Stock material or miscellaneous articles – Structurally defined web or sheet – Continuous and nonuniform or irregular surface on layer or...
Reexamination Certificate
2001-08-15
2004-10-12
Loney, Donald J. (Department: 1772)
Stock material or miscellaneous articles
Structurally defined web or sheet
Continuous and nonuniform or irregular surface on layer or...
C428S172000, C428S537500, C249S187100
Reexamination Certificate
active
06803089
ABSTRACT:
FIELD OF THE INVENTION
The invention relates to a cleaning substrate for cleaning and regenerating a mold, and more particularly, to a cleaning substrate for cleaning a mold of a semiconductor package that can save the amount of the usage of the cleaning compound without changing the facilities of the original fabrication process.
BACKGROUND OF THE INVENTION
During the encapsulating process by making use of the mold for molding the encapsulant of thermosetting resin, the mold releasing agent contained in the encapsulant of thermosetting resin can seep into the inner surface of the mold in order to release the mold. However, the mold-releasing characteristic of the molding parts will be deteriorated and the molding parts will be damaged cosmetically resulting from the continuously repeating the encapsulating process. Consequently, the material layer is contaminated and the mold releasing agent become less effective.
To resolve the above-mentioned problems, cleaning work must be undertaken to remove the contaminated material layer that makes the mold-releasing agent ineffective. For example, an encapsulant made of thermosetting melamine resin is put in the mold so as to make the contaminated material, which is positioned on the inner surface of the mold, integrally form and solidify in order to be removed, thereby, the inner surface of the mold is cleaned.
FIG.
1
and
FIG. 2
disclose a conventional semiconductor mold. As shown in FIG.
1
and
FIG. 2
, the semiconductor mold
10
has a pot
11
for storing encapsulant. The pot
11
is connected to a mold cavity
14
through a runner
12
and a gate
13
where the mold cavity
14
is employed for placing semiconductor chip (not shown). When packaging a semiconductor chip, a plunger
15
is employed to press downward so as to compress the encapsulant that is liquidized to flow through the runner
12
and the gate
13
, and then fill the mold cavity
14
so as to encapsulate the semiconductor chip. Thereafter, the mold
10
is opened and the molded products are taken out after the encapsulant material is hardened.
However, after the above-mentioned steps are continuously performed, a contaminated material layer is generated on the inner surface of the mold
10
. Especially, the contaminated material layer on the inner surface of the mold cavity
14
will cosmetically damage the molded products. Therefore, it is necessary to clean the contaminated material layer of the mold
10
. As shown in
FIG. 2
, when cleaning the mold
10
, a cleaning substrate
20
is put into the mold
10
, and a cleaning compound is injected into the mold cavity
14
. As the cleaning compound is solidified, it will integrally form with the contaminated material layer on the inner surface of the mold cavity
14
and the cleaning substrate to become a plastic mold which is then taken out of the mold cavity
14
. The inner surface of the mold will be entirely cleaned after repeating the above-mentioned action for around 10 to 15 times.
It is noted that the cleaning substrate
20
is generally designed in the shape of a plate that can not effectively reduce the volume of the mold cavity
14
such that it takes several times for mold injecting to fill the mold cavity
14
of the mold
10
. As a result, it unnecessarily wastes the material of the cleaning compound.
In the light of the above-mentioned disadvantages, it is necessary to provide a cleaning substrate for cleaning the mold of the semiconductor package that can save the amount of the usage of the cleaning compound without changing the facilities of the original fabrication process.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a cleaning substrate for cleaning the mold of the semiconductor package that can save the amount of the usage of the cleaning compound.
To achieve the above object, the present invention provides a cleaning substrate for cleaning and regenerating a mold. A protrusion provided on the substrate can substantially match with and be contained within the edges of a mold cavity of the mold when the cleaning substrate is placed in the mold while the mold is contaminated after repeatedly packaging the semiconductor device.
In another aspect of the cleaning substrate according to the present invention, the profile of the protrusion is corresponding to the edges of the mold cavity.
In one other aspect of the cleaning substrate according to the present invention, the cleaning substrate is made of paper.
In addition, a cleaning method provided by the present invention for cleaning a mold includes the following steps:
(a) providing a mold having at least a mold cavity;
(b) placing a cleaning substrate in the mold cavity wherein the cleaning substrate has at least a first protrusion that can substantially match and be contained within the edges of the mold cavity;
(c) injecting a cleaning compound into the mold cavity of the mold;
(d) hardening the cleaning compound such that the cleaning compound is integrally formed with the cleaning substrate to become a molding product; and
(e) taking the molding product out of the mold cavity by opening the mold.
According to the cleaning substrate of the present invention for cleaning semiconductor package, when cleaning the mold, a cleaning substrate is put into the mold. The multiplicity of protrusions of the cleaning substrate can be substantially contained within the edges of the multiplicity of mold cavities of the mold. Then, a cleaning compound is injected into the mold cavity. The cleaning substrate can reduce the amount of usage for mold injection since the protrusions are provided on the cleaning substrate to reduce the volume of the cavity.
REFERENCES:
patent: 3130412 (1964-04-01), Fox et al.
patent: 3575764 (1971-04-01), McFarren
patent: 4935175 (1990-06-01), Kitaura et al.
patent: 5366785 (1994-11-01), Sawdai
patent: 5443889 (1995-08-01), Ruppel et al.
patent: 6077360 (2000-06-01), Takashima
Advanced Semiconductor Engineering Inc.
Loney Donald J.
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