Semiconductor devices can fail for many reasons: manufacturing defects, electrical overstress, electrostatic discharge, contamination, packaging problems, excessive temperature, mechanical stress, aging or defects introduced during assembly.
Finding the actual cause of an IC failure, however, is rarely as simple as looking at the damaged device.
Semiconductor failure analysis (FA) is the systematic process used to identify where a semiconductor device failed, determine the physical or electrical mechanism behind the failure and, ultimately, establish the root cause.
Failure analysis is important throughout the semiconductor lifecycle—from process development and qualification to high-volume manufacturing and failures discovered in customer applications. As semiconductor structures become smaller and more three-dimensional, locating defects is becoming increasingly challenging; NIST notes that device performance and reliability can depend on extremely small structural and material defects.
A typical failure-analysis investigation combines electrical failure analysis (EFA) with physical failure analysis (PFA). Electrical methods are generally used to characterize and localize the failing region, while physical techniques are then used to expose, image and characterize the defect responsible for the failure.
This guide explains the semiconductor failure-analysis process, the most commonly used techniques, typical IC failure mechanisms and how to choose the right failure-analysis laboratory.
Semiconductor failure analysis is the process of investigating a failed or abnormal semiconductor device to determine:
The purpose is therefore not simply to find visible damage. For example, a burned metal line might be easy to identify under a microscope, but the important question is why the metal line was damaged.
Was it caused by electrical overstress?
A design weakness?
A process defect?
Contamination?
A package-related problem?
Or did another failure occur first and subsequently create the visible damage?
A successful failure-analysis investigation attempts to distinguish the failure site, failure mechanism and root cause.
The physical location where the failure is detected.
The way the device behaves incorrectly, for example:
The physical or electrical process that created the failure, such as:
The underlying reason the failure occurred.
Determining the root cause is usually the most valuable result because it can enable corrective action in design, fabrication, assembly, testing or the end application.
Learn more: Common IC Failure Mechanisms and Their Causes
Failure analysis is used by semiconductor companies, fabless IC companies, foundries, OSATs, electronics manufacturers and system companies for several different purposes.
During development, FA can help engineering teams identify design weaknesses or process problems before a device reaches mass production.
If wafer sort or final test identifies repeating failures, physical analysis of failing devices can reveal systematic defects that may be reducing manufacturing yield.
Devices subjected to accelerated stress testing may subsequently be analyzed to understand the physical mechanism responsible for degradation or failure.
When a semiconductor device fails in the field, FA can help determine whether the cause originated in the IC, package, PCB assembly, operating environment or electrical system.
Failure analysis can expose fabrication-related problems involving contacts, vias, interconnects, dielectrics, interfaces, contamination and other structures.
The findings can support corrective and preventive action by connecting an observed failure with its underlying cause.
There is no single FA sequence suitable for every semiconductor device.
The exact workflow depends on the package, device architecture, failure mode and information already available.
However, many investigations follow a progression from non-destructive analysis toward increasingly invasive physical analysis.
A simplified workflow is:
1. Collect background information
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2. Confirm and reproduce the failure
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3. Perform electrical characterization
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4. Carry out non-destructive inspection
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5. Localize the electrical defect
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6. Decapsulate or expose the die if required
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7. Perform physical failure analysis
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8. Characterize materials and structures
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9. Determine the failure mechanism
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10. Identify the root cause and corrective action
Learn more: Semiconductor Failure Analysis Process: From Failure to Root Cause
A good failure-analysis investigation begins before the device enters the laboratory.
The analyst should understand as much as possible about the failed device and its operating history.
Useful information can include:
This information can significantly influence which FA techniques should be used first.
One important principle is to avoid destroying evidence too early. Destructive techniques such as cross-sectioning, FIB milling or certain forms of sample preparation can permanently alter the device.
For that reason, laboratories will often perform non-destructive examinations before progressing to destructive physical analysis.
Electrical Failure Analysis, commonly abbreviated EFA, attempts to characterize the electrical behavior of the failing device and localize the region responsible for the failure.
Typical electrical symptoms include:
Modern EFA is particularly important because the physical target for later analysis can be extremely small. Thermo Fisher describes the purpose of EFA as precisely characterizing and locating a defect so subsequent physical analysis can target the correct region and determine the root cause.
Depending on the device and failure type, EFA may involve techniques such as:
At advanced process nodes, nanoprobing can allow individual transistors or small circuit regions to be electrically evaluated inside an SEM. JEOL describes semiconductor nanoprobing as a technique used to evaluate devices, identify failing locations and determine failure causes through direct probing of circuitry.
Read the detailed guide: Electrical Failure Analysis (EFA) of Integrated Circuits
Whenever possible, the initial investigation should preserve the device.
Non-destructive techniques can help identify package defects, electrical abnormalities or suspicious regions before the IC is opened.
Common approaches can include:
External inspection can identify:
X-ray imaging can reveal internal package structures without physically opening the device.
