Failure Analysis with Curve Tracing

RTI has a long-standing relationship with failure analysis (FA) engineers. We have a wide range of test solutions for Failure Analysis of any kind of electronic device providing the critical connection between the device under test (DUT) and the tools examining it. Our FA test solutions consider the unique needs of fault localization, device visibility, and surface access.

RTI has a global footprint in the FA lab, our solutions are used by most semiconductor companies for analysis and characterization purposes. Lab Grade and durable sockets are built to last and capable of being serviced, DUT boards and fixture interface products offer a myriad of configurations to fit your devices and toolset.

The MultiTrace curve tracer is the perfect tool for failure analysis. It has a high degree of flexibility for electrically characterizing devices to find evidence of failure. It pairs nicely with RTI fixture products and allows for a turnkey solution that simplifies communication with RTI enabling effective and rapid problem solving through informed customer support.

Curve Tracing; the Standard of Non-Destructive Testing

Curve tracing is often the first and sometimes the only failure analysis operation on devices received at an FA lab. It is considered universal and non-destructive when low power settings are used. The data it provides describes the electrical connection at the pin under controlled repeatable conditions that can be compared to other device results. Curve tracing can describe leakage failures with great precision and describe opens and shorts failures readily. With a more complex setup, supply current can be measured and more test conditions can be tried.

MultiTrace and Failure Analysis

MultiTrace curve tracer failure analysisThe MultiTrace is RTI’s solution to the failure analysis challenge. This Automated DC characterization system is packed with software that makes curve tracing a complex high pin count device a simple and rapid test. Automation reduces the time it takes to characterize devices. It enables more test conditions to be tried and it improves repeatability and reproducibility of results and provides a wide view of the device continuity results in a single glance.

The MultiTrace software allows the user to save all results and any setup configuration used. This allows for a large library of results which becomes more useful as it grows. Example results from golden devices and debugged test setups can be saved and made available to other users.

Test Applications Developed by and for FA engineers

The MultiTrace hardware and software was invented by an FA engineer for FA engineers. The software has been developed by an FA engineer with input from hundreds of FA engineers. Over 30 years of product improvement has resulted in a well-honed tool for failure analysis.

Manual Switch Box and Failure Analysis

manual switch boxes ganged for failure analysis of high pin count devicesIf automation is not in your budget, RTI offers support for traditional manual curve tracing methods with pathways to upgrades if needed.

RTI’s manual switch box is compatible with several RTI PCB or DUT board product lines. The switch box can be paired with an A/B switch box or cables of various length making it useful in a wide range of applications from curve tracing, IDD testing, or any application with points to measure.

 

manual switch box with overlay panel for custom pin names or numbers
Switch box with Overlay Panel to the right.

The switch box has 96 switches and can be ganged with more switch boxes to access higher pin count applications. Overlay panels can be placed over the switches on the boxes to replace the switch number with device pin numbers making it easier for the operator to keep track of the pin status.

RTI R2 style DUT board with two 100-pin connectors cabled to two switch boxes
Switch boxes with R2 board configuration

The MT Century uses the same cable as the manual switch box, so any DUT board that is compatible with the switch box is automatically compatible with the MT Century. Other cables and adapters can make other configurations of the MultiTrace compatible with the same cables. This means any DUT boards you invest in now, would still be useful as is if you upgraded to any curve tracer.

Yaimachi 96 channel connector and cable
Yamaichi Cable

Various versions of the cables have existed throughout the years. The current RTI design allows ribbon cables to be removed from the cable ends. This allows for easier maintenance if a cable or connector becomes damaged. This also allows you to swap the ribbon for a longer or shorter ribbon.

Indispensable Tool for the FA Engineer

At the heart of the matter is how well the test fixture and DUT board cooperate with the test method to allow a wide range of test conditions and device observations. RTI can help you navigate the maze of choices to find the optimal set of tools to help you get the job done accurately and efficiently.

The high degree of integration between sockets, DUT Boards, fixtures, and measurement tools streamlines the analysis tool selection process by ensuring compatibility, great fit, and high functionality.

Characterization

Characterization is what the FA engineer does when they search for evidence of the failure. The test methods of the MultiTrace are generic enough to be useful on any device and configurable enough to be adapted to most devices. Curve tracing is considered non-destructive and non-invasive.

Screenshot of Unpowered Curve Tracing on Software
Screenshot of Unpowered Curve Tracing on Software

Unpowered curve tracing is used as a precision continuity test. Sometimes referred to as Opens-Shorts Leakage or OSL test the MultiTrace streamlines the setup by only requiring basic input from the operator such as which pins to ground, which pins to test and what voltage range and series resistor to use.

