Scanning system for inspecting anamolies on surfaces

A method for detecting anomalies on a surface;

• comprising:
• directing a focused beam of radiation towards said surface to illuminate an area of the surface defining a spot having a spot size whose minimum width is in the range of about 5 to 15 microns;
• causing relative motion between the beam and the surface by an acousto-optic deflector so that the beam scans a path covering substantially the entire surface;
• and
• collecting radiation scattered along said path at one or more detectors positioned away from any specular reflection direction of the beam from the surface for detecting anomalies;
• wherein the spot size and said directing and causing are such that the surface is inspected at a speed not less than about 1.5 cm2/s.

A method for detecting anomalies on a surface;

• comprising:
• directing a beam of radiation towards said surface to illuminate an area of the surface defining a spot having a spot size whose minimum width is in the range of about 5 to 15 microns;
• causing relative motion between the beam and the surface by an acousto-optic deflector so that the beam scans a path covering substantially the entire surface;
• and
• collecting radiation scattered along said path at one or more detectors positioned away from any specular reflection direction of the beam from the surface for detecting anomalies;
• said surface having dimensions of not less than 200 mm in any direction along the surface, wherein said directing and causing are such that the beam scans substantially the entire surface in about 50 to 90 seconds.

A system for detecting anomalies on a surface of a semiconductor wafer;

• comprising:
• optics directing a focused beam of radiation towards said surface to illuminate an area of the surface defining a spot having a spot size whose minimum width is in the range of about 5 to 15 microns;
• an acousto-optic deflector that deflects the focused beam so that the beam scans across the surface;
• a moving stage causing relative motion between the beam and the wafer so that the beam scans a path covering substantially the entire surface;
• and
• one or more detectors positioned away from any specular reflection direction of the beam from the surface collecting radiation scattered along said path for detecting anomalies;
• wherein the spot size, said optics, said deflector and stage are such that the beam substantially inspects the entire surface of the wafer at a throughput in excess of about 40 wafers per hour for 150 mm diameter wafers, at a throughput in excess of about 20 wafers per hour for 200 mm diameter wafers, or at a throughput in excess of about 10 wafers per hour for 300 mm diameter wafers.

A system for detecting anomalies on a surface;

• comprising:
• optics directing a focused beam of radiation towards said surface to illuminate an area of the surface defining a spot having a spot size whose minimum width is in the range of about 5 to 15 microns;
• an acousto-optic deflector that deflects the focused beam so that the beam scans across the surface;
• a moving stage causing relative motion between the beam and the surface so that the beam scans a path covering substantially the entire surface;
• and
• one or more detectors positioned away from any specular reflection direction of the beam from the surface collecting radiation scattered along said path for detecting anomalies;
• wherein the spot size, said optics, said deflector and stage are such that the surface is inspected at a speed not less than about 1.5 cm2/s.

A system for detecting anomalies on a surface;

• comprising:
• optics directing a beam of radiation towards said surface to illuminate an area of the surface defining a spot having a spot size whose minimum width is in the range of about 5 to 15 microns;
• an acousto-optic deflector that deflects the focused beam so that the beam scans across the surface;
• a moving stage causing relative motion between the beam and the surface so that the beam scans a path covering substantially the entire surface;
• and
• one or more detectors positioned away from any specular reflection direction of the beam from the surface collecting radiation scattered along said path for detecting anomalies;
• said surface having dimensions of not less than 200 mm in any direction along the surface, wherein the spot size and said optics and stage are such that the beam scans substantially the entire surface in about 50 to 90 seconds.

A method for detecting anomalies on a surface of a semiconductor wafer;

• comprising:
• directing a focused beam of radiation towards said surface to illuminate an area of the surface defining a spot having a spot size;
• causing relative motion between the beam and the wafer by an acousto-optic deflector so that the beam scans a path covering substantially the entire surface;
• and
• collecting radiation scattered along said path at one or more detectors positioned away from any specular reflection direction of the beam from the surface for detecting anomalies;
• wherein the spot size and said directing and causing are such that the beam substantially inspects the entire surface of the wafer at a throughput in excess of about 40 wafers per hour for 150 mm diameter wafers, at a throughput in excess of about 20 wafers per hour for 200 mm diameter wafers, or at a throughput in excess of about 10 wafers per hour for 300 mm diameter wafers.

