Plastic and nonmetallic article shaping or treating: processes – With step of cleaning – polishing – or preconditioning...
Reexamination Certificate
1999-05-04
2001-05-08
Tentoni, Leo B. (Department: 1732)
Plastic and nonmetallic article shaping or treating: processes
With step of cleaning, polishing, or preconditioning...
C264S083000, C264S322000, C264S337000, C264S338000, C427S135000, C427S248100
Reexamination Certificate
active
06228294
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a method for compression molding.
2. Background of the Related Art
Compression molding process has been previously used for processing high polymer material. The compression molding method is performed by making a mold of a desired pattern of metal material and then compressing a high polymer material within the mold. The high polymer material should have flowability because it should enter and fill the mold by pressure applied to the high polymer material. To ensure such flowability, a transfer path of both the mold and the high polymer material is maintained at high temperature above a glass transition temperature of the high polymer material. Once the high polymer material conforms to the mold of the desired pattern, it is cooled for a certain amount of time to eliminate flowability of the high polymer. The high polymer material is then solidified, and the mold is removed to produce the solid high polymer product having the mold pattern.
FIG. 1
is a schematic view of a related art compression molding press. The related art compression molding press will now be described.
The related art compression molding press includes a press support
1
, a plate induction axis
2
, an upper press plate
6
, and a lower press plate
5
. The press support
1
is located at the bottom of the press, and the press plate induction axis
2
is fixed to both sides of the press support
1
. The upper press plate
6
and the lower press plate
5
are fixed on the press plate induction axis
2
to be opposed each other. The upper press plate
6
is fixed on the induction axis
2
and the lower press plate
5
is fixed to ascend and descend along the induction axis
2
. The upper and lower press plates
5
and
6
also have the capability for internal temperature adjustment.
A mold support
8
a
to which a mold
9
is fixed is located on the bottom of the upper press plate
6
. A test piece support
8
b
is fixed on the lower press plate
5
to support a test piece
10
.
A pressure device
3
is fixed on the center of the upper side of the press support
1
to allow a flange
12
to reciprocate the lower press plate
5
relative to the fixed upper press plate. A pressure gauge is attached to one side of the pressure device
3
to check pressure when operating the pressure device
3
.
A related art compression molding method will now be described. The related art compression molding method is performed using the related art compression molding press as shown in FIG.
1
.
FIGS. 2
a
to
2
c
are sectional views illustrating the related art compression molding method.
As shown in
FIG. 2
a,
the test piece
10
on which a high polymer thin film
11
is deposited is positioned on the test piece support
8
b.
The mold
9
with a pattern of dots or lines of about 25 nm is positioned on the mold support
8
a.
Polymethylmethacrylate (PMMA) polymer is used as the high polymer thin film
11
.
The mold
9
and the test piece
10
(i.e., a resist) are heated at a temperature (about 200° C.) above the glass transition temperature. As shown in
FIG. 2
b
, the mold
9
and the test piece
10
are compressed so that the pattern of the mold
9
can be molded on the high polymer thin film
11
of the test piece
10
. When the temperature of the mold
9
and the test piece
10
are decreased to reduce the PMMA below the glass transition temperature of the PMMA, the mold
9
is separated from the test piece
10
. As shown in
FIG. 2
c
, the molded high polymer thin film
11
is etched by anisotropic etching to form a final pattern.
In another related art compression molding process, a high polymer material is heated to a high temperature above its glass transition temperature. Under these circumstances, the high polymer material contacts an inner wall of a mold and adheres to a surface of the inner wall of the mold. As a result, the high polymer material is not likely to be separated from the inner wall of the mold even after this process is completed. To prevent this problem, in this related art compression molding process, a mold release agent is applied to the surface of the inner wall of the mold. Chemical materials such as organosilicon compounds are used as the related art mold release agent.
As described above, the related art compression molding methods have various disadvantages. When the dimension of the pattern is large, an adhesion property at the interface between a mold surface and a high polymer material can be removed using the organosilicon mold release agent. Disadvantageously, if the mold release agent is applied to the surface of the mold embossed or engraved with a pattern having fine granularity of 1 micron or less, the mold release agent is thicker than the dimension of the pattern so that the fine pattern on the mold becomes covered by the mold release agent. As a result, the desired fine pattern cannot be imprinted. Further, even though the pattern is transferred to the substrate, the pattern is not exactly imprinted at a desired position and dimension because of the thick mold release agent that exists on the mold surface. In addition, if related art compression molding methods are performed at high pressure, the substrate to which the pattern is to be transferred and the mold substrate may physically be damaged, so that the pattern fails to be transferred to the substrate. Finally, when the pattern transferred to the surface of the high polymer is varied or distorted with a pattern dimensioned in the range of about 1 micron, there exists no technology to remove this defect or to adjust the dimension of the pattern at such dimensions when the pattern transfer has already completed by compression molding.
The above references are incorporated by reference herein where appropriate for appropriate teachings of additional or alternative details, features and/or technical background.
SUMMARY OF THE INVENTION
An object of the present invention is directed to a compression molding method that substantially obviates one or more of the problems caused by limitations and disadvantages of the related art.
Another object of the present invention is to provide a compression molding method that obtains a fine pattern for a molded high polymer material that increases the pattern accuracy.
Another object of the present invention is to provide a compression molding method that reduces or removes adhesion on the interface between a mold substrate patterned with a pattern and a high polymer material to be imprinted with the pattern from the mold substrate.
Another object of the present invention is to provide a compression molding method that removes or reduces an adhesion property between a mold substrate and a high polymer material that is to be imprinted with a high granularity pattern to obtain a pattern having increased accuracy for application in fabrication processes of semiconductor and electronic products.
To achieve at least these objects and other advantages in a whole or in parts and in accordance with the purpose of the present invention, as embodied and broadly described, a compression molding method using a mold substrate patterned with a fine pattern for transfer to a high polymer material test piece includes the steps of heating any selected one of the mold substrate and the high polymer material compression-molding the mold substrate and the high polymer material and separating the high polymer material test piece and the mold substrate from each other after cooling the heated one of the mold substrate and the high polymer material for a prescribed time.
To further achieve at least the above objects in a whole or in parts in accordance with the present invention, a compression molding method includes fluorine-terminating a surface of the mold, compression-molding the mold and the high polymer material test piece, and separating the high polymer material test piece and the mold from each other.
To further achieve at least the above objects in a whole or in parts in accordance with the present invention,
Kang Dal Young
Lee Hong Hee
Fleshner & Kim LLP
Hyundai Electronics Industries Co,. Ltd.
Tentoni Leo B.
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