BRIEF DESCRIPTION OF THE DRAWINGS
These and/or other aspects and utilities of the present general inventive concept will become apparent and more readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings of which:
FIG. 1 is a schematic sectional view illustrating a conventional inkjet printhead;
FIG. 2 is a schematic plan view illustrating an inkjet printhead according to an embodiment of the present general inventive concept;
FIG. 3 is a sectional view illustrating the inkjet of FIG. 2 taken along line III-III′;
FIG. 4 is a view illustrating a nozzle layer that can be used for an inkjet printhead according to an embodiment of the present general inventive concept;
FIGS. 5 through 12 are views illustrating a method of manufacturing an inkjet printhead according to an embodiment of the present general inventive concept;
FIGS. 13 through 16 are views illustrating a method of manufacturing an inkjet printhead according to another embodiment of the present general inventive concept;
FIGS. 17 through 22 are views illustrating a method of manufacturing an inkjet printhead according to another embodiment of the present general inventive concept; and
FIGS. 23 through 26 are views illustrating a method of manufacturing an inkjet printhead according to yet another embodiment of the present general inventive concept.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Reference will now be made in detail to the embodiments of the present general inventive concept, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to the like elements throughout. The embodiments are described below in order to explain the present general inventive concept by referring to the figures. The embodiments described are just exemplary, and it will be understood that various changes may be made therein. For example, it will also be understood that when a layer is referred to as being “on” another layer or substrate, it can be directly on the other layer or substrate, or intervening layers may also be present. Each element of the inkjet printhead can be formed of a different material from the materials described in the exemplary embodiments. Furthermore, each element of the inkjet printhead can be formed using a stacking or forming method different from the illustrated one. In the method of forming the inkjet printhead according to the present general inventive concept, operations of the method can be performed in a different order from the illustrated order.
FIG. 2 is a schematic plan view illustrating an inkjet printhead according to an embodiment of the present general inventive concept, and FIG. 3 is a sectional view illustrating the inkjet taken along line III-III′ of FIG. 2.
Referring to FIGS. 2 and 3, the inkjet printhead according to this embodiment may include a substrate 110 on which a plurality of material layers are formed, a chamber layer 120 formed above the substrate 110, and a nozzle layer 130 formed on the chamber layer 120.
The substrate 110 may be formed of a silicon substrate. An ink feed hole 111 is formed in the substrate 110 to supply ink. The ink feed hole 111 can be formed through the substrate 110 in a perpendicular direction with respect to a surface of the substrate 110. An insulating layer 112 can be formed on the substrate 110 to thermally and electrically insulate the substrate 110 and the heaters 114 from each other. The insulating layer 112 may be formed of a silicon oxide. The heaters 114 can be formed on the insulating layer 112 to create ink bubbles by heating ink filled in ink chambers 122. The heaters 114 may be formed of a resistive heating material, such as a tantalum-aluminum alloy, a tantalum nitride, a titanium nitride, or a tungsten silicide. A plurality of electrodes 116 can be formed on each of the heaters 114 to apply a current to each of the heaters 114. The electrodes 116 are formed of a material having high electric conductivity, for example, aluminum (Al), an aluminum alloy, gold (Au), or silver (Ag).
Further, a passivation layer 118 may be formed on the heaters 114 and the electrodes 116. The passivation layer 118 prevents the heaters 114 and the electrodes 116 from oxidizing or corroding due to contact with ink. The passivation layer 118 may be formed of a silicon oxide or a silicon nitride. A plurality of anti-cavitation layers 119 may be further formed on a bottom surface of the ink chambers 122. That is, the anti-cavitation layers 119 may be formed on the passivation layer 118 above the heaters 114 and the electrodes 116. The anti-cavitation layers 119 protect the heaters 114 from cavitation forces generated when ink bubbles collapse. The anti-cavitation layers 119 may be formed of tantalum (Ta).
The chamber layer 120 can be formed on the passivation layer 118. The plurality of ink chambers 122 filled with ink supplied from the ink feed hole 111 are formed in the chamber layer 120. The ink chambers 122 are located above the heaters 114, respectively. Further, a plurality of restrictors 124 may be formed in the chamber layer 120 to connect the ink feed hole 111 with the ink chambers 122.
