Navigation and Sample Processing Using an Ion Source Containing both Low-Mass and High-Mass Species
AssigneeFEI Company
InventorChad Rue
Life of this patent
Estimating the term…
Abstract
An improved method and apparatus for imaging and milling a substrate using a FIB system. Preferred embodiments of the present invention use a mixture of light and heavy ions, focused to the same focal point by the same beam optics, to simultaneously mill the sample surface (primarily with the heavy ions) while the light ions penetrate deeper into the sample to allow the generation of images of subsurface features. Among other uses, preferred embodiments of the present invention provide improved methods of navigation and sample processing that can be used for various circuit edit applications, such as backside circuit edit.
Claims39
An apparatus for high accuracy beam placement and navigation to a feature of interest on a sample, comprising:
- a source of ions, the source producing ions of more than one elemental species;
- and
- a particle beam column for producing a coaxial mixed beam of ions including ions of more than one elemental species and for focusing the mixed beam to a focal point at or near the sample.
(canceled)
(canceled)
(canceled)
(canceled)
(canceled)
An apparatus for accurately locating a feature of interest on a sample, comprising:
- a particle beam column for producing a beam of charged particles along a beam axis to image and/or mill the sample;
- a source of charged particles from which the particle beam is composed, wherein the source of particles produces at least a first and a second species of ions, said first and second species having different elemental compositions and different atomic mass;
- a mass filter for filtering between the at least first and second species of ions so that the charged particle beam comprises only ions of one of the first and second species of ions, and
- a computer-readable memory storing computer instructions, the instructions including a program for controlling the apparatus for causing rapid switching back and forth between the at least first and second species of ions at a selected frequency.
A method for processing a sample having subsurface features, the method comprising:
- providing particle beam system including an ion source that produces at least two species of ions and an ion beam column for producing a beam of ions, the beam including the at least two species of ions, and the at least two species of ions having different elemental compositions and comprising a lighter ion species having a lower atomic mass and a heavier ion species having a higher atomic mass;
- directing the ion beam toward the sample to image and process the sample;
- detecting secondary electrons resulting from the impact of ions of the lighter ion species on the sample to form an image of a subsurface feature of the sample;
- using the location of the imaged subsurface feature to direct the ion beam toward the sample;
- and
- processing the sample using the ions of the heavier ion species to mill the sample surface.
Dependencies are inferred from the claim text.