Laser annealing apparatus and annealing method

Abstract

When a laser bean temporally modulated in amplitude by a modulator is shaped into a long and narrow beam by a beam shaper, the scanning-direction size of the long and narrow beam shaped by the beam shaper is selected to be in a range of from 2 to 10 microns, preferably in a range of from 2 to 4 microns and the scanning speed of the beam is selected to be in a range of from 300 to 1000 mm / s, preferably in a range of from 500 to 1000 m / s. As a result, damage of the silicon thin film can be suppressed while energy utilizing efficiency of the laser beam can be improved. Accordingly, laterally grown crystals (belt-like crystals) improved in throughput can be obtained on a required region of a substrate scanned and irradiated with the laser beam.

Description

technical field [0001] The present invention relates to a laser annealing method and a laser annealing device suitable for irradiating laser light on an amorphous semiconductor film or a polycrystalline semiconductor film formed on an insulating substrate to improve film quality, expand crystal grains, or perform single crystallization. Background technique [0002] Currently, display devices such as liquid crystal display devices and organic EL display devices form images by switching pixel transistors (thin film transistors) formed of an amorphous or polysilicon film on a substrate such as glass or fused silica. If it is possible to simultaneously form a driver circuit for driving pixel transistors on this substrate, it is possible to drastically reduce manufacturing costs and improve reliability. However, when the silicon film forming the active layer of the transistor (thin-film transistor) constituting the driver circuit is amorphous, the performance of the thin-film tr...

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Problems solved by technology

[0005] In order to shape solid-state lasers such as the second harmonic of the continuous oscillation YAG laser used in the above-mentioned prior art into a slender shape, a multi-lens array or kaleidoscope with a complex structure, or rotational diffusion to reduce coherence (coherence) is used The plate acts as a homogenizer (beam shaper), so the energy loss is large

[0006] In addition, the short direction of the laser beam is shaped into a slender shape of about 20 microns, and the desired area is irradiated at a scanning speed of about 100 mm / s. However, the range of energy conditions for obtaining good laterally grown crystals is narrow, and energy fluctuations are easy to occur. damage to the silicon membrane

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