A method for detecting anomalies on a surface;

• comprising:
• directing a focused beam of radiation towards said surface to illuminate an area of the surface defining a spot having a spot size;
• causing relative motion between the beam and the surface by an acousto-optic deflector so that the beam scans a path covering substantially the entire surface;
• and
• collecting radiation scattered along said path at one or more detectors positioned away from any specular reflection direction of the beam from the surface for detecting anomalies;
• wherein the spot size and said directing and causing are such that the surface is inspected at a speed not less than about 1.5 cm2/s.

A method for detecting anomalies on a surface;

• comprising:
• directing a beam of radiation towards said surface to illuminate an area of the surface defining a spot having a spot size;
• causing relative motion between the beam and the surface by an acousto-optic deflector so that the beam scans a path covering substantially the entire surface;
• and
• collecting radiation scattered along said path at one or more detectors positioned away from any specular reflection direction of the beam from the surface for detecting anomalies;
• said surface having dimensions of not less than 200 mm in any direction along the surface, wherein said spot size and said directing and causing are such that the beam scans substantially the entire surface in about 50 to 90 seconds.

A system for detecting anomalies on a surface of a semiconductor wafer;

• comprising:
• optics directing a focused beam of radiation towards said surface to illuminate an area of the surface defining a spot having a spot size;
• an acousto-optic deflector that deflects the focused beam so that the beam scans across the surface;
• a moving stage causing relative motion between the beam and the wafer so that the beam scans a path covering substantially the entire surface;
• and
• one or more detectors positioned away from any specular reflection direction of the beam from the surface collecting radiation scattered along said path for detecting anomalies;
• wherein the spot size, said optics, said deflector and stage are such that the beam substantially inspects the entire surface of the wafer at a throughput in excess of about 40 wafers per hour for 150 mm diameter wafers, at a throughput in excess of about 20 wafers per hour for 200 mm diameter wafers, or at a throughput in excess of about 10 wafers per hour for 300 mm diameter wafers.

A system for detecting anomalies on a surface;

• comprising:
• optics directing a focused beam of radiation towards said surface to illuminate an area of the surface defining a spot having a spot size;
• an acousto-optic deflector that deflects the focused beam so that the beam scans across the surface;
• a moving stage causing relative motion between the beam and the surface so that the beam scans a path covering substantially the entire surface;
• and
• one or more detectors positioned away from any specular reflection direction of the beam from the surface collecting radiation scattered along said path for detecting anomalies;
• wherein the spot size, said optics, said deflector and stage are such that the surface is inspected at a speed not less than about 1.5 cm2/s.

A system for detecting anomalies on a surface;

• comprising:
• optics directing a beam of radiation towards said surface to illuminate an area of the surface defining a spot having a spot size;
• an acousto-optic deflector that deflects the focused beam so that the beam scans across the surface;
• a moving stage causing relative motion between the beam and the surface so that the beam scans a path covering substantially the entire surface;
• and
• one or more detectors positioned away from any specular reflection direction of the beam from the surface collecting radiation scattered along said path for detecting anomalies;
• said surface having dimensions of not less than 200 mm in any direction along the surface, wherein the spot size, said optics, said deflector and stage are such that the beam scans substantially the entire surface in about 50 to 90 seconds.

A method for detecting anomalies on a surface;

• comprising:
• directing a focused beam of radiation at a grazing angle towards said surface;
• causing relative motion between the beam and the surface by a device comprising an acousto-optic deflector so that the beam scans a scan path covering substantially the entire surface, said path including a plurality of scan path segments, wherein each of at least some of such scan path segments has a span shorter than the dimensions of the surface;
• and
• collecting radiation scattered along said path;
• and
• processing information in the collected radiation to detect anomalies.

A system for detecting anomalies on a surface;

• comprising:
• optics directing a focused beam of radiation at a grazing angle towards said surface;
• a moving stage causing relative motion between the beam and the surface so that the beam scans a scan path covering substantially the entire surface, said optics comprising an acousto-optic deflector that scans the beam across the surface so that said path comprises a plurality of scan path segments, wherein each of at least some of such scan path segments has a span shorter than the dimensions of the surface;
• and
• one or more detectors collecting radiation scattered along said path;
• and a processor processing information in the collected radiation from the one or more detectors to detect anomalies.