Journal of the Microelectronics and Packaging Society (마이크로전자및패키징학회지)

The Korean Microelectronics and Packaging Society (한국마이크로전자및패키징학회)
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An investigation on dicing 28-nm node Cu/low-k wafer with a Picosecond Pulse Laser

  • Hsu, Hsiang-Chen (Department of Mechanical and Automation Engineering, I-Shou University) ;
  • Chu, Li-Ming (Department of Mechanical Engineering, Southern Taiwan University of Science and Technology University) ;
  • Liu, Baojun (Department of Mechanical Engineering, University of Electronic Science and Technology of China) ;
  • Fu, Chih-Chiang (Department of Mechanical and Automation Engineering, I-Shou University)
  • Received : 2014.12.01
  • Accepted : 2014.12.19
  • Published : 2014.12.30
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Abstract

For a nanoscale Cu/low-k wafer, inter-layer dielectric (ILD) and metal layers peelings, cracks, chipping, and delamination are the most common dicing defects by traditional diamond blade saw process. Sidewall void in sawing street is one of the key factors to bring about cracks and chipping. The aim of this research is to evaluate laser grooving & mechanical sawing parameters to eliminate sidewall void and avoid top-side chipping as well as peeling. An ultra-fast pico-second (ps) laser is applied to groove/singulate the 28-nanometer node wafer with Cu/low-k dielectric. A series of comprehensive parametric study on the recipes of input laser power, repetition rate, grooving speed, defocus amount and street index has been conducted to improve the quality of dicing process. The effects of the laser kerf geometry, grooving edge quality and defects are evaluated by using scanning electron microscopy (SEM) and focused ion beam (FIB). Experimental results have shown that the laser grooving technique is capable to improve the quality and yield issues on Cu/low-k wafer dicing process.

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