A method of manufacturing a thin film transistor

Abstract

A manufacturing method of a thin film transistor and a thin film transistor are provided. In the manufacturing method, formation of pattern of a source electrode (7), a drain electrode (8) and an active layer (6) comprises: forming a semiconductor layer (10) and a conductive layer (11) that cover the whole substrate on the substrate in sequence; forming a first photoresist layer (4) at a region where the source electrode is to be formed and at a region where the drain electrode is to be formed on the conductive layer (11), respectively; forming a second photoresist layer (5) at least at a gap between the source electrode and the drain electrode that are to be formed on the conductive layer (11); conducting an etching process on the substrate with the first photoresist layer (4), the second photoresist layer (5), the semiconductor layer (10) and the conductive layer (11) formed thereon, so as to form pattern of the active layer (6), the source electrode (7) and the drain electrode (8).

Description

technical field [0001] The invention relates to the technical field of manufacturing semiconductor devices, in particular to a method for manufacturing a thin film transistor. Background technique [0002] A thin film transistor (Thin Film Transistor, TFT) as a switching device plays an important role in the field of display technology. To make TFT with low cost and high performance has always been the goal pursued by people. [0003] Generally, a thin film transistor includes at least a gate (Gate), a source and a drain (Source and Drain, referred to as source and drain SD), and a channel layer (Channel, also referred to as an active layer) and the like. In recent years, in order to simplify the process flow or reduce the number of masks used, the semiconductor layer for the active layer pattern and the conductive layer for the source and drain patterns are deposited first, and then the gray tone mask (gray tone mask, referred to as GTM) or half tone mask (half tone mask,...

AI Technical Summary

Problems solved by technology

[0009] In recent years, with the trend of decreasing pattern line width, the distance between the source and drain is getting smaller and smaller, generally on the order of several microns, and the source and drain are easily short-circuited due to incomplete etching ( i.e. form GTBridge bad)

In addition, the active layer will also be damaged due to excessive etching, causing the active layer to be disconnected (that is, poor channel open)

In the prior art, a photoresist layer with different thicknesses in different regions is formed through a gray-tone mask or a half-tone mask. Due to the limitation of glue coating uniformity and exposure uniformity, the incompletely exposed region (that is, the region corresponding to the channel) is correspondingly fabricated. The thickness uniformity of the photoresist layer is difficult to control accurately, some areas are thinner and some areas are thicker, and the subsequent etching is carried out according to the condition of equal thickness, which leads to incomplete etching of the photoresist in the thicker area , resulting in poor source-drain short circuit (GT Bridge), and excessive etching of the photoresist in the thinner area, resulting in poor channel open when the TFT is energized

Seriously affect the working performance of TFT, or cause the defect of TFT, so that the yield rate of mass-produced TFT will drop

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