Enhancement of X-ray reflectometry by measurement of diffuse reflections

Apparatus for inspection of a sample having a surface layer, the apparatus comprising:

• a radiation source, which is adapted to direct a collimated beam of X-rays toward a surface of the sample in a first configuration of the apparatus, and to direct a converging beam of the X-rays toward the surface of the sample in a second configuration of the apparatus;
• a detector assembly, which is arranged to sense the X-rays reflected from the surface so as to generate first and second reflectance spectra as a function of elevation angle relative to the surface in the first and second configurations, respectively;
• and
• a signal processor, which is coupled to receive and process the first reflectance spectrum so as to measure a diffuse reflection property of the sample, and to analyze the second reflectance spectrum using the diffuse reflection property so as to determine a characteristic of the surface layer of the sample.

A cluster tool for producing microelectronic devices, comprising:

• a deposition station, which is adapted to deposit a thin-film layer on a surface of a semiconductor wafer;
• and
• an inspection station, comprising:
• a radiation source, which is adapted to direct a collimated beam of X-rays toward the surface of the wafer in a first configuration of the inspection station, and to direct a converging beam of the X-rays toward the surface of the wafer in a second configuration of the inspection station;
• a detector assembly, which is arranged to sense the X-rays reflected from the surface so as to generate first and second reflectance spectra as a function of elevation angle relative to the surface in the first and second configurations, respectively;
• and
• a signal processor, which is coupled to receive and process the first reflectance spectrum so as to measure a diffuse reflection property of the surface, and to analyze the second reflectance spectrum using the diffuse reflection property so as to determine a characteristic of the thin-film layer.

Apparatus for producing microelectronic devices, comprising:

• a production chamber, which is adapted to receive a semiconductor wafer;
• a deposition device, which is adapted to deposit a thin-film layer on a surface of the semiconductor wafer within the chamber;
• a radiation source, which is adapted to direct a collimated beam of X-rays toward the surface of the wafer in the production chamber in a first configuration of the source, and to direct a converging beam of the X-rays toward the surface of the wafer in the production chamber in a second configuration of the source;
• a detector assembly, which is arranged to sense the X-rays reflected from the surface of the wafer in the production chamber so as to generate first and second reflectance spectra as a function of elevation angle relative to the surface in the first and second configurations, respectively;
• and
• a signal processor, which is coupled to receive and process the first reflectance spectrum so as to measure a diffuse reflection property of the surface, and to analyze the second reflectance spectrum using the diffuse reflection property so as to determine a characteristic of the thin-film layer.