The working principle and application range of low light microscope EMMI/OBIRCH
The beam induced resistance change (OBIRCH) function is commonly integrated with a low light microscope (EMMI) in a detection system, collectively known as PEM (Photo Emission Microscope). The two complement each other and can effectively cope with the vast majority of failure modes.
EMMI
Emission Microscope (EMMI) (wavelength range: 400nm to 1100nm) is a tool used to detect and locate fault points, and to search for bright and hot spots. By detecting photons excited by electron hole binding and thermal carriers. In IC components, EHP (Electron Hole Pairs) Recognition emits photons. For example, when a bias voltage is applied to a pn junction, the electrons of n are easily diffused to p, and the holes of p are also easily diffused to n, and then EHP Recombination is performed with the holes at the p end (or electrons at the n end).
Application:
The leakage caused by detecting various component defects, such as gate oxide defects, electrostatic discharge failure, latch up and leakage in circuit verification, junction leakage, forward bias, and transistors operating in the saturation region, can be located by EMMI, Detect bad spots or leakage areas in the array area of CMOS image sensing chips and LED flexible liquid crystal screens, and detect uneven lateral current distribution and leakage of LED type chip transistors.
Application:
1. Check the chip packaging wiring and the internal circuit of the chip for short circuit.
2. Short circuit and leakage of transistors and diodes.
3. Metal circuit defects and short circuits in TFT LCD panel&PCB/PCBA.
4. Some failed components on PCB/PCBA.
5. Dielectric layer leakage.
6. ESD blocking effect.
7. Depth estimation of failure points in 3D packaging (Stacked Die).
8. Positioning and detection of unopened failure points in chips (distinguishing packaging in Die)
9. The problem analysis of low impedance short circuits ("10ohm") is commonly used to analyze the testing of some unopened samples, as well as the failure location of metal circuits and components on large PCBs. The metal layer blocking OBIRCH and INGAAS cannot detect leakage, short circuits, and other situations will also be analyzed using it.
Detected highlights:
Defect that can produce bright spots - Junction Leakage; Contact hair
