Ion beam mill etch depth monitoring with nanometer-scale resolution
AssigneeThe Regents of the University of California
InventorsShane A. Cybart, Robert C. Dynes
Life of this patent
Estimating the term…
Abstract
A method for measuring conductance of a material real-time during etching/milling includes providing a fixture having a socket for receiving the material. The socket is attached to a printed circuit board (PCB) mounted on one side of a plate that has at least one opening for providing ion beam access to the material sample. Conductive probes extend from the other side of the PCB to contact and span a target area of the material. A measurement circuit in electrical communication with the probes measures the voltage produced when a current is applied across the material sample to measure changes in electrical properties of the sample over time.
Claims16
A fixture for measuring conductance of a material real-time during etching/milling of the material, comprising:
- a thermally-conductive base;
- a socket attached to the base, the socket having at least one recess formed therein for receiving a material sample;
- a printed circuit board (PCB) having a first side, a second side, and at least one PCB opening therethrough;
- a plate attached to the first side of the PCB, the plate having at least one plate opening therethrough aligned with the at least one PCB opening for providing etch/milling beam access to the material sample, the plate and PCB configured to be releasably attached to the socket;
- a plurality of conductive probes extending from the second side of the PCB, the probes configured to removably contact and span a target area of the material to be etched, and wherein the PCB has circuitry formed thereon in electrical communication with the probes, and wherein the at least one PCB opening and the at least one plate opening are each configured to expose a target area of the material to the etch/milling beam while masking the probes from the etch/milling beam and from re-deposition of removed material;
- and a measurement circuit in electrical communication with the probes, wherein a current applied across a first pair of the probes produces a voltage across the material sample to a second pair of the probes to measure changes in electrical properties of the sample over time.
A method for monitoring removal of a material during etch/milling comprising:
- enclosing a material sample within a fixture so that the material sample is contacted by a four point probe having two current probes electrically connected to a sinusoidal current source and two voltage probes electrically connected to a voltage detection circuit, the fixture comprising a masking structure having at least one opening formed therein, the at least one opening configured to expose a target area of the material sample to an etch/milling beam while masking the probes from the etch/milling beam and from re-deposition of removed material;
- measuring changes in conductance of the material sample with time as the etch/milling beam is directed onto the target area through the at least one opening.
Dependencies are inferred from the claim text.