The nozzle layer 130 is formed on the chamber layer 120. The ink filled in the ink chambers 122 is ejected to the outside through a plurality of nozzles 132 of the nozzle layer 130. The nozzles 132 are located above the respective ink chambers 122. A diameter of each nozzle 132 may be approximately 12 μm, but the present general inventive concept is not limited thereto. A plurality of via holes 135 are formed through the nozzle layer 130. The via holes may be located above the ink feed hole 111. A diameter of each via hole 135 may be approximately from 2 to 15 μm, but is not limited thereto. The via holes 135 considerably reduce a development process time to form the nozzles 132 and the ink chambers 122 in manufacturing the inkjet printhead, as described later. Therefore, the inkjet printhead can be manufactured in less time due to the via holes 135 formed through the nozzle layer 130. In the current embodiment, each section of the via holes 135 is circular, but the present general inventive concept is not limited thereto, and the via holes 135 may have various shapes. For example, referring to FIG. 4, via holes 135′ of a slit-shape can be formed through a nozzle layer 130′ including nozzles 132′.
FIGS. 5 through 12 are views illustrating a method of manufacturing an inkjet printhead according to an embodiment of the present general inventive concept.
Referring to FIG. 5, a substrate 210 can be prepared. Generally, a silicon substrate may be used for the substrate 210. An insulating layer 212 is formed to a predetermined thickness on the substrate 210. The insulating layer 212 thermally and electrically insulates the substrate 210 and heaters, to be described later, from each other. The insulating layer 212 may be formed of a silicon oxide. Next, a plurality of heaters 214 are formed on the insulating layer 212 to generate ink bubbles by heating ink. A resistive heating material, such as a tantalum-aluminum alloy, a tantalum nitride, a titanium nitride, or a tungsten silicide, may be deposited on the insulating layer 212, and the deposited resistive heating material may be patterned to form the heaters 214. Electrodes 216 to apply a current to the heaters 214 are formed on each of the heaters 214. A metal having high electric conductivity, such as aluminum (Al), aluminum alloy, gold (Au), and silver (Ag), may be deposited on the heaters 214, and the deposited material may be patterned to form the electrodes 216.
Referring to FIG. 6, a passivation layer 218 can be formed on the insulating layer 212 to cover the heaters 214 and the electrodes 216. The passivation layer 218 prevents the heaters 214 and the electrodes 216 from contacting the ink, thereby protecting the heaters 214 and the electrodes 216 against oxidization or corrosion. The passivation layer 218 may be formed of a silicon oxide or a silicon nitride. Anti-cavitation layers 219 are formed on bottom surfaces of ink chambers 222 (refer to FIG. 12) to be described later. That is, the anti-cavitation layers 219 can be formed on the passivation layer 218 above the respective heaters 214. The anti-cavitation layers 219 protect the heaters 214 from cavitation forces generated when ink bubbles collapse. For example, tantalum (Ta) may be deposited on the passivation layer 128 and then the deposited tantalum (Ta) may be patterned to form the anti-cavitation layers 219.
Referring to FIG. 7, a chamber material layer 220′ is formed to a predetermined thickness on a whole surface of the resulting structure illustrated in FIG. 6. The chamber material layer 220′ may be formed of a negative photoresist of which a non-exposed region can be removed with a developer.
Referring to FIG. 8, a first photomask 251 including an ink chamber pattern is disposed above the chamber material layer 220′, and then the chamber material layer 220′ is exposed using the first photomask 251. Then, a chamber layer 220 defining a plurality of ink chambers 222 (refer to FIG. 12) is formed in the chamber material layer 220′. Further, a plurality of restrictors 224 (refer to FIG. 12) may be defined by the chamber layer 220 to connect an ink feed hole 211 (refer to FIG. 12) with the ink chambers 222. Specifically, an exposed portion of the chamber material layer 220′ will be the chamber layer 220, and a non-exposed chamber material region 220′a of the chamber material layer 220′ will be removed with a developer in a development process, to be described later, to form the plurality of ink chambers 222.
Referring to FIG. 9, after the exposure process of FIG. 8, a nozzle material layer 230′ is formed on the chamber layer 220 and the non-exposed chamber material region 220′a to a predetermined thickness. The nozzle material layer 230′ may be formed of a negative photoresist of which a non-exposed region is removed with a developer, as can also be the case of the aforementioned chamber material layer 220′ as described above.
