An investigation on dicing 28-nm node Cu/low-k wafer with a Picosecond Pulse Laser
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For a nanoscale Cu/low-k wafer, inter-layer dielectric (ILD) and metal layers peelings, cracks, chipping, anddelamination are the most common dicing defects by traditional diamond blade saw process. Sidewall void in sawingstreet 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-fastpico-second (ps) laser is applied to groove/singulate the 28-nanometer node wafer with Cu/low-k dielectric. A series ofcomprehensive parametric study on the recipes of input laser power, repetition rate, grooving speed, defocus amount andstreet index has been conducted to improve the quality of dicing process. The effects of the laser kerf geometry, groovingedge 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 onCu/low-k wafer dicing process.
Abstract
For a nanoscale Cu/low-k wafer, inter-layer dielectric (ILD) and metal layers peelings, cracks, chipping, anddelamination are the most common dicing defects by traditional diamond blade saw process. Sidewall void in sawingstreet 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-fastpico-second (ps) laser is applied to groove/singulate the 28-nanometer node wafer with Cu/low-k dielectric. A series ofcomprehensive parametric study on the recipes of input laser power, repetition rate, grooving speed, defocus amount andstreet index has been conducted to improve the quality of dicing process. The effects of the laser kerf geometry, groovingedge 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 onCu/low-k wafer dicing process.
참고문헌 (12)
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