Fabrication method of thin film transistor

Abstract

The invention provides a manufacturing method of a thin-film transistor. The method comprises the steps of sequentially forming a semiconductor layer and a first grid insulating layer on a substrate; forming a photoresist pattern on the first grid insulating layer, wherein the photoresist pattern comprises a first photoresist layer and a second photoresist layer and the thickness of the first photoresist layer is larger than the thickness of the second photoresist layer; adopting the photoresist pattern as a mask, and etching the semiconductor layer and the first grid insulating layer for the first time; removing the second photoresist layer; etching the first grid insulating layer for a second time to remove the thickness of at least one part of the first grid insulating layer that is not covered by the first photoresist layer; removing the first photoresist layer; forming a second grid insulating layer on the first grid insulating layer; and forming a grid on the second grid insulating layer. Based on the above method for manufacturing the thin-film transistor, the sub-threshold swing for driving the thin-film transistor is increased. Meanwhile, the driving performance of an AMOLED is improved.

Description

technical field [0001] The invention relates to the technical field of semiconductors, in particular to a preparation method of a thin film transistor. Background technique [0002] Compared with LCD, AMOLED has shown obvious advantages in terms of energy consumption, color saturation, contrast, and flexible applications, and its market share has risen rapidly. In the pixel circuit of AMOLED, its thin film transistor can be divided into switch thin film transistor (Switch TFT) and driving thin film transistor (Driver TFT). Switch TFT, as a switch of a digital circuit, works in the off state and the on state in the post-threshold region. Considering product power consumption, PPI, switching speed, etc., the smaller the sub-threshold swing, the better. Driver TFT controls the current flowing through the OLED and works near the sub-threshold. In order to ensure the accurate display of each gray scale, its driving ability should not be too high. In the case of the same size, t...

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Problems solved by technology

However, with the increase of PPI, the layout space becomes more and more insufficient, and the large size of Driver TFT has become an important factor limiting the continued increase of PPI.

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