This application claims the benefit of Korean Patent Application No. 2004-66546, filed Aug. 23, 2004, the disclosure of which is hereby incorporated herein by reference in its entirety.
1. Field of the Invention
The present general inventive concept relates to an ink jet head and a method of fabricating the same, and more particularly, to an ink jet head including a metal chamber layer and a method of fabricating the same.
2. Description of the Related Art
An ink jet recording device functions to print an image by ejecting fine droplets of printing ink to a desired position on a recording medium. Ink jet recording devices have been widely used due to their inexpensive price and characteristics capable of printing numerous colors at a high resolution. The ink jet recording device includes an ink jet head for actually ejecting ink and an ink container in fluid communication with the ink jet head. The ink stored in the ink container is supplied into the ink jet head through an ink-feed passage, and the ink jet head ejects the ink supplied from the ink container to the recording medium to perform a printing operation.
A process of fabricating the ink jet head may be classified as a hybrid type or a monolithic type depending upon a method of forming a chamber layer and a nozzle layer of the ink jet head. According to the hybrid type the chamber layer and the nozzle layer having nozzles for ejecting ink are separately formed on a substrate having pressure generating elements thereon. The nozzle layer may be adhered to the chamber layer to fabricate the ink jet head. However, misalignment may occur between the pressure-generating elements and the nozzles during the process of adhering the nozzle layer to the chamber layer. In addition, the process may be complicated, since the chamber layer and the nozzle layer are manufactured through separate processes. On the other hand, a method of fabricating the ink jet head in accordance with the monolithic type can create the chamber layer and the nozzle layer such that the nozzles are precisely aligned with the pressure generating elements. In addition, the monolithic type is capable of decreasing a manufacturing cost and improving productivity by virtue of simplifying the manufacturing process by forming the chamber layer and the nozzle layer by the same process. Examples of methods of fabricating the ink jet head in accordance with the monolithic type are disclosed in U.S. Pat. Nos. 5,478,606, 5,524,784, and 6,022,482.
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A height of the ink flow path is affected by a thickness of the chamber layer 106. Therefore, the thickness of the chamber layer 106 should be adjustable and precisely reproducible. In a method of fabricating the conventional monolithic ink jet head, in order to create the chamber layer 106 having a reproducible thickness, the chamber layer 106 is formed of a material layer having a polish selectivity (polishing rate of the sacrificial layer/polishing rate of the chamber layer) with respect to the sacrificial layer 108. In this case, the chamber layer 106 functions as a polish stop layer for detecting a polishing stop point of the CMP process. However, as described above, when both the chamber layer 106 and the sacrificial material layer 108 are formed of a resin material, it may be difficult to make the chamber layer 106 have a polish selectivity with respect to the sacrificial material layer 108. As a result, the chamber layer 106 does not function as the polish stop layer and is polished together with the sacrificial material layer 108, thereby making it difficult to adjust and precisely reproduce the thickness of the chamber layer 106. Additionally, although the sacrificial layer 108′ may be formed by applying and patterning the positive photoresist without employing the above-mentioned CMP process, it may be difficult to form the sacrificial layer 108′ having a flat top surface due to a step between the sacrificial material layer 108 and the chamber layer 106. This may make it difficult to form the ink flow path having uniform dimensions.
The present general inventive concept provides a method of fabricating an ink jet head having an ink flow path of uniform dimensions by forming a chamber layer having a precise and reproducible thickness.
Additional aspects and advantages of the present general inventive concept 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 general inventive concept.
The foregoing and/or other aspects and advantages of the present general inventive concept are achieved by providing a method of fabricating an ink jet head having a metal chamber layer. The method may include preparing a substrate having pressure-generating elements to generate pressure to eject ink. The metal chamber layer to define sidewalls of an ink flow path may then be formed on the substrate. A sacrificial layer is formed to fill a region where the ink flow path is to be formed between the sidewalls defined by the metal chamber layer. A nozzle layer having nozzles corresponding to the pressure-generating elements is then formed on the metal chamber layer and the sacrificial layer.
The pressure-generating elements may be heat-generating resistors.
The method may further include forming a seed layer pattern on the substrate before forming the metal chamber layer. In this case, the metal chamber layer may be formed on the seed layer pattern by an electroplating method. The seed layer pattern may be formed by forming a seed layer on the substrate and patterning the seed layer. The seed layer may be formed of a metal layer containing at least one metal selected from a group including copper, platinum, gold, palladium, silver, and nickel. The metal chamber layer may be formed of a copper layer or a nickel layer. Other metals may also be used to form the metal chamber layer.
