US 11,605,525 B2 · System and method of preparing integrated circuits for backside probing using charged particle beams

Abstract

Described herein are a system and method of preparing integrated circuits (ICs) so that the ICs remain electrically active and can have their active circuitry probed for diagnostic and characterization purposes using charged particle beams. The system employs an infrared camera capable of looking through the silicon substrate of the ICs to image electrical circuits therein, a focused ion beam system that can both image the IC and selectively remove substrate material from the IC, a scanning electron microscope that can both image structures on the IC and measure voltage contrast signals from active circuits on the IC, and a means of extracting heat generated by the active IC. The method uses the system to identify the region of the IC to be probed, and to selectively remove all substrate material over the region to be probed using ion bombardment, and further identifies endpoint detection means of milling to the required depth so as to observe electrical states and waveforms on the active IC.

Claims17

Dependent claims

A method comprising:

removing bulk material from a backside of a sample, a front side of the sample including an active layer, wherein removal of the bulk material leaves a thin layer of the bulk material covering the active layer on the backside;
locating corner fiducials on a front side of the sample using an infrared imaging system;
locating a probe area based on coordinates provided by a debug control;
locating a region outside of the probe area;
milling an alignment fiducial on the backside of the sample in the region outside of the probe area;
imaging the probe area and the alignment fiducial using the infrared system;
determining an offset between the alignment fiducial and the probe area based on the imaging;
and
locating the probe location based on the offset;
milling, by an ion beam, the thin layer to expose the probe area of the active layer;
monitoring the milling of the thin layer based on a signature of the probe location indicating that the active layer has been reached;
and
terminating, in response to the monitoring, the milling.

10 more elements

A system comprising:

an electron beam column to provide an electron beam;
an ion beam column to provide an ion beam;
one or more detectors;
and
a controller coupled to the electron and ion beam columns, the controller configured to:
locate corner fiducials on a front side of the sample using an infrared imaging system;
locate a probe area based on coordinates provided by a debug control;
locate a region outside of the probe area;
mill an alignment fiducial on the backside of the sample in the region outside of the probe area;
image the probe area and the alignment fiducial using the infrared system;
determine an offset between the alignment fiducial and the probe area based on the imaging;
and
locate the probe location based on the offset
mill, by the ion beam, a thin layer to expose the probe area of the active layer;
monitor the milling of the thin layer based on a signature of the probe location indicating that the active layer has been reached;
and
terminate, in response to the monitoring, the milling.

14 more elements

Dependencies are inferred from the claim text.

System and method of preparing integrated circuits for backside probing using charged particle beams

Life of this patent

System and method of preparing integrated circuits for backside probing using charged particle beams

Life of this patent

Abstract

Claims17