Referring to FIG. 10, a second photomask 252 including a nozzle pattern is disposed above the nozzle material layer 230′ and the nozzle material layer 230′ is exposed using the second photomask 252 for a predetermined time. Then, a nozzle layer 230 defining a plurality of nozzles 232 (refer to FIG. 12) is formed in the nozzle material layer 230′. Specifically, an exposed portion of the nozzle material layer 230′ will be the nozzle layer 230, and a non-exposed region 230′a of the nozzle material layer 230′ will be removed with a developer in a development process to be described later to form the plurality of nozzles 232. In the exposure process for the nozzle material layer 230′, when an exposure time is controlled such that only the nozzle material layer 230′ is exposed, it becomes easy to obtain the nozzle layer 230 and the chamber layer 220 of a desired thickness. Meanwhile, when the nozzle material layer 230′ is formed of a material having a little different light transmittance from the light transmittance of the chamber material layer 220′, it can be easier to obtain the nozzle layer 230 and the chamber layer 220 of a desired thickness.
Referring to FIG. 11, the substrate 210 is etched from its rear surface to form an ink feed hole 211 to supply ink. The ink feed hole 211 may be formed through the substrate 210 and the insulating layer 212 using etching such that a bottom surface of the non-exposed chamber material region 220′a is exposed. The ink feed hole 211 may be formed to a predetermined width, perpendicularly to a surface of the substrate 210. The ink feed hole 211 may be formed of various shapes, such as a shape tapered in an upward direction.
Referring to FIG. 12, the non-exposed nozzle material region 230′a in the nozzles 232 and the non-exposed chamber material region 220′a in the ink chambers 222 are removed with a developer. Accordingly, the plurality of ink chambers 222 are formed in the chamber layer 220, and the plurality of nozzles 232 are formed in the nozzle layer 230. Here, the ink chambers 222 are located above the respective heaters 214, and the nozzles 232 are located above the respective ink chambers 222. The plurality of restrictors 224 may be further formed in the chamber layer 220 to connect the ink feed hole 211 with the ink chambers 222.
In the above embodiment, the chamber material layer 220′ and the nozzle material layer 230′ are formed of a negative photoresist, but the general inventive concept is not limited thereto, and the chamber material layer 220′ and the nozzle material layer 230′ may be formed of a positive photoresist of which an exposed portion is removed with a developer. In this case, a non-exposed region of the chamber material layer 220′ will be the chamber layer 220, and an exposed portion of the chamber material layer 220′ will be removed with a developer to form the plurality of ink chambers 222. Also, a non-exposed region of the nozzle material layer 230′ will be the nozzle layer 230, and an exposed portion of the nozzle material layer 230′ will be removed with a developer to form the plurality of nozzles 232.
As described above, in the above embodiment, since the chamber layer 220 and the nozzle layer 230 can be formed using two exposure processes and one development process, the inkjet printhead can be manufactured using a simplified process.
Hereinafter, a method of manufacturing an inkjet printhead will now be described according to another embodiment of the present general inventive concept. FIGS. 13 through 16 are views illustrating a method of manufacturing an inkjet printhead according to another embodiment of the present general inventive concept. Hereinafter, aspects different from the embodiment of FIGS. 5 through 12 will be mainly described. The processes illustrated with reference to FIGS. 5 through 9 are similar to the above embodiment, and thus drawings and specific descriptions thereof will be omitted. FIG. 13 is the same view as FIG. 9.
Referring to FIG. 14, a second photomask 253 including a nozzle pattern and a via hole pattern is disposed above the nozzle material layer 230′, and then the nozzle material layer 230′ is exposed using the second photomask 253 for a predetermined time. Then, a nozzle layer 230 defining a plurality of nozzles 232 (refer to FIG. 16) and a plurality of via holes 235 (refer to FIG. 16) is formed in the nozzle material layer 230′. Specifically, an exposed portion of the nozzle material layer 230′ will be the nozzle layer 230, and a non-exposed region, that is, a nozzle material layer 230′a in the nozzles 232 and a nozzle material layer 230′b in the via holes 235 will be removed with a developer in a development process to form the plurality of nozzles 232 and the plurality of via holes 235.
Referring to FIG. 15, the substrate 210 is etched from its rear surface to form an ink feed hole 211 to supply ink. The ink feed hole 211 may be formed through the substrate 210 and the insulating layer 212 using etching, such that a bottom surface of the non-exposed chamber material region 220′a is exposed.
