| Metal film is widely used in MEMS device manufacturing, aerospace technology, precision instrument manufacturing and circuit board processing. There are many methods of making microstructures on metal thin film. In this paper, theoretical analysis and experimental researchs are done on laser processing technology to produce micro-structure on copper film.In this paper, we put forward a variety of experimental methods for actual demand. The main work of this paper includes the following sections:1. Analyze the principle of laser-material interaction from theoretical point of view. Describes metal reflection and absorption of the laser. Use dual-temperature model to describe the heat propagation in the material. We find that the logarithm of energy and square of the diameter of ablated spots has a linear relationship from the formula of laser fluence. Derive the model of moving spots ablating matel film by cumulative model.2. Design and establish the ultraviolet nanosecond laser processing system based on solid-state laser whose wavelength is 355 nm. The core of motion control system is PMAC. PMAC transmmits signals by expansion card to control the moving motion of stage. Software on personal computer controls the laser parameters and PMAC signal via the communication interface. The system achieves coordinated control of laser and motion of stage.3. Use the ultraviolet nanosecond pulsed laser processing system to ablate copper film whose thickness is 200 nm. The experiment is divided into two parts: single pulse ablating copper film and direct-write linear structure. Ablation experiments show the relation of the laser pulse energy and the spot diameter, and the parameters to get better processing results. Experiments are carried on which copper film is also placed outside focus plate. It was found that the processing effect is more ideal when the copper film at a certain distance from the focal plane. This processing method is more suitable for processing a larger size microstructure. |
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