Zenpire  Products 
  iFAB-Defect
  iFAB-Test   
  iFAB-Setup    
  iFAB-Bit 
  iFAB-Pixel
  iFAB-Utilities   
  iFAB-Central 
  iFAB-FA         

Possessing most of the capabilities of iFAB-Test, iFAB-FA (Failure Analysis) is a soon-to-be-released module that will be used to assist in the failure analysis of circuits on a wafer. iFAB-FA is a microscope stage driver with a advanced positioning and circuit locating capability. Combined with highly accurate stages such as the Kensington MS-4, and iFAB-Bit bit positioning and address scrambling plug-ins, iFAB-FA can drive the stage to individual bit cells or predefined coordinates on a wafer. Able to read many of the most common defect location files (click here to list), iFAB-FA can load a defect map from several layers of processing, after a few short steps to align the wafer and locate a reference point, defects are positioned under a microscope by clicking on the defect in the computer display.

Additionally, locations can be saved to a location file for easy recall at a later process step or for another wafer. These location files also enable a sampling plan which can be used to automate inspections of probe marks at wafer test. Deprocessing engineers would use the setup files to assist in positioning the scope on a features after each layer has been etched away.

Like all iFAB modules, iFAB-FA runs on most popular computer platforms (Windows 95,98,NT; Solaris; HP-UX; Linux; Apple). In each of these platforms, drivers have been written to link iFAB's Java code to the serial, ethernet, and soon GPIB connections (via the ethernet or serial interface). Zenpire merely links its wafer display capabilities with a newly developed, multithreaded interface controller to conceive iFAB-FA. Much like iFAB-Test, wafer handlers are selected by the failure analysis engineer using iFAB's plug-in architecture employing Java Beans. Because iFAB-FA uses the same software objects as other iFAB modules, iFAB-FA represents the first step at a common piece of software which links front-end and back-end processing with data viewing and equipment control capabilities.

iFAB-FA is not yet released, contact Zenpire Sales for availability.

• Runs on all major platforms
• Common interface for a variety of microscope stations
• Easy to use interface (engineers AND operators can use)
• Point and click interface to direct scope to locations on a wafer
• Can load defect files (click here to list); click on defect to move under scope
• Loads iFAB-Bit device setup files to allow point and click interface to drive to and/or identify bit cell locations (accounting for address scrambling)
• Similar interface to all other iFAB modules (Defect, Setup, Bit, Test)
• Magnification of defect and bit maps allow for extremely accurate positioning of scope
• Highly accurate location can be saved for recall at a later time and other microscopes

• Product engineers wanting a system to quickly review inline inspection defects or failing die structures under a microscope
• Process engineers wanting to observe circuit features after each process step or for off-line visualization of defects determined at inspection
• Reliability/failure analysis engineers desiring an easy method to consistently locate features during wafer deprocessing
• Test floor production manager needing a system for a sample inspection of probe marks

After a yield engineer notices a yield shortfall on a wafer, he might decide to make visual observations of failing die. The yield engineer would call up iFAB-FA on a computer connected to a high precision microscope. After calling up the yield map (in the iFAB Bin Classification XML format) and displaying the map on the display, the engineer would align the wafer to a point on the wafer display. Desiring to observe die of certain bin codes, the engineer identifies those die via color and clicks on a die of that code driving the stage to that die. While looking on that die under the scope, the engineer can save locations of interest to a list. Once the engineer has saved several features of interest, he can refer back to each element on the list and quickly jog to that position comparing features. The list can be saved to a file for recall at a later time or for another scope.

Using the same setup procedure as above, the yield engineer would also load the device Java Beans as created in the iFAB-Bit module. The beans contain the bit address scrambling algorithms and locations of the bits within the die. When iFAB-FA knows this information, it is able to drive the wafer handler stage to bit locations within the die. For example to look at the bit failure of die "1,2" and test address of X=1443, Y=5446, the engineer merely has to click to the die "1,2" on the display and hand enter address "1443,5446". If aligned properly, the memory cell will be positioned directly under the cross hairs of the microscope.

Alternatively if the engineer is looking for abnormalities observed in a memory array, iFAB-FA is able to unscramble the various addresses of the bit locations under the scope to assist the engineer in locating test peculiarities.

How does a yield group identify defects as the definite cause for circuit failures. Most likely determination is performed by deprocessing. As we all know, deprocessing is a slow and tedious job. The frustrations of removing layers (under-removing and over-removing) and making observations under a microscope can make this an undesirable task, especially if this is above and beyond normal product responsibilities. iFAB-FA is used to load files as created by the defect inspectors and display the defects. When the defects are listed on the display and the wafer is aligned, the engineer clicks on the defect to move the microscope stage to that location. Defects of interest can be saved to a location list for recall after the next layer is removed.

iFAB-FA reduces the challenges of deprocessing by lessening the difficulties in defect location for visualization.

None