Referring to FIG. 16, the non-exposed nozzle material regions 230′a and 230′b in the nozzles 232 and the via holes 235 and the non-exposed chamber material region 220′a in the ink chambers 222 are removed with a developer. Here, since the developer flowing in through the via holes 235 as well as the nozzles 232 and the ink feed holes 211 removes the non-exposed chamber material region 220′a, a development process time is reduced, compared to the embodiment of FIGS. 5 through 12, thus reducing a manufacturing time of the inkjet printhead. The plurality of ink chambers 222 are formed in the chamber layer 220 and the plurality of nozzles 232 and the plurality of via holes 235 are formed in the nozzle layer 230 through the development process. Meanwhile, the plurality of restrictors 224 may be further formed in the chamber layer 220 to connect the ink feed hole 211 with the ink chambers 222.
In the current embodiment, the chamber material layer 220′ and the nozzle material layer 230′ are formed of a negative photoresist, but may be formed of a positive photoresist of which an exposed portion is removed with a developer.
FIGS. 17 through 22 are views illustrating a method of manufacturing an inkjet printhead according to another embodiment of the present general inventive concept. Hereinafter, aspects different from the above-described embodiments will be mainly described. The processes illustrated with reference to FIGS. 5 and 6 are the same in the current embodiment, and thus drawings and specific descriptions thereof will be omitted.
Referring to FIG. 17, a chamber material layer 320′ is formed to a predetermined thickness on a whole surface of the resulting structure illustrated in FIG. 6. The chamber material layer 320′ may be formed of a negative photoresist of which a non-exposed region is removed with a developer. In FIG. 17, reference numerals 310, 312, 314, 316, 318, and 319 represent a substrate, an insulating layer, heaters, electrodes, a passivation layer, and anti-cavitation layers, respectively.
Referring to FIG. 18, a nozzle material layer 330′ is formed to a predetermined thickness on the chamber material layer 320′. The nozzle material layer 330′ may be formed of a negative photoresist. Meanwhile, when the nozzle material layer 330′ is formed of a material having a little different light transmittance with the transmittance of the chamber material layer 320′, it becomes easy to obtain a nozzle layer 330 (refer to FIG. 22) and a chamber layer 320 (refer to FIG. 22) of a desired thickness. Further, a light transmission restricting layer (not illustrated) may be formed on the chamber material layer 320′ before forming the nozzle material layer 330′. Since the light transmission restricting layer interposed between the nozzle material layer 330′ and the chamber material layer 320′ restricts the transmission of an ultraviolet ray, it becomes easier to obtain the nozzle layer 330 and the chamber layer 320 of a desired thickness.
Referring to FIG. 19, a first photomask 351 including an ink chamber pattern is disposed above the nozzle material layer 330′, and then the nozzle material layer 330′ and the chamber material layer 220′ are exposed using the first photomask 351. Then, a chamber layer 320 defining a plurality of ink chambers 322 (refer to FIG. 22) is formed in the chamber material layer 320′ under the nozzle material layer 330′. Specifically, an exposed portion of the chamber material layer 320′ will be the chamber layer 320, and a non-exposed region 320′a of the chamber material layer 320′ will be removed with a developer in a development process to be described later to form the plurality of ink chambers 322. Further, a plurality of restrictors 324 (refer to FIG. 22) may be formed in the chamber layer 320 to connect an ink feed hole 311 (refer to FIG. 22) with the ink chambers 322. An exposed portion 331 of the nozzle material layer 330′ will have the same shape as the chamber layer 320.
Referring to FIG. 20, a second photomask 352 including a nozzle pattern is disposed above the nozzle material layer 330′ where the exposure process is performed, and the nozzle material layer 330′ is exposed using the second photomask 352. Then, a nozzle layer 330 defining a plurality of nozzles 332 (refer to FIG. 22) is formed in the nozzle material layer 330′. Specifically, an exposed portion of the nozzle material layer 330′ will be the nozzle layer 330, and a non-exposed region 330′a of the nozzle material layer 330′ will be removed with a developer in a development process to be described later to form the plurality of nozzles 332. In the exposure process for the nozzle material layer 330′, when an exposure time is controlled such that only the nozzle material layer 330 is exposed, it becomes easy to obtain the nozzle layer 330 and the chamber layer 320 of a desired thickness. Meanwhile, when the nozzle material layer 330′ is formed of a material having a little different light transmittance from the light transmittance of the chamber material layer 320′, it becomes easy to obtain the nozzle layer 330 and the chamber layer 320 of a desired thickness. Further, when a light transmission restricting layer (not illustrated) may be formed on the chamber material layer 320′ before forming the nozzle material layer 330′, it becomes easier to obtain the nozzle layer 330 and the chamber layer 320 of a desired thickness.