It may be useful for examining:
Read more: X-Ray Inspection of Semiconductor Packages
Scanning Acoustic Microscopy (SAM) is frequently used for package-level inspection where internal interfaces must be examined.
Typical targets can include:
Read more: Scanning Acoustic Microscopy (SAM) for IC Package Analysis
One of the most difficult parts of semiconductor failure analysis is narrowing the problem from an entire IC containing potentially millions or billions of transistors to the particular location responsible for the failure.
This is called fault isolation or defect localization.
Possible techniques include:
NIST, for example, uses photon-emission microscopy techniques to study switching activity in integrated circuits.
The objective is normally to provide physical-analysis engineers with the smallest possible region of interest.
The more accurately the failure is localized, the less material must subsequently be removed or inspected.
If the failing semiconductor die is enclosed in a package, the package may need to be removed or opened before detailed die-level analysis can take place.
This process is known as decapsulation or decapping.
The objective is to expose the semiconductor die while preserving the failure evidence.
Depending on the package construction, different chemical, mechanical or other specialized methods may be used.
Decapsulation must be carefully controlled because an inappropriate process can:
Read more: IC Decapsulation: Methods, Process and Applications
Once the suspected failing region has been localized, Physical Failure Analysis (PFA) is used to examine the semiconductor structure directly.
PFA may investigate:
Cross-sectional analysis is frequently used to expose internal semiconductor structures. JEOL notes that cross-sectional analysis is commonly used for device failure analysis and that increasingly miniaturized devices require high spatial resolution.
Read more: Physical Failure Analysis (PFA) of Semiconductor Devices
No single analytical instrument can identify every semiconductor failure. Instead, FA laboratories combine multiple complementary techniques.
Optical microscopy is one of the simplest physical-analysis methods and can help identify relatively large defects such as:
When defects are too small for optical inspection, electron microscopy is typically required.
A Scanning Electron Microscope (SEM) provides high-resolution imaging of semiconductor surfaces and cross sections.
SEM can be particularly valuable for investigating:
SEM can also be combined with analytical techniques such as EDS/EDX to obtain elemental information from suspicious material.
Read more: SEM Analysis for Semiconductor Failure Analysis
Focused Ion Beam, or FIB, is one of the most powerful tools used in advanced semiconductor physical analysis.
A focused ion beam can selectively remove material from a specific region, allowing engineers to expose buried structures.
Applications include:
JEOL describes FIB milling as particularly important for semiconductor failure analysis because a selected region can be precisely thinned while the milling operation is monitored.
FIB can also be integrated with SEM imaging in a combined FIB-SEM system.
AnySilicon already covers this topic in more detail:
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When a defect must be studied at extremely small dimensions, Transmission Electron Microscopy (TEM) may be required.
TEM can provide very high-resolution structural information and is especially useful for advanced semiconductor technologies where defects may exist within extremely small features or interfaces.
A thin sample, often called a lamella, normally needs to be prepared before TEM analysis. FIB is widely used to prepare site-specific TEM samples from semiconductor structures.
TEM can help investigate:
Read more: TEM Analysis of Semiconductor Devices
Sometimes an unusual particle, residue or layer is discovered during SEM examination.
Energy Dispersive X-ray Spectroscopy, usually abbreviated EDS or EDX, can help determine the elemental composition of the region.
This can be useful when investigating:
JEOL notes that SEM combined with EDS is suitable for localized elemental analysis at micrometer-scale regions, while other surface-analysis methods may be more appropriate when higher surface sensitivity is required.
Read more: EDS/EDX Analysis in Semiconductor Failure Analysis
The analytical technique describes how the device is investigated. The failure mechanism describes what physically happened to the device. Some frequently investigated semiconductor failure mechanisms include:
Electrostatic discharge can expose semiconductor structures to a short-duration electrical event capable of damaging sensitive devices. The resulting damage can be highly localized. Read more: ESD Failure in Integrated Circuits
Electrical overstress occurs when a device experiences electrical conditions beyond its intended limits.
Potential causes include:
EOS can produce obvious catastrophic damage, but interpreting the original cause can require careful analysis. Read more: Electrical Overstress (EOS) Failure in ICs
Electromigration involves movement of atoms in conductive structures under high current-density conditions and can eventually contribute to void formation, resistance changes or interconnect failure.
NIST describes electromigration as a semiconductor failure mechanism associated with ionic movement in metal thin-film conductors, accelerated by elevated temperature and current density. Read more: Electromigration in Integrated Circuits
Dielectric layers electrically isolate different semiconductor structures. If a dielectric loses its insulating properties, the result may include:
Failure analysis may therefore combine electrical localization with high-resolution physical examination of the suspected region. Read more: Gate Oxide Breakdown and Dielectric Failure
Modern integrated circuits contain many levels of increasingly complex interconnect.
Failures may involve:
Electrical localization followed by cross-sectioning, SEM or FIB analysis can help determine the physical cause.
