Product Code: ICAL05_P501

Studies of Frequency-Tripled Nd:YAG Laser in Laser Structuring Process
Authors:
Bin Zhang, Hong Kong Poly University; Hong Kong
K.C. Yung, Hong Kong Poly University; Hong Kong
Presented at ICALEO 2005

With the increasing demand for finer lines/spaces on PCB boards, a new technology ?laser structuring ? has emerged in recent years. In this research, the frequency-tripled Nd:YAG laser is selected as the laser source in laser structuring; this laser is often used in miniaturization machining. This paper describes in detail the processing parameters? influences of lasers and etching process, such as laser power, repetitions, repetition rate, bite size and etching time, on laser structuring results. From the research results, it can be concluded that the line width and depth are increased with increases in the laser power and repetition times. Repetition rate, bite size and velocity are related to one another. When the bite size is fixed, the velocity increases with the repetition rate and the depth of the line is decreased at the same time. When the repetition rate is fixed, velocity increases with the bite size. Etching process is very important which will influence the quality of copper line. So some parameters during laser writing and etching process should be controlled to get copper circuit line with good quality. Two kinds of parameters were considered in this section. First, the parameters in laser structuring process which will influence the depth and width of copper space should be studied about their further influences on the quality of copper line. Second, the etching time that will influence the cross section of copper line directly should be studied. The smallest width of fine line achievable by laser structuring with frequency tripled Nd:YAG laser is also studied in this paper. The width of fine line is influenced not only by laser parameters, but also by etching process.