Screenshot of Powered Curve Tracing on Software

As the name implies, the device is powered up and the pins are curve traced or the supply current is measured. The software offers a simple fill-in-the-blanks setup interface and most information is easy to find in the device datasheet like pin names and allowable voltage.

Fault Localization

Fault localization is what the FA engineer does to find the exact structure in the device that has failed. In most cases, the method used to characterize and discover the failure can be used to stimulate the device during this operation.

In most cases, fault localization refers to a collection of techniques that pair a microscope and an electrical fixture that allows the microscope to observe the silicon surface while power is applied to the failure node or whole device. The microscope is typically equipped with a very sensitive camera tuned to visible or IR wavelengths as it looks for a “Hot Spot” which is evidence that a short circuit or other failure is underlying that spot.

RTI sockets have a range of features to support fault localization such as open bottom, open-top, low profile, and short working distance.

In addition to the 100-pin cables used to support the MT Century and the manual switch box, RTI has a variety of other fixtures for other ribbon cable types that support this link to the microscope

Remote test heads are any cable assembly that extends the fixture layer of a test system to the microscope stage and allows the use of interchangeable DUT boards each having a socket with an open-top or open bottom feature.

RTI has remote test heads to support all of our DUT board products and a variety of 3rd party DUT boards, please inquire about your needs.

Probe station interfaces are special fixtures that you can mount in your probe station and they have interchangeable DUT boards with FA capable sockets on top. For example, the 950 Series fixture can be mounted in a probe station and use mini cards for a 96-pin solution. RTI also has higher pin-count probe solutions using the 96/100 pin cable or D-Sub connectors or Ribbon cables of various widths.

Qualification

Qualification testing is usually done by a Reliability engineer but this function or its toolset is sometimes shared with the FA department. RTI FA products are often useful to the Reliability engineer especially when a reliability test leads to a failure that requires analysis.

Although RTI does not make a tool to ZAP the pins we do make many fixtures compatible with DUT boards otherwise compatible with ESD test systems. The MultiTrace offers a fixture compatible with the Verifier 512-pin DUT boards and is an excellent tool to see the damage done to the pins by the ESD testing procedure.

The MultiTrace with 4 and 6-bus configurations are capable of latch-up testing. This test is still essential for companies to qualify their devices for shipment. The MultiTrace offers a greater degree of configurability and data capture than the competition making it a good choice for complex mixed-signal device characterizations.

RTI Test Fixtures for Failure Analysis

Useful for Fault Localizations

Cables and remote fixtures fit on most probe stations and microscopes with large stage areas. Longer cables are available to connect through the pass-through door of a light-tight cabinet as required.

Socket and Fixture Features Useful in Failure Analysis

Visit our main website to learn more about our sockets and fixture solutions.

Open-top Lids: The most requested and most useful option, the FA open-top lid allows for direct access to the surface of the die that is facing the top of the (decapsulated) package.

Open bottom: When the surface of the die needs to be accessed for analysis faces the bottom of the package, then an open bottom socket is needed. Paired with an open bottom DUT board and fixture, this type of analysis can be enabled with only a few mm more working distance than topside applications allow.

Window Lids: Similar in principle to open-top lids, this type of lid is best for WLCSP devices that have no plastic encapsulation. These devices are essentially already decapsulated. The window lid retains the part in the socket while allowing 100% visibility of the backside for IR optical analysis techniques.

Low-profile Lids: Low profile lids allow microscope lenses to get closer to the device which is important for the highest magnification ranges

Accessibility features on DUT boards: In addition to a hole to support open bottom sockets, DUT boards can support several jumper or test point configurations and can be optimized for fixture or bench usage. RTI has many PCB options catering to FA applications

Precision: RTI durable high precision sockets last a long time whether in use or storage, you can count on an RTI socket to get the job done when you need it. High precision ensures an accurate fit for even the tiniest and small pitch devices.

Custom features as required: Modern technology is packing more features into smaller packages. MEMS devices have sensor ports and no-touch areas. RTI has experience with all these unique device types and we have no shortage of ways to deal with them while still allowing analytical access to the device needed for FA applications

Heated or cooled sockets: Failures sometimes only happen under certain thermal conditions. RTI sockets and DUT boards can have a variety of heating and cooling options using both Active and Passive technologies to keep your device at the proper test temperature while allowing analytical access to the device and reliable electrical connection.