Method of measuring length of lightly doped drain (LDD) region in array substrate

Abstract

The invention provides a method of measuring the length of a lightly doped drain (LDD) region in an array substrate. A strong alkaline solution is firstly used to corrode and exfoliate the source (251), the drain (252) of a TFT (Thin Film Transistor) (2) and the above film layer in a layer by layer mode; a strong acid solution is then used to corrode and exfoliate an interlayer insulation layer (24) and a gate insulation layer (22) which is not covered by a gate (23); and finally, an electron scanning microscope is used to photograph a down-looking image of the array substrate, and the length between the edge of the gate (23) and a boundary line between the lightly doped drain region (212) and a heavily doped region (213) on the down-looking image is measured, and the length is the actual length of the lightly doped drain region (212). The LDD doping process can be effectively monitored, and the stability and the reliability of products are enhanced.

Description

technical field [0001] The invention relates to the field of display device detection, in particular to a method for measuring the length of a lightly doped drain region in an array substrate. Background technique [0002] Thin Film Transistor (TFT) is the main driving element in current Liquid Crystal Display (LCD) and Active Matrix Organic Light-Emitting Diode (AMOLED). It is related to the display performance of the flat panel display device. [0003] Thin film transistors have various structures, and there are also various materials for preparing thin film transistors with corresponding structures. Low Temperature Polysilicon (LTPS) material is one of the more preferred materials. Due to the regular arrangement of atoms of low temperature polysilicon, the current carrying High sub-mobility. For voltage-driven LCDs, LTPS TFTs can use smaller TFTs to achieve deflection driving of liquid crystal molecules due to their high mobility, which greatly reduces the TFT occupation...

AI Technical Summary

Problems solved by technology

[0005] However, when producing LTPS array substrates, the existing production lines can only estimate the length of the LDD based on the length of the photoresist, but cannot perform the characterization and measurement of the actual product

like Figure 1a , Figure 1b ,and Figure 1c As shown, LDD is formed by doping polysilicon (poly-Si) with ions. After ion implantation into polysilicon, a small amount of diffusion will be carried out through the subsequent activation process. The actual length of LDD will have a certain deviation from the estimated value. Therefore, the existing method of estimating the length of the lightly doped drain region of the TFT in the LTPS array substrate cannot effectively monitor the LDD doping process.

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