Patent number 8557620 is assigned to
The following quote was obtained by the news editors from the background information supplied by the inventors: "Exemplary embodiments of the invention relate generally to flat panel displays. More particularly, exemplary embodiments of the invention relate to a method of manufacturing a display substrate and a liquid crystal display (LCD) apparatus using the display substrate.
"Generally, a liquid crystal display (LCD) panel includes a display substrate, an opposing substrate facing the display substrate, and a liquid crystal layer interposed between the display substrate and the opposing substrate. The display substrate includes a plurality of switching devices for driving pixels. The LCD panel applies a voltage to the liquid crystal layer to control light transmittance in order to display an image.
"The display substrate may be manufactured through a five-mask process that includes forming a gate pattern, forming a semiconductor pattern having a semiconductor layer and an ohmic contact pattern, forming a source pattern, forming a contact portion and forming a pixel electrode. Since manufacturing costs for masks are high, a four-mask process and a three-mask process have been developed in order to reduce the number of masks required for manufacturing the display substrate.
"When the display substrate is manufactured through a typical three-mask process, the semiconductor pattern and the source pattern are patterned through the same mask, and the contact portion and the pixel electrode are patterned through the same mask. As a result, two masks may be omitted in comparison to the five-mask process.
"When the display substrate is manufactured through the typical three-mask process, passivation layers may be excessively etched during photoresist lift off. Thus, the metal layers of the display substrate may be damaged. In order to solve the above-mentioned problems, a method of changing manufacturing conditions, a method of using negative photoresist and a method of structurally changing the contact portion and other such methods have been developed. However, the process margins for the above mentioned lift-off processes may not be sufficient. Therefore, there is a need for a method that enhances the reliability and the process margins for lift-off processes."
In addition to the background information obtained for this patent, VerticalNews journalists also obtained the inventors' summary information for this patent: "Example embodiments of the present invention provide a method of manufacturing a display substrate capable of improving the reliability and the process margin for a given lift-off process.
"Example embodiments of the present invention provide a method of manufacturing both a display substrate and a display apparatus using such a substrate.
"In one aspect of the invention, a method of manufacturing a display substrate comprises forming a gate line, a data line crossing the gate line, and a switching device on a base substrate, the switching device electrically connected to the gate line and the data line. A passivation layer, a first resist layer, and a second resist layer are then sequentially formed on the base substrate. Then, the first resist layer and the second resist layer are patterned to form a resist pattern and an etch-stop pattern, the etch-stop pattern having a sidewall protruding over a sidewall of the resist pattern. A portion of the passivation layer is removed, where the removed portion is exposed through the resist pattern and the etch-stop pattern, to form a contact hole on a drain electrode of the switching device. Finally, a pixel electrode is formed, where the pixel electrode is electrically connected to the switching device through the contact hole.
"In another aspect of the invention, a method of manufacturing a display apparatus comprises, on a first base substrate, forming a gate line, a data line crossing the gate line, and a switching device electrically connected to the gate line and the data line.
"sequentially forming a passivation layer, a first resist layer and a second resist layer on the first base substrate;
"patterning the first resist layer and the second resist layer to form a resist pattern and an etch-stop pattern, the etch-stop pattern having a sidewall protruding from a sidewall of the resist pattern;
"removing a portion of the passivation layer, which is exposed through the resist pattern and the etch-stop pattern, to form a contact hole on a drain electrode of the switching device;
"forming a pixel electrode electrically connected to the switching device through the contact hole; and
"forming a common electrode layer on a second base substrate, wherein the second base substrate is facing the first base substrate."
URL and more information on this patent, see: Hong, Pil-Soon; Park, Jung-In; Lee, Hi-Kuk. Method of Manufacturing a Display Substrate and Method of Manufacturing a Display Apparatus Using the Same. U.S. Patent Number 8557620, filed
Keywords for this news article include: Electronics, Semiconductor,
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