Fabrication of TFTs for LCD using 3‐mask process

Yoo, Sun-Kook; Cho, Heung‐Lyul; Kwon, O Yong; Nam, Seung‐Hee; Chang, Yoon‐Gyoung; Kim, Ki‐Yong; Cha, Soo‐Yeoul; Ahn, Byung‐Chul; Chung, In‐Jae

doi:10.1080/15980316.2005.9651979

Cited by 6 publications

(10 citation statements)

References 2 publications

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“…It has been disclosed in previous literature that the lift-off process could be successfully used with a conventional mask. 2 A thin passivation SiN x film was first deposited by PECVD on TFTs before the photolithography process. After that, the pad opening and TFT-source-contact-opening dryetch step was used for the removal of SiN x and GI passivation.…”

Section: Halftone Mask Designmentioning

confidence: 99%

“…It is well known that under a specific stripping period, a limited lift-off pattern size could be determined. 2 Figure 7 shows the result of a lift-off pattern size of 2000 µm 2 after a 120-sec chemical stripping process. Some ITO-covered P/R still remains on the glass substrate.…”

Section: Lift-off Enhancement Technologymentioning

confidence: 99%

“…Some ITO-covered P/R still remains on the glass substrate. The chemical stripper cannot completely lift-off ITO-P/R of a size larger than 2000-µm 2 . It is understandable that by increasing the chemical stripping path so as to minimize the ITO-P/R pattern area would greatly improve the chemical lift-off ability in a stripper machine.…”

Section: Lift-off Enhancement Technologymentioning

confidence: 99%

“…1 The ITO lift-off technique was recently integrated into a TFT fabrication process to further reduce the photolithography process. 2,3 Through the use of a new pixel structure redesign and by combining the ITO lift-off technology and the SiN x passivation process, we could reduce the two photolithography processes into one. However, compared to the conventional chemical lift-off process, we have to create a reverse-taper structure of a photo-developed P/R such that the P/R stripper could react at this undercutting region to lift-off ITO.…”

Section: Introductionmentioning

confidence: 99%

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ITO lift‐off technique for TFT mask‐reduction process

Fang¹,

Lin²,

Chen³

2009

J Soc Info Display

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Abstract— In recent years, reducing the number of TFT‐manufacturing steps has become an unavoidable technology development stream for all TFT‐LCD makers for the purpose of cost reduction. In this paper, an advanced photomask‐process‐reduction technique, a three‐mask TFT process, by chemical lift‐off which is inherent of the conventional four‐mask TFT fabrication process, is proposed. The major feature of this three‐mask technique is the combining of the passivation‐layer and pixel‐electrode formation within one photolithography process. A new halftone mask (HTM) design has been applied to the photolithography process. With this new HTM design, a small SiNx island bridge was formed, located at the TFT source contact‐edge border. And it provided an ITO pixel electrical conducting path and avoided the undercut issue where ITO breaks from the gate insulator (GI). In order to enhance the chemical lift‐off efficiency, different process and structure designs were also implemented and introduced. Furthermore, a new laser lift‐off technology was adopted to improve the ability of ITO lift‐off. By using this new laser lift‐off technology, unnecessary ITO film could be easily lift‐off before photoresist stripping. Finally, the first HTM lift‐off panel was successfully demonstrated by using our new three‐mask TFT design scheme.

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Section: Halftone Mask Designmentioning

confidence: 99%

Section: Lift-off Enhancement Technologymentioning

confidence: 99%

Section: Lift-off Enhancement Technologymentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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ITO lift‐off technique for TFT mask‐reduction process

Fang¹,

Lin²,

Chen³

2009

J Soc Info Display

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“…A liquid-crystal display (LCD) is organized into a number of parts, including backlights, polarizers, glass, liquid crystals, and color filters, each of which requires numerous unit processes for their manufacturing [1], [2]. In the early mass production stage, the most striking feature in terms of cost has been the high proportion of material and component costs, reaching approximately 70% to 75% of the total cost amount [3], [4].…”

Section: Introductionmentioning

confidence: 99%

Preliminary Works of Contact via Formation of LCD Backplanes Using Silver Printing

Yang¹

2013

ETRI J

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The fabrication of a thin‐film transistor backplane and a liquid‐crystal display using printing processes can eliminate the need for photolithography and offers the potential to reduce the manufacturing costs. In this study, we prepare contact via structures through a poly(methyl methacrylate) polymer insulator layer using inkjet printing. When droplets of silver ink composed of a polymer solvent are placed onto the polymer insulator and annealed at high temperatures, the silver ink penetrates the interior of the polymer and generates conducting paths between the top and bottom metal lines through the partial dissolution and swelling of the polymer. The electrical property of various contact via‐hole interconnections is investigated using a semiconductor characterization system.

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