Emission Microscopy (EMMI) Analysis

Scope

Emission microscopy covers the detection and localization of photon-emitting defects in semiconductor devices, integrated circuits, and related electronic components. The technique detects light emission from sites of abnormal electrical activity while the device is electrically biased, and maps that emission to a physical location on the device.

Key aspects of the technique include:

• Photon emission detection – captures faint light emitted from active failure sites using highly sensitive detectors (such as cooled CCD, InGaAs, or photomultiplier-based systems) operating from the visible into the near-infrared range
• Front-side and backside analysis – emission can be detected from the front (circuit) side or, increasingly for flip-chip and multilayer devices, from the backside through the silicon using near-infrared-sensitive detectors
• Biased-device operation – the device is electrically biased into the failing condition during analysis so that the defect actively emits; static and dynamic bias conditions can be applied depending on the failure
• Defect types detected – junction leakage, gate oxide breakdown, latch-up, ESD damage, hot-carrier effects, dielectric defects, and other sites of abnormal current flow
• Image overlay – the captured emission is superimposed on a reference optical image of the device to precisely identify the location of the emission site
• Complementary techniques – frequently combined with thermal emission (lock-in thermography), OBIRCH, and laser stimulation methods for comprehensive fault isolation

Applications

• Semiconductor device fault isolation – locating leakage, short, and breakdown sites in transistors, diodes, and IC structures as the first step before physical failure analysis
• Integrated circuit failure analysis – pinpointing defects in complex ICs where the failing area must be located among millions of features before deprocessing
• Gate oxide and dielectric defect localization – detecting emission from gate oxide breakdown and dielectric defects that cause leakage or device failure
• ESD and EOS damage localization – finding the physical site of electrostatic discharge or electrical overstress damage within a device
• Latch-up investigation – locating latch-up sites in CMOS devices where parasitic structures cause abnormal current flow
• Product and reliability failure analysis – investigating devices that failed during qualification, burn-in, or field use to localize the defect and support root cause determination
• Process and yield improvement – identifying recurring defect locations across failing devices to feed back into process and design improvements

Benefits

• Non-destructive fault localization – emission microscopy locates the defect without altering or damaging the device, preserving it for subsequent physical analysis at the identified site
• Dramatically narrows the analysis area – by pinpointing the emission site, the technique reduces the area that costly and time-consuming physical deprocessing must examine, from the whole die down to a specific feature
• Detects a wide range of defect types – because many different failure mechanisms produce photon emission, EMMI is broadly applicable across leakage, breakdown, ESD, and dielectric failures
• Backside capability for modern packages – near-infrared detection through the silicon enables analysis of flip-chip and multilayer devices where the front side is inaccessible
• Complements other fault-isolation methods – used together with thermal and laser techniques, emission microscopy contributes to a comprehensive fault-isolation workflow that maximizes the chance of locating elusive defects