Semiconductor device manufacturing: process – Manufacture of electrical device controlled printhead
Reexamination Certificate
2002-09-19
2004-10-19
Ghyka, Alexander (Department: 2812)
Semiconductor device manufacturing: process
Manufacture of electrical device controlled printhead
C438S510000, C438S689000, C347S068000, C347S071000
Reexamination Certificate
active
06806108
ABSTRACT:
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 having an ink passage that is monolithically formed on a silicon substrate.
2. Description of the Related Art
In general, an ink-jet printhead is a device printing a predetermined color image by ejecting small droplets of printing ink onto a desired place of a recording sheet.
The ink-jet printhead may eject ink using an electro-thermal transducer (bubble jet-type ink ejection mechanism) which generates a bubble in ink using a heater, or using an electromechanical transducer, which causes a volume variation of ink by a deformation of a piezoelectric device.
The bubble jet-type ink ejection mechanism will be described in greater detail. When power is supplied to the heater having a resistance heating element, ink disposed adjacent to the heater is rapidly heated to a temperature of about 300° C. In such a case, the bubble is generated in the ink and expanded to apply pressure to the ink filling an ink chamber. As a result, the ink near a nozzle is ejected from the ink chamber through the nozzle.
FIGS. 1A and 1B
are examples of a conventional bubble jet type ink-jet printhead, and give an exploded perspective view showing a structure of the conventional bubble jet type inkjet printhead disclosed in U.S. Pat. No. 4,882,595 and a cross-sectional view illustrating a method of ejecting an ink droplet in the conventional bubble jet type ink-jet printhead, respectively.
Referring to
FIGS. 1A and 1B
, the conventional bubble jet-type ink-jet printhead includes a substrate
10
, a barrier wall
38
installed on the substrate
10
to form an ink chamber
26
filled with ink
49
, a heater
12
installed in the ink chamber
26
, and a nozzle plate
18
in which a nozzle
16
is formed through which an ink droplet
49
′ is ejected. The ink chamber
26
is filled with the ink
49
through an ink channel
24
from an ink supply manifold
14
connected to an ink reservoir (not shown), and the nozzle
16
connected to the ink chamber
26
is filled with the ink
49
by capillary action. A plurality of nozzles
16
, a plurality of heaters
12
corresponding to the plurality of nozzles
16
, and the ink chambers
26
are arranged in columns adjacent to the ink supply manifold
14
or in columns at both sides of the ink supply manifold
14
.
In the above structure, when current is supplied to the heater
12
, the heater
12
generates heat to form a bubble
48
in the ink
49
filling the ink chamber
26
. After that, the bubble
48
is expanded to apply pressure to the ink
49
and push the ink droplet
49
′ out of the ink chamber
26
through the nozzle
16
. New ink
49
is sucked through the ink channel
24
to refill the ink chamber
26
.
However, in order to manufacture the conventional printhead having the above structure, the nozzle plate
18
and the substrate
10
should be separately manufactured and bonded to each other, resulting in a complicated printhead manufacturing process, and causing a misalignment of the nozzle plate
18
and the substrate
10
when the nozzle plate
18
is bonded to the substrate
10
.
Thus, recently, in order to solve the above problems, an ink-jet printhead that is monolithically formed on a silicon substrate has been suggested. The printhead is usually manufactured by using semiconductor device manufacturing techniques such as deposition of material layers, photolithography, and etching. These techniques prevent the misalignment between elements of the printhead, and since they are based on conventional semiconductor device manufacturing processes, the printhead manufacturing process might be simplified, and mass production is facilitated.
As an example of a printhead that is monolithically formed on a silicon substrate, another structure of the conventional ink-jet printhead disclosed in European Publication Patent No. EP 1 078 754 A2 is shown in FIG.
2
.
Referring to
FIG. 2
, a plurality of thin material layers
52
,
54
,
56
, and
58
are stacked on a silicon substrate
50
. A resistor layer
70
for heating ink is formed between the material layers
52
,
54
,
56
, and
58
. The material layers
52
,
54
,
56
, and
58
and the resistor layer
70
are formed by oxidation of a surface of the silicon substrate
50
, deposition of a predetermined material on the silicon substrate
50
, and etching using an etch mask formed by photolithography. An ink feed hole
74
is formed to perforate the material layers
52
,
54
,
56
, and
58
. The ink feed hole
74
is formed by dry or wet etching the material layers
52
,
54
,
56
, and
58
after forming the etch mask on the material layers
52
,
54
,
56
, and
58
by a photolithographic process. An ink supply manifold
72
is formed by dry or wet etching a rear side of the silicon substrate
50
. An orifice layer
60
defining a nozzle
78
and an ink chamber
76
is formed on the material layers
532
,
54
,
56
, and
58
. The orifice layer
60
is formed by coating a photoresist on the material layers
52
,
54
,
56
, and
58
through lamination, screen printing, or spin coating, and the nozzle
78
and the ink chamber
76
are formed by the photolithographic process.
As described above, in the ink-jet printhead having the structure shown in
FIG. 2
, elements constituting an ink passage on the silicon substrate
50
, that is, the ink supply manifold
72
, the ink feed hole
74
, the ink chamber
76
, and the nozzle
78
are formed through photolithography and/or etching, and thus the ink-jet printhead having the structure shown in
FIG. 2
might have the advantages described above.
However, according to the conventional method of forming the ink passage described above, the ink passage is formed by a dry etching technique, such as reactive ion etching or inductively coupled plasma etching, or by a wet etching technique using KOH and TMAH. Dry etching is mostly anisotropic etching, and since it is difficult to process the ink passage having a complicated internal structure, there are limitations in a processing depth of the ink passage, and a processed surface of the ink passage is also rough. In addition, undesired portions are etched, and since the etch mask must be formed by the photolithographic process, a processing time and a manufacturing cost of the ink-jet printhead increase. In the case of wet etching, the processed surface is comparatively flat, but the etching process easily etches other materials as well as silicon, and thus, it is difficult to selectively etch only a desired portion, and the etching time is extended compared to the dry etching.
As described above, according to the conventional method of manufacturing a monolithic ink-jet printhead using dry etching and wet etching in consideration of a shape and size of the ink passage, the wall of the ink passage is comparatively rough, and it is difficult to precisely adjust the size of the ink passage to a design dimension.
SUMMARY OF THE INVENTION
To solve the above and other problems, it is an object of the present invention to provide a method of manufacturing a monolithic ink-jet printhead, the method particularly including reprocessing an internal side of the ink passage using XeF
2
gas after forming the ink passage on a silicon substrate.
Additional objects and advantageous of the invention will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the invention.
Accordingly, to achieve the above and other objects, there is provided a method including forming an ink passage on a silicon substrate, the ink passage having a manifold supplying ink, an ink chamber receiving the ink from the manifold, an ink channel connecting the manifold to the ink chamber, and a nozzle through which the ink is ejected from the ink chamber.
In the method of manufacturing the printhead according an embodiment of the present inventio
Cho Seo-hyun
Kuk Keon
Lee Sang-wook
Min Jae-sik
Park Yong-shik
LandOfFree
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