Electron beam inspection system and method

An automatic system for the automatic inspection of a substantially non-conductive substrate comprising:

• a charged particle beam column to deliver and scan a charged particle beam on a surface of said substrate;
• a charged particle detector to detect at least one of the three types of charged particles emanating from the top and bottom surfaces of said substrate, namely, secondary charged particles, back-scattered charged particles and transmitted charged particles;
• an alignment system to align said substrate beneath said charged particle beam;
• and
• a multi-processor image defect computer coupled to said charged particle detector to identify defects on said substrate.

A method for the automatic inspection of a substantially non-conductive substrate using an electron beam from a field emission source, said method comprising the steps of:

• a. positioning the electron beam on the substrate accurately by measuring the position of the substrate;
• b. deflecting the electron beam to the desired position of said substrate measured in step a.;
• c. scanning the desired position of a surface of the substrate with the electron beam as said substrate is continuously moving with at least one degree of motion in an x-y plane;
• and
• d. detecting at least one of the three types of charged particles emanating from the top and bottom surfaces of said substrate as a result of step c., namely, secondary charged particles, back-scattered charged particles and transmitted charged particles;
• and
• e. identifying defects on said substrate with a multi-processor image defect computer using information from step d.;
• wherein step a. includes computing misalignment of an image produced by step d. to control the positioning of said electron beam.

An automatic system for the automatic inspection of a substantially non-conductive substrate comprising:

• a field emission electron source to provide an electron beam;
• a charged particle beam column to deliver and scan said electron beam from said field emission electron source on a surface of said substrate;
• a charged particle detector to detect at least one of the three types of charged particles emanating from the top and bottom surfaces of said substrate, namely, secondary charged particles, back-scattered charged particles and transmitted charged particles;
• an interferometer to determine the position of said substrate with respect to said electron beam;
• a stage disposed to receive said substrate and to provide continuous motion relative to said electron beam;
• and
• a multi-processor image defect computer coupled to said at least one charged particle detector to identify defects on said substrate.

An automatic system for the automatic inspection of a substantially non-conductive substrate using an electron beam, said system comprising:

• a field emission source to provide an electron beam;
• means for positioning the electron beam on the substrate accurately by measuring the position of the substrate;
• means for deflecting the electron beam to the desired position of said substrate as measured by said positioning means;
• means for scanning the desired position of a surface of the substrate with the electron beam;
• a charged particle detector to detect at least one of the three types of charged particles emanating from the top and bottom surfaces of said substrate, namely, secondary charged particles, back-scattered charged particles and transmitted charged particles;
• a continuously moving x-y stage disposed to receive said substrate and to provide at least one degree of motion to said substrate while the substrate is being scanned by the electron beam;
• and
• a multi-processor image defect computer responsive to said charged particle detector to identify defects on said substrate;
• wherein said positioning means includes an alignment computer coupled to said charged particle detector and said x-y stage to determine misalignment of an image produced by said charged particle detector and said x-y stage, and to control the movement of said x-y stage.

An electrostatic immersion objective lens for use within a charged particle beam column wherein said column delivers an electron beam from an electron source to a surface of a specimen through said electrostatic immersion objective lens that is spaced apart from said specimen, said electrostatic immersion objective lens comprising:

• a first, a second, and a third electrode, said objective lens disposed to be positioned with said first electrode furthest from said specimen, said third electrode closest to said specimen, and said second electrode intermediate said first and third electrodes;
• a first potential adjustment circuit connected between said first and third electrodes with said third electrode at a more negative potential that said first electrode;
• and
• a second potential adjustment circuit connected between said second electrode and one of said first and third electrodes to adjust the potential to create a substantially field free region at said surface of said specimen.

A method for scanning an electron beam on the surface of a continuously moving specimen, said method to improve the image contrast, reduce image noise and minimize heating of said specimen, said method comprising the steps of:

• a. scanning said electron beam on said specimen in a direction that is substantially perpendicular to the direction of instantaneous motion of said specimen;
• b. deflecting said electron beam in the direction of the instantaneous motion of said specimen to scan the same area of said specimen several times;
• c. detecting at least one of the three types of charged particles emanating from the top and bottom surfaces of said substrate as a result of step c., namely, secondary charged particles, back-scattered charged particles and transmitted charged particles;
• d. identifying defects on said substrate using information from step c.;
• and
• e. repeating steps a. and b. as many times as desired.