Chapter/Index: Introduction | A |
B |
C |
D |
E |
F |
G |
H |
I |
J |
K |
L |
M |
N |
O |
P |
Q |
R |
S |
T |
U |
V |
W |
X |
Y |
Z |
Appendix
Electron Beam Testing (EBT)
| Electron Beam Testing (EBT) involves using an electron beam, typically from a Scanning Electron Microscope (SEM), to evaluate the electrical properties of integrated circuits or devices. It is particularly useful for testing semiconductor devices like VLSIs, where increasing speed and density require precise testing and failure analysis. EBT uses the interactions between the electron beam and the device, such as secondary electron emission and current absorption, to probe internal voltages and diagnose faults.
There are two main approaches to localize defects in a device:
- Voltage detection with a shifting probe: Signals are fed into the input terminals, and the internal voltages are probed, allowing localization of defect points based on electrical properties. It applies electrical test signals or stimuli to the designated input points (or terminals) of a semiconductor device or integrated circuit (IC). These input terminals are specific locations where the device receives its electrical signals for operation, such as clock pulses, control signals, or data inputs. By feeding signals into these input terminals, the device is activated or set to perform certain functions. The purpose is to simulate its normal operation, so that the electron beam can then probe various points within the circuit. This allows engineers to observe how the internal voltages of the device change in response to the applied signals, thereby identifying potential faults or defects within the circuit. The feeding signals into the input terminals is analogous to turning on the device and running it through its regular tasks, but with specialized inputs designed for testing and diagnostics rather than everyday use.
- Response comparison: Signals are sequentially fed via a movable current feeder, and the output response is compared with expected results to locate defects.
EBT offers several advantages over traditional methods, including:
- Higher spatial and temporal resolution.
- Visualization of two-dimensional voltage distributions.
EBT methods, such as stroboscopic imaging, enable real-time voltage and waveform measurements, allowing for detailed failure analysis. However, it requires careful control of the electron beam to prevent adverse effects, such as device charging or contamination
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