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Fast sample height, AOI and POI alignment in mapping ellipsometer or the like

  • US 8,436,994 B2
  • Filed: 01/15/2011
  • Issued: 05/07/2013
  • Est. Priority Date: 03/21/2000
  • Status: Expired due to Term
First Claim
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1. A sample alignment system (AS) in functional combination within a sample investigation system (ES) selected from the group consisting of:

  • ellipsometer;

    polarimeter;

    reflectometer;

    spectrophotometer; and

    Mueller Matrix measuring system;

    said sample investigation system (ES) comprising;

    a source (ELS) of a sample (SAM) investigation beam of electromagnetic radiation;

    a stage (STG) for supporting a sample (SAM);

    a data detector (DDET); and

    means for adjusting the relative “

    height”

    positioning between said stage (STG) for supporting a sample (SAM) and, as a unit, said source (ELS) of a sample investigation beam of electromagnetic radiation and data detector (DDET);

    as well as means for translating relative positioning of said sample (SAM) with respect to said source (ELS) of a sample investigation beam of electromagnetic radiation and said data detector (DDET), along two orthogonal axes, and means for adjusting the relative orientation of the sample investigation system (ES) with respect to said sample (SAM) to set the angle and plane of incidence of said sample (SAM) investigation beam of electromagnetic radiation with respect to a surface of said sample (SAM);

    said sample investigation system (ES) optionally comprising at least one polarizer (P), analyzer (A), compensator (RC) and/or focusing means (CL1) (CL2) (CL3) (CL4) between said source (ELS) of a sample (SAM) investigation beam of electromagnetic radiation and said data detector (DDET);

    such that in use a sample investigation beam of electromagnetic radiation from said source (ELS) thereof approaches said sample (SAM) at an oblique angle-of-incidence and reflects therefrom into said data detector (DDET); and

    wherein said alignment system (AS) comprises;

    an alignment source (ALS) of an alignment beam of electromagnetic radiation;

    a first alignment beam focusing means (CLA1) for focusing an alignment beam of electromagnetic radiation provided from said source (ALS) thereof onto a sample (SAM) on said sample investigation system (ES) stage (STG) for supporting a sample (SAM);

    a second alignment focusing means (CLA2) for focusing alignment beam electromagnetic radiation which reflects from said sample onto a two dimensional detector array (SCRN1); and

    said two dimensional detector array (SCRN1);

    said sample alignment system (AS) further comprising;

    between said second alignment focusing means (CLA2) and said two dimensional detector array (SCRN1), a beam splitter (BS) which diverts a portion of the alignment beam electromagnetic radiation which reflects from said sample (SAM) to a secondary two dimensional detector array (SCRN2), and said secondary two dimensional detector array (SCRN2);

    such that in use an alignment beam of electromagnetic radiation from said source (ALS) thereof is focused onto said sample (SAM) at an oblique angle-of-incidence and reflects therefrom and is focused onto said two dimensional detector array (SCRN1) with a portion thereof being directed to secondary two dimensional detector array (SCRN2) via beam splitter (BS);

    said sample (SAM) investigation system (ES) and alignment system (AS) being mounted with respect to one another such that the sample investigation beam of electromagnetic radiation and said alignment beam of electromagnetic radiation impinge on said sample (SAM) at substantially the same location;

    such that in use, while monitoring two dimensional detector array (SCRN1), causing an alignment beam of electromagnetic radiation from said source (ALS) thereof to be focused onto said sample (SAM) at an oblique angle-of-incidence, reflect therefrom and become focused onto said two dimensional detector array (SCRN1), adjusting the means for adjusting the relative “

    height”

    positioning between said stage (STG) for supporting a sample until the location at which the alignment beam arrives thereat is at an aligned position thereupon;

    andsuch that in use the means for adjusting the relative orientation of the sample investigation system (ES) with respect to said sample (SAM), to set the angle and plane of incidence of said beam with respect to a surface of said sample (SAM) until said alignment beam reflected from said sample (SAM) surface appears on the two dimensional detector array (SCRN2) an aligned position thereupon.

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