Semiconductor device manufacturing: process – Making device or circuit emissive of nonelectrical signal – Including integrally formed optical element
Reexamination Certificate
2002-06-28
2004-12-28
Picardat, Kevin M. (Department: 2822)
Semiconductor device manufacturing: process
Making device or circuit emissive of nonelectrical signal
Including integrally formed optical element
C438S778000, C438S780000
Reexamination Certificate
active
06835583
ABSTRACT:
The present invention claims the benefit of Korean Patent Application No 67236/2001 filled in Korea on Oct. 30, 2001, which is hereby incorporated by reference.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a printing system and method used for fabricating a liquid crystal display device, and more particularly, to a printing system and printing method for fabricating a thin film transistor, a color filter, and a black matrix of a liquid crystal display device
2. Description of the Related Art
In general, cathode ray tube (CRT) monitors are commonly used to display information on a computer displays and televisions because of the CRT monitor's superior picture quality and image brightness. However, as demand for larger displays increases, the size of the CRT monitors also increases. Accordingly, the overall size of the CRT monitor eventually increases to a point where it's size is too large to efficiently display image data. In addition, mobility of the CRT monitor decreases as overall weight of the CRT monitor increases.
Presently, flat type display devices, such as liquid crystal displays (LCD's), plasma display panel (PDP) displays, organic electro luminescence (EL) displays, light emitting diodes (LEDs), and field emission displays have gained in popularity. Among the different flat panel display devices, liquid crystal display (LCD) devices have been developed as monitors for laptop and desktop computers because of their low power consumption
FIG. 1
is a cross-sectional view of an LCD device panel according to the conventional art. In
FIG. 1
, the LCD device panel is formed of a lower substrate and an upper substrate. The upper substrate includes a glass substrate
10
having a color filter layer
11
, a black matrix
12
, an orientation layer
14
, and a common electrode
13
. Both the black matrix
12
and the color filter layer
11
are formed on the glass substrate
10
, wherein the black matrix
12
is disposed between adjacent color filter layers
11
. The color filter layer
11
includes a resin film containing dye or three basic colors of red, green, and blue or a pigment thereof. An overcoat film (not shown) is provided for smoothing the color filter layer
11
and improving an adhesive force with the common electrode
13
, which is commonly formed of a transparent conductive material, such as indium tin oxide (ITO). The orientation layer
14
aligns a liquid crystal material formed between the upper and lower substrates.
In
FIG. 1
, the lower substrate includes a glass substrate
10
having a thin film transistor (TFT) formed thereon, a protection film
20
, a pixel electrode
21
, and an orientation layer
14
The TFT includes a gate electrode
15
, an active layer
16
, a source electrode
18
, and a drain electrode
19
. The gate electrode
15
is formed on the glass substrate
10
with a gate insulating layer
17
formed on the gate electrode
15
and the glass substrate
10
. The active layer
16
includes a semiconductor layer
16
a
formed by depositing an amorphous silicon (a-Si) and a n+ doped ohmic contact layer
16
b
at opposing upper portions of the semiconductor layer
16
a
. The protection film
20
is formed to cover the TFT and the gate insulating film
17
. The pixel electrode
21
is formed on the protection film
20
and is formed of a transparent conductive material, such ITO The orientation layer
14
is formed on the pixel electrode
21
and the protection film
20
. Polarizing films
22
are disposed on the outside surfaces of the upper and lower substrate respectively
In
FIG. 1
, light transmittance through the liquid crystal layer formed between the upper and lower substrates is controlled by application of an electric potential on the common electrode
13
and the pixel electrode
21
. The common electrode
13
commonly receives a constant potential, whereas the pixel electrode
21
receives a data signal to generate the electric field. The pixel electrode
21
receives the data signal when the TFT is turned on. Specifically, a data signal is supplied to the source electrode
18
of the TFT and is transmitted via the active layer
16
a
through the ohmic contact layer
16
b
when the gate electrode
15
is enabled by receiving a scan signal. Accordingly, the data signal is transmitted to the drain electrode
19
and applied to the pixel electrode
21
, thereby generating the electric field in combination with the common electrode
13
and controlling the light transmitted through the liquid crystal layer.
Fabrication of the LCD device commonly includes a thin film deposition process, a photolithographic process, and an etching process that are repeatedly performed. Moreover, fabrication of the TFT, the color filter layer
11
, and the black matrix
12
includes sequential printing processes of ink or photoresist materials. The printing processes include a gravure offset method and a transfer method depending upon how the photoresist material is applied to the upper mid lower substrates. The gravure offset method includes steps of filling the photoresist material into a groove of a cliché, transferring the photoresist material filled in the groove onto a roller; and applying the transferred photoresist material onto the upper or lower substrate.
FIGS. 2A
to
2
D are cross-sectional views of a sequential printing process according to a gravure offset printing method according to the conventional art. In
FIG. 2A
, a photoresist or ink material
29
is filled into a plurality of rectangular grooves
26
formed in a surface of a cliché, wherein the plurality of rectangular grooves are spaced apart to define a pattern Next, any excess photoresist material
29
that remains on the surface of the cliché is removed by a doctor blade
27
. Accordingly, the photoresist material
29
only remains in each of the plurality of rectangular grooves
26
In
FIG. 2B
, a roller
25
is rolled across the surface of the cliché along a first direction so that individual photoresist material portions
24
of the photoresist material
29
(in
FIG. 2A
) that filled each of the plurality of rectangular grooves
26
(in
FIG. 2A
) are temporarily bonded onto a blanket
28
or the roller
25
Accordingly, the pattern of the photoresist-filled rectangular grooves
26
(in
FIG. 2A
) is transferred onto the blanket
28
as the individual photoresist material portions
24
.
In
FIG. 2C
, the roller
25
is placed above a substrate
10
and the individual photoresist material portions
24
are transferred onto a surface of the substrate
10
corresponding to the pattern of the photoresist-filled rectangular grooves
26
(in FIG.
2
A). The substrate
10
may be formed of a glass or plastic substrate material.
In
FIG. 2D
, the individual photoresist material portions
24
are completely transferred to the surface of the substrate
10
, and the printing process is completed Thus, the pattern of the grooves
26
(in
FIG. 2A
) is replicated onto the surface of the substrate
10
.
FIGS. 3A
to
3
D are cross-sectional views of a sequential printing process according to a transfer method according to the conventional art. In
FIG. 3A
, a photoresist or ink material
29
is filled into a plurality of rectangular grooves
26
formed in a surface of a cliché, wherein the plurality of rectangular grooves are spaced apart to define a pattern. Next, any excess photoresist material
29
that remains on the surface of the cliché is removed by a doctor blade
27
. Accordingly, the photoresist material
29
only remains in each of the plurality of rectangular grooves
26
In
FIG. 3B
, a surface of a substrate
10
, which may be formed of a glass or plastic material, is placed upon the surface of the cliché to contact uppermost surfaces of individual photoresist material portions
24
filled in each of plurality of rectangular grooves
26
(in FIG.
3
A). Then, heat and/or pressure is applied to the substrate
10
and cliché to bond each of the individual photoresist material portions
24
onto the surface of the sub
Lee Dong-Hoon
Yi Jong-Hoon
LG. Philips LCD Co. Ltd.
Morgan & Lewis & Bockius, LLP
Picardat Kevin M.
LandOfFree
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