TFT mask reduction
AssigneeApple Inc.
InventorsMing-Chin Hung, Youngbae Park, Chun-Yao Huang, Shih Chang Chang, John Z. Zhong
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Abstract
Embodiments of the present disclosure relate to display devices and methods for manufacturing display devices. Specifically, embodiments of the present disclosure employ a halftone photoresist layer useful for reducing a number of masks needed to manufacture TFT backplane (e.g., thin-film transistors (TFTs) with fringe-field shifting). The halftone photoresist layer defines two areas, one defining an etching area for a first layer (e.g., a common voltage layer) and the other defining an etching area for a second layer (e.g., an organic passivation layer).
Claims24
A method, comprising:
- applying a photoresist layer to a display panel TFT backplane, wherein the photoresist layer is configured to define a pattern having:
- a first area useful for etching a first layer of the display panel TFT backplane;
- a second area patterned laterally around the first area useful for etching a second layer of the display panel TFT backplane;
- and
- a third area laterally around the second area where none of the photoresist layer is removed.
A method, comprising:
- depositing a photoresist layer on display panel TFT backplane;
- aligning a photomask with the photoresist layer;
- developing and removing portions of the photoresist layer through use of the photomask to create a halftone pattern over first and second portions of first and second layers of the display panel TFT backplane to be etched away, wherein creating the halftone pattern comprises:
- removing all material in the photoresist layer in a center portion of the halftone pattern of the photoresist layer to define the first portion to be etched away, and
- partially removing some of the material in the photoresist layer in lateral portions of the halftone pattern of the photoresist layer surrounding the center portion, while retaining all of the material in the photoresist layer in portions of the photoresist layer surrounding the lateral portions of the halftone pattern, to define the second portion to be etched away.
A method, comprising:
- manufacturing an electronic display device using a single photomask to pattern two layers of TFT backplane of the electronic display device, wherein the two layers are etched with different etching areas, wherein the photomask comprises a pattern having:
- a first area useful for etching a first layer of the two layers;
- a second area patterned laterally around the first area useful for etching a second layer of the two layers;
- and
- a third area laterally around the second area where none of the photoresist layer is removed.
Dependencies are inferred from the claim text.