Three-dimensional imaging technique with occlusion avoidance

Claim 3

The method according to claim 1 wherein the first spanning step is carried out by imparting a relative motion between the substrate and a first pair of lines of light directed at the substrate from opposite sides to illuminate a separate one of a pair of spaced-apart strips of surface area and wherein the second spanning step is carried out by imparting a relative motion between the substrate and a second pair of lines of light directed at the substrate from opposite sides to illuminate a separate one of a pair of spaced-apart strips of surface area.

Claim 4

The method according to claim 2 wherein each of the first and second pairs of lines of light have linear profiles and wherein the three-dimensional image is established in accordance with a ratio of the difference in the intensities of electromagnetic radiation sensed when the substrate is spanned by the first and second pair of lines of light to the sum of the illumination intensities.

Claim 5

Apparatus for obtaining a three-dimensional image of a substrate with reduced incidence of occlusion of short features on the substrate by tall features comprising: first means for producing each of a first pair of lines of electromagnetic radiation directed at the substrate from opposite sides to irradiate a separate one of a pair of spaced-apart strips of area running across the substrate; second means producing each of a second pair of lines of electromagnetic radiation directed at the substrate from opposite sides, during intervals other than when the first pairs of lines of electromagnetic radiation are directed at the substrate, to irradiate a separate one of the pair of spaced-apart strips of area running across the substrate; means for sensing the intensity of electromagnetic radiation reflected from a strip of area contiguous to, and lying between, the strips separately irradiated by each of the first and second pairs of lines of electromagnetic radiation; means for imparting a relative motion between the substrate, the combination of the electromagnetic radiation-sensing means, and the first and second radiation-producing means so that the substrate is effectively spanned separately by each of the first and second pairs of lines of electromagnetic radiation while the electromagnetic radiation-sensing means senses the electromagnetic radiation reflected from each successive strip contiguous to, and lying between, the successive pairs of strips irradiated by the first and second lines of electromagnetic radiation; and means coupled to the electromagnetic radiation-sensing means for establishing a three-dimensional image of the substrate in accordance with a prescribed relationship between the electromagnetic radiation intensity sensed when the substrate is irradiated with the first pairs of lines of electromagnetic radiation and the radiation intensity when the substrate is irradiated with the second pairs of lines of electromagnetic radiation.

Claim 6

Apparatus for obtaining a three-dimensional image of a substrate with reduced incidence of occlusion of short features on the substrate by tall features comprising: first means for producing each of a first pair of lines of electromagnetic radiation directed at the substrate from opposite sides to irradiate a separate one of a pair of spaced-apart strips of area running across the substrate; second means producing each of a second pair of lines of electromagnetic radiation directed at the substrate from opposite sides, during intervals other than when the first pairs of lines of electromagnetic radiation are directed at the substrate, to irradiate a separate one of the pair of spaced-apart strips of area running across the substrate; means for sensing the intensity of electromagnetic radiation reflected from a strip of area contiguous to, and lying between, the strips separately irradiated by each of the first and second pairs of lines of electromagnetic radiation; means for imparting a relative motion between the substrate, the combination of the electromagnetic radiation-sensing means, and the first and second radiation-producing means so that the substrate is effectively spanned separately by each of the first and second pairs of lines of electromagnetic radiation while the electromagnetic radiation-sensing means senses the electromagnetic radiation reflected from each successive strip contiguous to, and lying between, the successive pairs of strips irradiated by the first and second lines of electromagnetic radiation; and means coupled to the electromagnetic radiation-sensing means for establishing a three-dimensional image of the substrate in accordance with a prescribed relationship between the electromagnetic radiation intensity sensed when the substrate is irradiated with the first pairs of lines of electromagnetic radiation and the radiation intensity when the substrate is irradiated with the second pairs of lines of electromagnetic radiation.

Claim 7

The apparatus according to claim 4 wherein the first means for irradiating the substrate with electromagnetic radiation comprises a first pair of light sources, each producing a beam of light directed at the substrate from opposite sides; and a pair of cylindrical lenses, each serving to refract the beam produced by a separate one of the first pair of light sources into a line of light.

Claim 8

The apparatus according to claim 5 wherein the second means for irradiating the substrate comprises a second pair of light sources, each producing a beam of light which is directed into a separate one of the cylindrical lenses to produce a separate one of a second pair of lines each directed at the substrate from opposite sides.

Claim 9

The apparatus according to claim 6 wherein the means of sensing electromagnetic radiation comprises a linescan camera.