Model 6487 Reference Manual
Applications Guide
G-25
Connections are made to the Model 6487 through the triax input connector (located on the
rear panel) (
) as well as the voltage source output terminals to provide the nec-
essary bias voltage.
Figure G-22
Basic connection scheme
klqb
The details on
“Typical range change transients,” page G-12
may be particu-
larly relevant to this application
Focused ion beam applications
Focused Ion Beam (FIB) systems have been developed to perform nanometer-scale imag-
ing, micro machining, and mapping in the semiconductor industry. Typical applications
include mask repair, circuit modification, defect analysis, and sample preparation of site-
specific locations on integrated circuits.
FIB systems use a finely focused ion beam for imaging or for site specific sputtering or
milling. The magnitude of the beam current determines what type of operation is per-
formed. A low beam current results in very little material being sputtered and is, therefore,
ideal for imaging applications. Utilization of high beam currents resulting in a great deal
of material being removed by sputtering, and is subsequently well suited for precision
milling operations.
Therefore, whether the application calls for imaging or a complete circuit modification,
monitoring and control of the beam current is critical to the success of the process. The ion
beam current cannot be measured directly, but requires the use of an ion detector. There
are several detectors commonly used throughout the industry including Channeltron
®
,
Daly, Microchannel plate, and the Faraday cup. The Faraday cup can only be used in an
analog mode and is, therefore, not as sensitive as newer current pulse devices.
Calibrated Light Source
Wafer
Probe Needles
Model 6487
Pads
Probe Needles
Photodiode
Bias Voltage
