Subsurface imaging using an electron beam
AssigneeFEI Company
InventorPeter Carleson
Life of this patent
Estimating the term…
Abstract
A method of navigating or endpointing a microscopic structure by subsurface imaging using a beam of electrons having sufficient energy to penetrate the surface and produce a subsurface image. For endpointing, when the subsurface image become relatively clear at a known electron energy, a user knows that he is approaching the buried feature. For navigating, a subsurface image can be formed of fiducials or other features to determine the position of the beam on the device.
Claims19
A method of processing a semiconductor device using ion beam milling and electron beam imaging, comprising:
- directing a focused ion beam toward a semiconductor device to mill a hole approaching a buried metal layer;
- directing toward the bottom of the hole an electron beam having sufficiently energetic electrons to obtain a subsurface image and collecting electrons ejected away from the hole to view the subsurface image of the metal layer through at least 0.1 μm of silicon;
- and
- using the image of the metal layer to determine when to stop milling with the focused ion beam.
A method of navigating a work piece, comprising:
- scanning on the work piece an electron beam having sufficiently high energy to produce an image of one or more subsurface features from secondary or backscattered electrons;
- and
- using the subsurface image to navigate on the work piece.
In a process of using a focused beam to cut a hole in a substrate to expose for imaging or alteration a subsurface, microscopic feature, the improvement comprising determining the location of the subsurface feature or determining when a beam is about the expose the subsurface feature by forming a subsurface image of the feature by directing toward the surface covering the subsurface feature an electron beam having a sufficiently high energy to produce an image of the subsurface, microscopic feature from secondary or backscattered electrons.
Dependencies are inferred from the claim text.