Enhancement of ultraviolet laser ablation and etching organic solids
First Claim
1. A method of ablating a portion of a substrate, comprising the steps of:
- exposing said substrate to a first radiation pulse at a first ultraviolet wavelength; and
exposing said substrate to a second radiation pulse at a second, longer ultraviolet wavelength, at least one of said first or second radiation pulses being of sufficient energy fluence to exceed the threshold for ablative photodecomposition of said substrate.
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Accused Products
Abstract
A method and apparatus are described which enhance the ablative effect of a UV laser. The ablative effect of a pulsed UV laser is enhanced using a second, longer wavelength pulsed laser. Each pulse of the first laser is followed by or combined with a pulse from the second laser. The etch depth per pulse is controlled by varying the time between pulses from the first and second lasers. The maximum etch depth per pulse occurs at a time separation which is a function of the substrate being etched. The first laser wavelength is selected to be within the absorption spectrum of the unexcited surface molecules of the substrate, while the wavelength of the second laser is selected to be within the absorption spectrum of the surface molecules excited by the incident radiation of the first laser.
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Citations
30 Claims
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1. A method of ablating a portion of a substrate, comprising the steps of:
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exposing said substrate to a first radiation pulse at a first ultraviolet wavelength; and exposing said substrate to a second radiation pulse at a second, longer ultraviolet wavelength, at least one of said first or second radiation pulses being of sufficient energy fluence to exceed the threshold for ablative photodecomposition of said substrate. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. A method of etching a portion of a substrate, comprising the steps of:
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irradiating said portion of said substrate with a first pulse of ultraviolet radiation for a time sufficient to cause a transient change in the absorption characteristics of said portion of said substrate; and irradiating said portion of said substrate with a second pulse of longer wavelength ultraviolet radiation with sufficient energy fluence to cause ablative photodecomposition of said portion of said substrate. - View Dependent Claims (14, 15, 16, 17, 18, 19)
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20. A method of ablatively photodecomposing polymers and biological layers without substantial thermal effects wherein:
photodecomposition is accomplished by irradiating said layers with multiple wavelength radiation of sufficient energy fluence to exceed the threshold of ablative photodecomposition of said layers, at least one of said wavelengths being in the ultraviolet range. - View Dependent Claims (21, 22, 23)
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24. A method of etching a portion of a substrate, comprising the steps of:
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irradiating said portion of said substrate with a first radiation pulse whose wavelength is within the absorption spectrum of said substrate; irradiating said portion of said substrate with a second, longer wavelength radiation pulse at a predetermined time after irradiating the substrate with said first radiation pulse; at least one of said pulses having sufficient energy fluence to exceed the threshold for ablative photodecomposition of said substrate. - View Dependent Claims (25, 26, 27)
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28. A method of etching a portion of a substrate, comprising the steps of:
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irradiating said substrate with a first light pulse of sufficient photon energy to cause surface molecules of said substrate to be converted to a singlet state, said photon energy of said first light source being further sufficient to photochemically ablate at least some of said molecules raised to said singlet state; and irradiating said substrate with a second light pulse having sufficient photon energy to cause a portion of said molecules not photochemically ablated by said first light source to absorb sufficient energy to photochemically ablate.
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29. An apparatus for enhancing ablation of a portion of a substrate comprising:
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a first radiation source for generating radiation of a first wavelength; a second radiation source for generating radiation of a second longer wavelength; means for directing radiation from said first and second radiation sources to substantially the same area of said substrate; means associated with said first and second radiation sources for controlling the time separation between generation of radiation by said first and second radiation sources. - View Dependent Claims (30)
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Specification