Method for making and using a test sample for measuring the length of a lightly doped drain region

Abstract

The invention provides a preparation method and a use method for a test sample used for measuring the length of a lightly doped drain. According to the preparation method, light resistance (7) on an interlayer insulation layer (6) is subjected to exposure and development to ensure that the light resistance (7) above a lightly doped drain (33) and the periphery of the lightly doped drain is removed by development, then the residual light resistance (7) is taken as a shielder, the interlayer insulation layer (6) and a gate insulation layer (4) are subjected to dry etching, and a gate (5), the lightly doped drain (33) and at least part of a heavily doped region (32) connected with the lightly doped drain (33) are exposed; and a vertical view image of the test sample is shot by using an electron scanning microscope in a production line, and the length, namely, the actual length of the lightly doped drain (33), from the edge of the gate (5) to a boundary line of the lightly doped drain (33) and the heavily doped region (32) is measured on the vertical view image, so that a doping process of the LDD (Lightly Doped Drain) can be effectively monitored in the production line, and the product stability and reliability are improved.

Description

technical field [0001] The invention relates to the field of display device detection, in particular to a method for manufacturing and using a test sample for measuring the length of a lightly doped drain region. 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 Poly-silicon (LTPS) material is one of the more preferred ones. 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 proportion of TFTs. It can increase the light transmission area and obtain higher brightne...

AI Technical Summary

Problems solved by technology

[0006] 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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