METHOD AND APPARATUS FOR PROCESSING THIN METAL LAYERS
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Abstract
A method and apparatus for processing a thin metal layer on a substrate to control the grain size, grain shape, and grain boundary location and orientation in the metal layer by irradiating the metal layer with a first excimer laser pulse having an intensity pattern defined by a mask to have shadow regions and beamlets. Each region of the metal layer overlapped by a beamlet is melted throughout its entire thickness, and each region of the metal layer overlapped by a shadow region remains at least partially unmelted. Each at least partially unmelted region adjoins adjacent melted regions. After irradiation by the first excimer laser pulse, the melted regions of the metal layer are permitted to resolidify. During resolidification, the at least partially unmelted regions seed growth of grains in adjoining melted regions to produce larger grains. After completion of resolidification of the melted regions following irradiation by the first excimer laser pulse, the metal layer is irradiated by a second excimer laser pulse having a shifted intensity pattern so that the shadow regions overlap regions of the metal layer having fewer and larger grains. Each region of the metal layer overlapped by one of the shifted beamlets is melted throughout its entire thickness, while each region of the metal layer overlapped by one of the shifted shadow regions remains at least partially unmelted. During resolidification of the melted regions after irradiation by the second radiation beam pulse, the larger grains in the at least partially unmelted regions seed growth of even larger grains in adjoining melted regions. The irradiation, resolidification and re-irradiation of the metal layer may be repeated, as needed, until a desired grain structure is obtained in the metal layer.
111 Citations
88 Claims
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1-67. -67. (canceled)
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68. An apparatus for processing a thin metal layer disposed on a substrate comprising:
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(a) a pulsed radiation beam source for providing radiation beam pulses; (b) a beam mask through which the radiation beam pulses pass for defining a respective intensity pattern of each one of the radiation beam pulses for irradiating at least a portion of the metal layer, the intensity pattern having at least one shadow region and at least one beamlet, wherein during irradiation by a radiation beam pulse, each region of the at least a portion of the metal layer overlapped by a respective one of the at least one beamlet is melted throughout its entire thickness, and each region of the at least a portion of the metal layer overlapped by a respective one of the at least one shadow region remains at least partially unmelted; (c) a sample translation stage for holding the metal layer on the substrate while the at least a portion of the metal layer is being irradiated by the radiation beam pulses, and for translating the metal layer on the substrate in a lateral direction with respect to the radiation beam pulses; and wherein the sample translation stage microtranslates the substrate having the metal layer in a lateral direction with respect to the radiation beam pulses so as to shift the intensity pattern of the radiation beam pulses with respect to the metal layer from one radiation beam pulse to another. - View Dependent Claims (70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88)
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69. (canceled)
Specification