Some Research On Laser Micromachining Applied In Electronic Industry

Laser, nuclear power and semiconductor as well as computer are called the four great inventions in the 20th century and have profound influence on human society. Integrated with modern computer numerical control technology, laser micromachining owns unparalleled predominance over traditional machining technology.Some applications of laser micromachining in electronics field are explored in this paper. We mainly study the application of laser machining in three subjects: frequency adjustment of quartz crystal, dielectric-loaded quadrifilar helix antenna for GPS and high density processing of flexible printed circuit board. The achievements include:1. We studied frequency adjustment of quartz crystal by laser micromachining and optimized laser parameters so that this technology can be applied in practice.Traditionally electrodes of quartz are thickened to make frequency down to expected value by vacuum film-coating or ion etching which is inefficient and costly. What's worse, it may reduce the reliability of product. In this paper, laser etching technology is applied in frequency adjustment of quartz crystal. This paper gives emphasis on how working current and Q pulse width influence the adjustment. We found appropriate working current and Q pulse width for the first time. Under this optimized parameter, the resonance frequency will be adjusted linearly with little effect in other parameters.2. A new technology of fabrication of dielectric-loaded quadrifilar helix antenna by sputtering and laser micromachining.The GPS antenna plays an important role in receiving and sending RF signal. It contains a cylinder of ceramic with four helix arms on the surface. Unlike planar microstrip antenna, quadrifilar helix antenna can't be made by traditional lithography for its three-dimensional structure. We solved the problem by sputtering and laser micromachining successfully.Also, we designed and simulated feed network in ADS software and fabricated it by laser etching technology. The amplitude of main S parameter was between 0.433 and 0.467 while ideal value was 0.5. The test result of the antenna samples reached the design requirements basically.3. Directly generation of circuit pattern by laser micromachining.Flexible copper clad laminate(FCCL) is widely used in CSP,MCM and COF. Traditional lithography technology has deficiency of high cost,low efficiency and pollution.We have developed a new green way to fabricate high density FCCL circuit pattern rapidly and cheaply. Taking advantage of different optical properties between copper and polyimide, unwanted copper film on polyimide is cut by very thin laser beam without damage to polyimide substrate and thus we get high density FCCL circuit pattern. This technology is simple,quick and pollution-free.Also, we have developed a new way to fabricate circuit pattern on transparent substrate by laser. The innovation of this method is that it merges film-coating with film-shaping. We can directly generate expected circuit pattern rapidly and cheaply. No similar method has been reported up to now.