Foreign material and chemical contamination can affect semiconductor structures and package interfaces. Surface-analysis methods can help determine the composition and chemical state of suspicious material. Surface-related effects such as corrosion and reactions can directly influence performance and reliability. Read more: Corrosion and Contamination Failures in Semiconductor Devices
Not every semiconductor failure originates inside the silicon. Failures can also occur within the package.
Examples include:
NIST identifies fracture, delamination, fatigue cracking and void formation among reliability issues that can arise from interactions between materials in complex electronic structures.
Related guides:
Bond Wire Failure: Causes and Failure Analysis
Die Attach Failure in Semiconductor Packages
Solder Joint Failure in Semiconductor Packages
Semiconductor failure analysis becomes increasingly difficult as device structures become smaller and more complex.
Modern technologies can involve:
Three-dimensional structures make defect localization and cross-sectional analysis particularly important. JEOL notes that 3D observation at nanometer-scale resolution is important for development and failure analysis of newer semiconductor architectures.
NIST also highlights the need for new failure-analysis and reliability approaches as semiconductor systems move toward 3D and heterogeneous integration. This creates growing demand for combinations of techniques rather than reliance on a single analytical instrument.
Power devices can experience failure mechanisms associated with high voltage, high current density and elevated temperature. Failure-analysis requirements may therefore differ from those of digital logic devices.
AnySilicon plans dedicated guides covering:
Wide-bandgap devices such as SiC and GaN can require specialized physical-analysis workflows involving techniques including FIB-SEM and TEM.
Packaging technology has also become substantially more sophisticated. Depending on the device, the failure may occur in the silicon, die attachment, interconnect, substrate, solder joint or another part of the package.
Dedicated analysis may be required for:
Chiplet and 2.5D/3D IC Failure Analysis
Choosing the right FA partner depends heavily on the device and failure. Important questions include:
Analyzing a mature-node analog IC can require different expertise from analyzing a 3D advanced-node processor or SiC power MOSFET.
Depending on the problem, required capabilities might include:
Fault localization and physical analysis are often closely connected. Having both capabilities can simplify the investigation.
Preparing the correct region for analysis can be just as important as the analytical instrument itself.
For production-line problems or major customer failures, turnaround time can be extremely important.
A good FA report should clearly separate observations, evidence, failure mechanism and root-cause conclusions.
Read our dedicated guide:
How to Choose a Semiconductor Failure Analysis Lab
Before requesting analysis, collect as much relevant information as possible.
Ideally provide:
Do not unnecessarily modify, clean, open or electrically stress a failed device before consulting the FA laboratory, because doing so can potentially alter evidence.
Read more: What Information Should You Send to a Failure Analysis Lab?
There is no standard price for semiconductor failure analysis.
Cost depends heavily on:
A relatively simple inspection and electrical characterization can therefore be very different from an advanced investigation requiring nanoprobing, site-specific FIB preparation and TEM analysis.
Read more:
How Much Does Semiconductor Failure Analysis Cost?
Semiconductor failure analysis is the systematic investigation of a semiconductor device that has failed or behaves abnormally. The objective is to locate the failure, identify the physical or electrical failure mechanism and determine the underlying root cause.
Electrical Failure Analysis (EFA) characterizes electrical behavior and helps localize the failing region.
Physical Failure Analysis (PFA) physically examines the suspected region using microscopy, cross-sectioning and material-analysis techniques.
The two are often used sequentially.
Common techniques include electrical testing, X-ray imaging, acoustic microscopy, emission microscopy, thermal analysis, SEM, FIB, TEM, EDS/EDX, nanoprobing and various forms of surface analysis.
The correct combination depends on the failure.
Not always.
Visual inspection, electrical characterization, X-ray and some other techniques can be non-destructive.
Techniques such as decapsulation, cross-sectioning, delayering, FIB milling and TEM sample preparation can alter or destroy at least part of the sample.
The ultimate purpose is usually to identify the root cause of a failure so corrective action can be taken in semiconductor design, manufacturing, assembly, qualification, handling or system operation.
Yes.
Failures can originate from package cracking, delamination, bond wires, die attach, solder joints, moisture, contamination, thermal stress and other package-related mechanisms rather than from the semiconductor circuitry itself.
The most important result of failure analysis is not a microscope image.
It is an explanation.
A useful analysis should establish a defensible connection between:
Observed electrical failure → localized defect → physical damage → failure mechanism → root cause
Finding a damaged transistor or metal line without understanding why it was damaged may leave the real problem unresolved.
This is why semiconductor failure analysis often requires engineers from several disciplines, including:
The analysis should ultimately provide information that can prevent the failure from recurring.
If you have a failed IC, semiconductor device, wafer or package and need external analysis, AnySilicon can help connect you with suitable semiconductor failure-analysis companies and laboratories.
Whether your requirement involves electrical failure analysis, package inspection, decapsulation, SEM, FIB, TEM, material characterization or complete root-cause analysis, tell us about the device and the problem.
Request Failure Analysis Support →
Provide a short description of the failed device and the problem, and AnySilicon can help identify suitable failure-analysis partners.
