High speed, laser-based marking method and system for producing machine readable marks on workpieces and semiconductor devices with reduced subsurface damage produced thereby
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Abstract
An improved method of laser marking semiconductor wafers is provided wherein undesirable subsurface damage to a silicon semiconductor wafer is avoided while providing a relative improvement in marking speed for a predetermined spot diameter. A laser pulse of a laser beam has a predetermined wavelength, pulse width, repetition rate, and energy. The method further includes irradiating a semiconductor wafer with the pulsed laser beam over a spot diameter to produce a machine readable mark on the semiconductor wafer. The mark has a mark depth. The pulse width is less than about 50 ns, and the step of irradiating irradiates over the spot diameter to produce a mark having a mark depth substantially less than about 10 microns.
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Citations
28 Claims
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1-14. -14. (canceled)
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15. A method of laser marking a semiconductor wafer, the method comprising:
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generating a laser output for wafer marking, the output comprising at least one pulse having a pulse width less than about 50 nanoseconds, a wavelength, and at least one energy characteristic; and
irradiating the semiconductor wafer with the output over at least one spot having a diameter to produce a machine readable mark on the wafer, the mark having an average mark height, an average mark depth substantially less than about 10 microns, and wherein undesirable subsurface damage to the semiconductor wafer is avoided. - View Dependent Claims (16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28)
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Specification