In this paper, a novel PZT film patterning method by femtosecond laser is proposed. The method is different from traditional dry-etching and wet-etching technology. Femtosecond laser microfabrication technology has several advantages such as high resolution, no mask direct-writing and seldom-heating, etc. A two-layer (PZT thin film and substrate) heating and ablating threshold model is built and the relationship of PZT/Si two-layer system micro ablation morphology depending on laser pulse energy is constructed. From the model and experiment data, we obtain the suitable energy region to pattern PZT film freely without damage Si substrate. A 3μm resolution of PZT pattern is achieved in our experiment. In order to verify the fabrication available of this technology, several micro functional devices are successfully patterned by optimized femtosecond pulsed laser energy and their function are detected. The results prove that the PZT patterning quality is good.
ABSTRACTA laser direct writing system has been developed for low temperature deposition of WSix on TiN from a gas mixture of WF6 and SiH4-. An Ar+ laser (488 nm, 1.5 W) and a diode laser (796 nm, 1.0 W) are used as photon sources. Lines are written at scan speeds of up to 100 μ/s from a flowing gas mixture of WF6 and SiH4 diluted in Ar. Lines 1.5 to 11 nm wide and 20 to 180 nmthick are obtained at a writing speed of 100 μ/s with the Ar+ laser. Lines written using the diode laser are typically 4 to 12 μm wide and 160 to 860 nm thick. W/Si ratio in the deposits, as measured by Auger electron spectroscopy (AES), isbetween 1.5 and 1.8.Surface analysis of the interaction of this gas mixture with the TiN surface without laser irradiation shows that W, Si and F are adsorbed on the surface when exposed simultaneously to WF6 and SiH4 producing an adsorbed layer where W/Si ratio is 1.3 and F/W ratio 1.7.
AbstractWe have developed a compact and inexpensive laser direct writing system, based on the 796 nm radiation of a 1 W diode laser array for the deposition of tungsten silicides. The laser power incident on TiN substrates varies between 50 and 550 mW. Lines are deposited from a gas mixture of WF6 and SiH4, whose total pressure is kept below 15 Torr to avoid uncontrolled reactions. Experiments are performed in a static reactor with WF6/SiH4 ratios varying from 0.2 to 10. Lines written at speeds ranging from 2 to 100 μm/s have typical thicknesses and widths varying from 30 to 1000 μm and from 4 to 15 μm respectively. Auger Electron Spectroscopy (AES) shows that no fluorine is incorporated in the WSix film, within the limit of detection. Moreover, no oxygen, carbon or nitrogen are detected in the bulk, although some surface contamination is present. From AES measurements, the W/Si ratio is estimated to be between 1.1 and 1.4 for a reactive gas mixture of WF6: SiH4 (1: 3).
A Novel Laser Direct Writing System Integrated with A&F XXY Alignment Platform for Rapid Fabrication of Flexible Electronics