Evaluation of laser-assisted Scribing and Drilling performance using Ytterbium laser for semiconductor materials

• Main Authors: Raunak Joshi, 羅傑
• Other Authors: Yang, Hung-Chi
• Format: Others
• Language: en_US
• Published: 2018
• Online Access: http://ndltd.ncl.edu.tw/handle/j4aah2

碩士 === 南臺科技大學 === 電機工程系 === 106 === Laser scribing and drilling of materials plays a critical factor in semiconductor, electronics and packaging industry. Research and development in these industries are booming since last decade. Lasers used in the industries are very expensive and requires very high maintenance. Along with these problems, the efficiency of the laser is lower than the price paid for it. The main factors for considering the availability of different types of lasers are scribing and drilling. Power, frequency and wavelength of the laser are key factors to carry out scribing and drilling process on different types of material. The main purpose of this thesis is to propose a new model which could replace the existing system keeping the efficiency, cost of production and maintenance in consideration. Ytterbium laser possesses better features because of its higher efficiency and low cost. Along with these advantages, there are a few disadvantages associated with it. This thesis will tackle these problems during the system setup. The main problem with ytterbium laser is alignment as this laser belongs to infrared region and is not visible to human eyes. Alignment of the laser is important because it is directly proportional to the efficiency of the laser. The proper alignment shows a significant increase in efficiency and could be vice versa. A new property of ytterbium laser has been found during the alignment process in this thesis. Ytterbium laser when comes in contact with aluminum nitride produces a green light because of reaction between laser and surface of aluminum nitride. As ytterbium laser is invisible, this property helped us to know the exact position of laser and also helped in the alignment process. This thesis also compares experimental results between ytterbium and diode pumped solid state laser. The wavelength of ytterbium laser is 1064 nm and the wavelength of diode pumped solid state laser is 355 nm. Laser with higher wavelength possesses wider beam width. Scribing and drilling experimental results is the base for comparison between lasers. Ytterbium laser is proved to have several advantages over diode pumped solid state laser. First, Ytterbium laser is cheaper and requires less maintenance than conventional laser. The other is that its laser beam with higher wavelength can scribe deeper into opaque materials like aluminum nitride and silicon. Experiments are conducted with two different types of laser. As a result, ytterbium laser proved to have better depth and width. It could also be used for drilling applications which were not possible with diode pumped solid state laser. In this thesis, we explore the correlation between the transparency of an object and the wavelength. When the wavelength of the laser is in infrared zone there is no reflection at surface of the wafer.