Pixel structure of thin film transistor liquid crystal display and manufacturing method thereof

Abstract

The invention discloses a pixel structure of a thin film transistor liquid crystal display and a manufacturing method thereof, which aim to reduce the number of mask, simplify process flow and save cost. The method comprises the following steps of sputtering a pixel electrode film and a passivation insulating layer film on a substrate in sequence; performing mask exposure by using a first mask plate and then etching the first mask plate to form a pixel electrode, passivation insulating layer and drain electrode through hole; and then sputtering source, drain electrode films and an ohmic contact layer film in sequence; performing mask exposure by using a second mask plate and etching the second mask plate to form a source electrode, a drain electrode, a source-drain channel and an ohmic contact layer covering on the source electrode and the drain electrode; and then sputtering an active layer film, an insulation layer film and a grid electrode film in sequence; performing mask exposure by using a third mask plate and etching the third mask plate to form an active layer, an insulation layer, a grid electrode and a source electrode driving hole. The invention synchronously discloses the pixel structure of the thin film transistor liquid crystal display.

Description

technical field [0001] The present invention relates to the technical field of liquid crystal displays, in particular to a pixel structure of a thin film transistor liquid crystal display (TFT-LCD) and a manufacturing method thereof. Background technique [0002] In recent years, TFT-LCD has dominated the flat panel display market due to its advantages of small size, light weight, low power consumption and no radiation. The TFT-LCD display forms an array of hundreds of thousands to millions of pixels, wherein each pixel is controlled by a thin film transistor (Thin Film Transistor, TFT) to display an image. [0003] The commonly used TFT at this stage is a bottom-gate structure using a 5-time mask (5Mask) process, and its structure is shown in the attached figure 1 As shown, the specific processing process is as follows: firstly, the gate metal thin film is prepared on the array glass substrate by magnetron sputtering, the exposure process and the chemical etching process a...

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Problems solved by technology

[0005] Whether it is a 5Mask process or a 4Mask process, the etching requirements for the ohmic contact layer in the channel area are relatively high. If the etching is not enough, the ohmic contact layer cannot be cut off, resulting in poor contact. Excessive etching will cause a-Si faults, and the process control is difficult.

Secondly, a-Si is a light-sensitive material. In the bottom-gate structure, the conductive channel is located on the uppermost layer of the TFT. Therefore, during the use of TFT-LCD, the external light is easy to shine on the a-Si at the position of the conductive channel. In terms of materials, it affects the retention characteristics of TFT-LCD, and severe image flicker or gray level changes will occur

In addition, in order to prevent light leakage, the black matrix on the color filter glass substrate needs to have a certain overlap with the pixel electrode area of ​​the TFT on the array glass substrate. However, this overlap reduces the aperture ratio of the TFT-LCD and affects the display effect.

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