New techniques for cutting silicon are now available using an Oxford Lasers micromachining system.
· High quality cut with minimal heat affected zone
· High process speeds
· Strong absorption
· High peak power
The interaction between the visible laser light and the silicon offers distinct advantages over conventional technologies. High precision cutting with minimal heat affect is possible, due to a unique combination of laser characteristics, including: visible wavelength, high beam quality, low pulse energy, very high repetition rate, short pulse width and high average power.
The visible fundamental laser wavelengths are strongly absorbed by silicon. For example – in 1mm, 66% of the incident power of a green laser will be absorbed. In contrast, only 1% of the power of a 1064 nm YAG will be absorbed in the same thickness.
The high peak power used is also a critical parameter. This is in the order of 50kW to 500kW and results in very efficient material vaporisation, with negligible thermal shock and consequent cracking.
In combination with the wavelength and high peak power, the high pulse repetition frequency used, typically 2kHz to 20kHz, produces a very high cutting speed.