Referring to FIG. 21, the substrate 310 is etched from its rear surface to form an ink feed hole 311 to supply ink. The ink feed hole 311 may be formed through the substrate 310 and the insulating layer 312 using etching such that a bottom surface of the non-exposed chamber material region 320′a is exposed.
Referring to FIG. 22, the non-exposed nozzle material regions 330′a in the nozzles 332 and the non-exposed chamber material region 320′a in the ink chambers 322 are removed with a developer. Then, the plurality of ink chambers 322 are formed in the chamber layer 320, and the plurality of nozzles 332 are formed in the nozzle layer 330. Meanwhile, a plurality of restrictors 324 may be further formed to connect the ink feed hole 311 with the ink chambers 322.
In the above embodiment, the chamber material layer 320′ and the nozzle material layer 330′ are formed of a negative photoresist, but may also be formed of a positive photoresist of which an exposed portion is removed with a developer.
As described above, in the above embodiment, since the chamber layer 320 and the nozzle layer 330 can be formed using two exposure processes and one development process, the inkjet printhead can be manufactured using a simplified process.
FIGS. 23 through 26 are views illustrating a method of manufacturing an inkjet printhead according to another embodiment of the present general inventive concept. Hereinafter, aspects different from the above-described embodiments will be mainly described. The processes illustrated with reference to FIGS. 17 through 19 are similar in this embodiment, and thus drawings and specific descriptions thereof will be omitted. FIG. 23 is the same as FIG. 19.
Referring to FIG. 24, a second photomask 353 including a nozzle pattern and a via hole pattern is disposed above the nozzle material layer 330′ where the exposure process is performed, and the nozzle material layer 330′a is exposed using the second photomask 353. Then, a nozzle layer 330 defining a plurality of nozzles 332 (refer to FIG. 26) and a plurality of via holes 335 (refer to FIG. 26) is formed in the nozzle material layer 330′. Specifically, an exposed portion of the nozzle material layer 330′ will be the nozzle layer 330, and a non-exposed region of the nozzle material layer 330′, that is, a nozzle material layer 330′a in the nozzles 332 and a nozzle material layer 330′b in the via holes 335 will be removed with a developer in a development process to form the plurality of nozzles 332 and the plurality of via holes 335.
Referring to FIG. 25, the substrate 310 is etched from its rear surface to form an ink feed hole 311 for supplying ink. The ink feed hole 311 may be formed through the substrate 310 and an insulating layer 324 using etching such that a bottom surface of the non-exposed chamber material region 320′a is exposed.
Referring to FIG. 26, the non-exposed nozzle material regions 330′a and 330′b in the nozzles 332 and the via holes 335 and the non-exposed chamber material region 320′a in the ink chambers 322 are removed with a developer. Here, since a developer flowing in through the via holes 335 as well as the nozzles 332 and the ink feed holes 311 removes the non-exposed chamber material region 320′a, a development process time can be reduced, thus reducing the manufacturing time of the inkjet printhead. The plurality of ink chambers 322 are formed in the chamber layer 320 and the plurality of nozzles 332 and the plurality of via holes 335 are formed in the nozzle layer 330 through the development process. Meanwhile, a plurality of restrictors 324 may be further formed in the chamber layer 320 to connect the ink feed hole 311 with the ink chambers 322.
In this embodiment, the chamber material layer 320′ and the nozzle material layer 330′ are formed of a negative photoresist, but may also be formed of a positive photoresist of which an exposed portion is removed with a developer.
As described above, according to the present general inventive concept, a chamber layer and a nozzle layer are formed through two exposure processes and one development process. Therefore, an inkjet printhead can be manufactured using a simplified process, compared to a conventional method that requires forming of a sacrificial layer and a CMP process, thus reducing a manufacturing time. Also, when a plurality of via holes are formed in the nozzle layer, the manufacturing time of the inkjet printhead can be reduced even more.
Although a few embodiments of the present general inventive concept have been shown and described, it will be appreciated by those skilled in the art that changes may be made in these embodiments without departing from the principles and spirit of the general inventive concept, the scope of which is defined in the appended claims and their equivalents.
Patent Application
20080079781
