Ultraviolet Nanosecond Laser-induced Forward Transfer Technology And Application Research

With the advent and development of laser, laser machining technology has beengotten more and more attention and research. Due to narrow pulse width, high peakpower, good laser coherence and high repetition frequency, nanosecond, picosecondand femtosecond pulse lasers have been widely used in micromachining field, such asMEMS devices, microsensor, optical devices, etc.Laser induced forward transfer technology (LIFT) has developed as a new typeof laser machining technology in recent years. Its process is that a high-energy laserpulse goes through a transparent support substrate to focus on a thin film coated on it,and then the film is heated to melt state, and transferred to a nearby acceptor substrateat liquid. It is a novelty manufacturing technology, which can fast deposit specialmicropatten or microstructure on solid surface. It has a good development prospect inmany fields, such as integrated circuit processing and restoration, microoptical&electronic devices fabrication and so on. Different lasers have been used inLIFT, such as excimer laser, Nd: YAG laser, femtosecond laser etc. But ultravioletns-LIFT research and reports are seldom.Ultraviolet nanosecond pulse diode pumped solid-state laser (DPSSL) have theadvantages of short pulse width, high energy density, etc. In the dissertation ananosecond pulse laser forward transfer experiment system is designed with DPSSL,and some of LIFT experiments were done using metal material as samples. The mainwork in this dissertation is as follows:1. In the dissertation the interaction mechanism between ultraviolet nanosecondpulse laser and metal materials was studied. The relationship between the thermaldamage threshold and etching depth of Cu, Al, Ni three kinds of metal materialsand the function of single pulse energy and pulse number was analyzed. Theablation energy threshold and etching depth of the three kinds metals werecalculated at irradiated by pulse laser with wavelength355nm, pulse width40ns.2. An ultraviolet nanosecond pulse laser induced forward transfer experimentalsystem was constructed. The system mainly consisted of nanosecond laser source,optical route mechanical structure,3D motion platform, motion control systembased on PMAC, PC operational interface, etc. PMAC (programmable multi-axis controller) used as the core of motion control in the system, and formed the“PC+PMAC” structure. Under the Windows XP development environment, PCsoftware interface was designed by the development tool Visual C++6.0, whichcould manage and control the laser machining process.3. Three kinds of thickness copper thin films were coated by vacuummagnetron sputtering coating technology. With copper thin film as donor film andsilicon wafer as accept substrate, experiments of copper film LIFT were done.The influence of different processing parameters (such as laser energy, pulsenumber, transfer space, film thickness) on the transfer effect were studied and theresults were analyzed.