High speed, laser-based marking method and system for producing machine readable marks on workpieces and semiconductor devices with reduced subsurface damage produced thereby
First Claim
1. A method of laser marking semiconductor wafers comprising:
- generating a pulsed laser beam, the beam having a laser pulse with a wavelength, pulse width, repetition rate, and energy; and
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 having a mark depth, wherein the pulse width is less than about 50 ns, and wherein the step of irradiating irradiates over the spot diameter to produce a mark having a mark depth substantially less than about 10 microns wherein undesirable subsurface damage to a semiconductor wafer is avoided.
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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
14 Claims
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1. A method of laser marking semiconductor wafers comprising:
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generating a pulsed laser beam, the beam having a laser pulse with a wavelength, pulse width, repetition rate, and energy; and
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 having a mark depth, wherein the pulse width is less than about 50 ns, and wherein the step of irradiating irradiates over the spot diameter to produce a mark having a mark depth substantially less than about 10 microns wherein undesirable subsurface damage to a semiconductor wafer is avoided. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 14)
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13. A semiconductor device having a machine readable mark with a depth of about 3-4.5 microns.
Specification