Excimer laser annealing temperature control system and method, and annealing device

Abstract

The invention discloses an excimer laser annealing temperature control system and method and an annealing device. The control system comprises an objective table, a heating device, a cooling device and a PLC controller, wherein the heating device and the cooling device are alternately arranged below the objective table, and the PLC controller is connected with the heating device and the cooling device, respectively; a plurality of temperature sensors arranged respectively corresponding to the heating device and the cooling device are arranged on the lower surface of the objective table; and the PLC controller is used for receiving temperature signals of the objective table sent by the temperature sensors in real time, making comparison on the received temperature signals and a preset temperature value and respectively sending control signals to the heating device and the cooling device to drive the heating device and the cooling device to work. By utilizing a ''checkerboard type'' distributed temperature gradient, the temperatures difference between a fixed area region and four sides are constant, polycrystalline silicon in a fusion state is driven to grow at almost the same velocity in each direction so as to obtain large-size polycrystalline silicon grains, meanwhile, particles and bulges are reduced, and the surface roughness of a film layer is reduced after annealing, so that the electric properties of a TFT switch are well guaranteed.

Description

technical field [0001] The invention relates to the technical field of liquid crystal displays. More specifically, it relates to an excimer laser annealing temperature control system and method, and an annealing device. Background technique [0002] The annealing chamber currently used in traditional excimer laser annealing (ELA) only provides a carrier substrate to complete the irradiation of amorphous silicon thin films, and does not involve consideration of how to accurately control the growth direction of polysilicon, particle size and protrusion height, thereby affecting the electrical properties of thin film transistors. characteristics; since the current excimer laser beam is uniformly irradiated on the amorphous silicon thin film layer, the temperature of each part of the amorphous silicon thin film layer is roughly equal, so the starting point and direction of recrystallization cannot be controlled, resulting in crystallization of polysilicon after crystallization. ...

AI Technical Summary

Problems solved by technology

[0002] The annealing chamber currently used in traditional excimer laser annealing (ELA) only provides a carrier substrate to complete the irradiation of amorphous silicon thin films, and does not involve consideration of how to accurately control the growth direction of polysilicon, particle size and protrusion height, thereby affecting the electrical properties of thin film transistors. characteristics; since the current excimer laser beam is uniformly irradiated on the amorphous silicon thin film layer, the temperature of each part of the amorphous silicon thin film layer is roughly equal, so the starting point and direction of recrystallization cannot be controlled, resulting in crystallization of polysilicon after crystallization. The grains are too small, and the grain boundaries between grains are too much, which seriously affects the electron mobility of polysilicon.

[0003] During the crystallization of ELA, due to the rapid temperature loss under the action of nitrogen environment, the grain growth time is short, and the protrusion increases after crystallization, which can reach Left and right, such a surface shape will lead to: excessively high grain boundaries will cause breakdown of the gate insulating layer, resulting in short circuit between the gate and channel film layer, which can cause poor bright spots at the back end, etc., and the subsequent dry etching cannot The polysilicon protrusions are completely etched away, which affects the thickness of the subsequent gate oxide layer and the coverage of the steps, mainly affecting the electrical properties of the TFT.

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