Wafer Dicing

The answer is not simple. For pulsed lasers with the same average power and repetition rate, the speed and quality of a dicing process can vary widely due to the strong influence of other laser characteristics such as pulse duration and wavelength. For example, while longer pulse widths and longer wavelengths will generally cut faster, they are also more likely to cause excessive melting and cracking. Shorter pulse widths (ps, fs) and shorter wavelengths (UV, DUV) deliver the best quality results with minimal HAZ (heat affected zone) and higher die strength, but at a higher cost and lower system throughput. With these considerations, many in the industry have found short ns-pulse 355 nm Q-switched laser systems to be ideal for wafer scribing and dicing applications.

Today’s laser products offer ever-higher power levels, and this holds true even for short-ns pulse widths and 355 nm wavelength. With this trend, the challenge increasingly becomes using this higher power and pulse energy as efficiently as possible. In Spectra-Physics’ Industrial Laser Applications Lab, we have examined experimentally the efficiency advantage of line-focus fluence optimization for thin silicon dicing. We have shown that even with the high-quality of short pulse and short-wavelength processing, exceptionally high cutting speeds are still possible, as highlighted in the table below.

Wafer Thickness	Approximate Cutting Speed
25 μm	2000 mm/sec
50 μm	1000 mm/sec
75 μm	600 mm/sec
100 μm	375 mm/sec

The low ablation threshold, a direct result of the short pulse width, combined with line-focus fluence optimization delivers high-quality short-pulse, short-wavelength machining at industrial-scale process speeds.

Spectra-Physics supplies lasers for semiconductor and LED manufacturing across a broad range of precision applications. Our semiconductor lasers are proven in a wide range of semiconductor and LED applications including silicon wafer scribing and dicing. With thousands of UV lasers deployed in semiconductor and LED manufacturing worldwide, Spectra-Physics offers a broad portfolio of reliable, cost-effective lasers backed by a global support organization.