer mold face containing the cavity recess of the transfer mold covered with a release film having required flexibility and heat; resistance, clamping the molded article with the transfer mold face of the other transfer mold mated with that transfer mold with a release film, and filling the cavity with a resin for sealing the package with the resin.
The plane portion of the cavity recess in which the molded article is housed is varied in size. When the molded article is set in the cavity recess, the plane portion is set larger than the outside dimensions of the semiconductor chip. After the molded article is set in the cavity recess, the size of the plane portion of the cavity recess is reduced matching the outside dimensions of the molded article and the molded article is clamped from the side face for resin sealing.
Of the transfer mold parts making up the four side faces of the cavity recess, the transfer mold part formed with the gate is made a fixed mold part and the remaining transfer mold parts are made moving mold parts for varying the size of the plane portion of the cavity recess.
According to the invention, there is provided a resin sealing system of a CSP electrically connected to electrodes of a semicond
APIC Yamada Corporation
Davis Robert
Sughrue Mion Zinn Macpeak & Seas, PLLC
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