Radiation imagery chemistry: process – composition – or product th – Imaging affecting physical property of radiation sensitive... – Making named article
Reexamination Certificate
2002-11-05
2004-07-13
McPherson, John A. (Department: 1756)
Radiation imagery chemistry: process, composition, or product th
Imaging affecting physical property of radiation sensitive...
Making named article
C430S394000, C347S047000
Reexamination Certificate
active
06762012
ABSTRACT:
CROSS-REFERENCE TO RELATED APPLICATIONS
This application claims the benefit of Korean Patent Application No. 2001-68631, filed Nov. 5, 2001, in the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a method of manufacturing an ink-jet printhead, and more particularly, to a method of manufacturing a monolithic ink-jet printhead using a negative photoresist.
2. Description of the Related Art
In general, ink-jet printheads are devices for printing a predetermined color image by ejecting a small volume of a droplet of ink at a desired position on a recording sheet. In these ink-jet printheads, the ink is supplied to an ink chamber from an ink reservoir via an ink feed hole and a restrictor. The ink filled in the ink chamber is heated by a heating element provided in the ink chamber and is ejected in a droplet shape through nozzles by a pressure of bubbles generated by the heating element.
In general, the ink-jet printheads require a structure in which a number of nozzles are highly integrated, as the ink-jet printheads realize high resolution and high speed printing. In this case, a shape and precision of each nozzle and uniformity and precision between cells of the ink passage are the most important process variables for improving printing performances and realizing high quality images.
FIGS. 1A through 1H
are cross-sectional views illustrating a conventional method of manufacturing an ink-jet printhead using a roof shooting method. Basically, a photolithography process and an electro forming process are used in the method of manufacturing the ink-jet printhead using the roof shooting method.
The method of manufacturing the ink-jet printhead using the roof shooting method includes manufacturing a nozzle plate
15
as shown in
FIGS. 1A through 1D
, forming an ink passage including an ink feed hole
22
, a restrictor
27
, and an ink chamber
26
on a head chip substrate
21
on which a heating element
23
is formed as shown in
FIGS. 1E through 1G
, and attaching the nozzle plate
15
to the head chip substrate
21
to complete the ink-jet printhead as shown in FIG.
1
H.
More specifically, a seeding layer
12
for the electro forming process is formed on a silicon substrate
11
as shown in
FIG. 1A
, and positive photoresist
13
is coated on the seeding layer
12
. That is, the seeding layer
12
is formed to a thickness of several thousand Å by sputtering or depositing NiV on the silicon substrate
11
. The positive photoresist
13
is coated to a thickness of about several &mgr;m, i.e., usually to a thickness between 4 &mgr;m and 8 &mgr;m, through spin coating. Subsequently, the positive photoresist
13
is selectively exposed to a beam hv using a photomask
14
.
Subsequently, the exposed photoresist
13
is developed. In this case, only a remaining photoresist
13
a
of an unexposed portion of the positive photoresist
13
remains on the seeding layer
12
as shown in
FIG. 1B. A
crater
15
b
will be formed by the remaining photoresist
13
a
around a nozzle
15
a
shown in FIG.
1
D.
FIG. 1C
illustrates a case where the nozzle plate
15
of nickel is formed on the seeding layer
12
by soaking the patterned substrate
11
in a plating container and performing the electro forming process. In this case, the nozzle plate
15
can be formed to a desired thickness by adjusting a total current density and a plating time applied to the plating container. Simultaneously, plating is suppressed on the remaining photoresist
13
a
, and thus the nozzle
15
a
is formed.
After the electro forming process is completed, the nozzle plate
15
is separated from the substrate
11
and is cleaned as shown in FIG.
1
D. In this case, the crater
15
b
is formed by the remaining photoresist
13
a
around the nozzle
15
a.
FIG. 1E
illustrates a case where a negative photoresist
24
is coated on the head chip substrate
21
on which the heating element
23
formed of a resistance heating body and the ink feed hole
22
are formed. The negative photoresist
24
is coated on the head chip substrate
21
by a lamination method of heating and pressurizing and compressing a dry film resist of resin, such as VACREL or RISTON manufactured by DUPONT, on the head chip substrate
21
.
Subsequently, the negative photoresist
24
is selectively exposed to the beam hv using a second photomask
25
as shown in FIG.
1
F. As a result, an exposed portion of the negative photoresist
24
is cured, and a barrier wall
24
a
surrounding the ink chamber
26
is formed as shown in FIG.
1
G. An unexposed portion of the negative photoresist
24
is removed using solvent, and thus the ink chamber
26
and a restrictor
27
are formed. The restrictor
27
is a connection path formed between the ink feed hole
22
and the ink chamber
26
.
Last, the previously-manufactured nozzle plate
15
is heated and pressurized on the barrier wall
24
a
and is attached to the head chip substrate
21
, thereby the ink-jet printhead is manufactured as shown in FIG.
1
H.
The above-mentioned method of manufacturing a nozzle plate is well known as a Mandrel type nozzle electro forming method. At present, many manufactures employ the method in manufacturing a color ink-jet printhead and a mono ink-jet printhead having a small number of nozzles.
However, the method shown in
FIGS. 1A through 1H
causes many problems as the integration of a cell marked by cell per inch (CPI) and the number of the nozzles
15
a
increase. First, since the nozzle plate
15
should be separately manufactured and attached to the head chip substrate
21
, high precision is necessary in this process. Second, misalignment between the nozzle
15
a
and the heating element
23
may occur because thermal expansion coefficients of the nozzle plate
15
and the head chip substrate
21
are different from each other when the nozzle plate
15
is heated and attached to the head chip substrate
21
. Third, since one electro forming process, two photolithography processes, and one adhesion process should be performed, a process of manufacturing the ink-jet printhead becomes very complicated.
Accordingly, another method of manufacturing the ink-jet printhead by monolithically forming elements, such as the ink passage and the nozzle, on the head chip substrate has been recently introduced.
FIG. 2
is a perspective view of a conventional ink-jet printhead using a side shooting method, and
FIGS. 3A through 3E
are cross-sectional views illustrating a method of monolithically manufacturing the ink-jet printhead shown in FIG.
2
. Drawings on the left side of
FIGS. 3A through 3E
are cross-sectional views taken along line A—A of
FIG. 2
, and drawings on the right side of
FIGS. 3A through 3E
are cross-sectional views taken along line B—B of
FIG. 2. A
photolithography process is basically used in the method, but the electro forming process and the adhesion process are not used in this method.
Referring to
FIG. 2
, the conventional ink-jet printhead using the side shooting method has a structure in which an ink passage forming wall
41
forming an ink feed hole
45
, an ink chamber
42
, and an ink passage
43
are stacked on a head chip substrate
31
. A heating element
32
is formed at one side of the ink passage
43
, i.e. in a portion adjacent to the ink chamber
42
, and a nozzle
44
is formed at the other side of the ink passage
43
.
The method of monolithically manufacturing the ink-jet printhead having the above structure will be described stepwise below.
A positive photoresist
33
is coated to a thickness of about several ten &mgr;m on the head chip substrate
31
on which the heating element
32
of a resistance heating body is formed as shown in FIG.
3
A. Subsequently, the positive photoresist
33
is selectively exposed to a beam hv using a photomask
34
.
Next, the exposed photoresist
33
is developed. In this case, only a remaining photoresist
33
a
of an unexposed portion of the positive photoresist
3
Cho Seo-hyun
Jung Myung-song
Kim Kyong-il
Kim Tae-kyun
Park Sung-joon
McPherson John A.
Samsung Electronics Co,. Ltd.
Staas & Halsey LLP.
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