The method may further include forming a sacrificial material layer on the substrate after forming the seed layer pattern thereon. The sacrificial material layer may be patterned to form a sacrificial material layer pattern to cover the region where the ink flow path is to be formed and to expose the seed layer pattern. In this case, forming the sacrificial layer may include polishing the sacrificial material layer pattern using the metal chamber layer as a polish stop layer. The sacrificial material layer may be formed of a positive photoresist. In addition, polishing the sacrificial material layer pattern may be performed by a chemical mechanical polishing (CMP) process.
Alternatively, forming the sacrificial layer may include forming the sacrificial material layer to cover the metal chamber layer disposed on the substrate, and polishing the sacrificial material layer using the metal chamber layer as a polish stop layer.
The foregoing and/or other aspects and advantages of the present general inventive concept may also be achieved by providing an ink jet head having a metal chamber layer. The ink jet head includes a substrate having pressure-generating elements to generate pressure to eject ink. A metal chamber layer defining sidewalls of an ink flow path is disposed on the substrate. A nozzle layer having nozzles corresponding to the pressure-generating elements is disposed on the metal chamber layer to define an upper surface of the ink flow path.
The pressure-generating elements may be heat-generating resistors. The metal chamber layer may be a copper layer or a nickel layer. Other metals may also be used to form the metal chamber layer.
The ink jet head may further include a seed layer pattern interposed between the substrate and the metal chamber layer. The seed layer pattern may be a metal layer containing at least one metal selected from a group including copper, platinum, gold, palladium, silver, and nickel.
These and/or other aspects and advantages 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:
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.
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A portion of the sacrificial material layer pattern 310′ that protrudes over a top surface of the metal chamber layer 312 may be removed by polishing. Polishing the sacrificial material layer pattern 310′ may be performed by the chemical mechanical polishing (CMP) process. In this case, the metal chamber layer 312 functions as a polish stop layer. As described above, the metal chamber layer 312 is formed of a metal layer, unlike the sacrificial material layer pattern 310′. The metal chamber layer 312 has a greater rigidity than the sacrificial material layer pattern 310′, which is formed of a resin layer such as a positive photoresist. A difference in rigidity makes the metal chamber layer 312 have a low polish selectivity with respect to the sacrificial material layer pattern 310′. The CMP process may be stably completed when the process reaches the top surface of the metal chamber layer 312. As a result, the metal chamber layer 312 is not polished together with the sacrificial material layer pattern 310′, and the thickness of the metal chamber layer 312 can be adjusted and precisely reproduced.
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The metal chamber layer 312 is disposed on the substrate 300 having the insulating passivation layer 306 thereon. The metal chamber layer 312 defines the sidewalls of the ink flow path. The seed layer pattern 308 is interposed between the substrate 300 and the metal chamber layer 312. The metal chamber layer 312 may be formed by an electroplating process using the seed layer pattern 308 as a conductive underlying layer. The metal chamber layer 312 may be a copper layer or a nickel layer. The seed layer pattern 308 may be a metal layer containing at least one metal selected from a group including copper (Cu), platinum (Pt), gold (Au), palladium (Pd), silver (Ag), and nickel (Ni). The nozzle layer 316 is disposed on the metal chamber layer 312. The nozzle layer 316 defines an upper surface of the ink flow path. The ink flow path includes the ink chambers 320 and the ink channels 322. In addition, the nozzle layer 316 includes the nozzles 316′ corresponding to the pressure-generating elements 302, respectively. The nozzle layer 316 may be a photo-curable resin layer or a thermosetting resin layer. In this case, the nozzle layer 316 may be an epoxy-based, a polyimide-based, or a polyacrylate-based resin layer.
A bottom surface of the substrate 300 is attached to an ink container (not shown). Ink in the ink container is supplied through the ink-feed passage 318 extending through the substrate 300 and via the ink channels 322 to the ink chambers 320 where it is temporarily stored. The ink stored in the ink chambers 320 is instantly heated by the heat generating resistors (i.e., the pressure-generating elements 302) to be ejected through the nozzles 316′ in a droplet shape by the pressure generated.
As can be seen from the foregoing, a method of fabricating an ink jet head in accordance with the present general inventive concept is provided with a chamber layer defining sidewalls of an ink flow path, the chamber layer being formed of a metal layer having a high polish selectivity with respect to a resin layer. As a result, the ink jet head having the ink flow path of uniform dimensions can be manufactured by forming the chamber layer having a precisely reproducible thickness.
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.
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10-2004-0066546 | Aug 2004 | KR | national |
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