The purpose of acoustic screening is to weed out components with internal structural defects such as delaminations and voids before surface mounting.  Counterfeit plastic packaged ICs are typically discovered when a Sonoscan® C-SAM® acoustic microscope is scanning trays of supposedly new plastic IC packages.

The operator may notice that some of the plastic IC packages have defects. When he looks closely at the acoustic images, he notices something else – that the internal defects look a lot like those one usually sees in IC packages that have been heat damaged or even “popcorned” during a surface mount process.  In addition the internal features may be inconsistent – die size or die orientation, lead frame geometry differences, etc.  The components in the trays may just not look consistent or they may look more like improperly handled devices.

Are these counterfeit parts? To find out more, additional Sonoscan (www.sonoscan.com)  C-SAM methods may be used to inspect the same components by looking for 28 characteristics associated with counterfeit parts, including the following:

    • Evidence of sanding on the surface of the mold compound beneath a “blacktopped” surface.

    • Remnants of an old ink printed label, not completely sanded off, beneath the  ”blacktopped” surface.

    • Remnants of an old laser marked label, not completely sanded off, beneath the  ”blacktopped” surface.

    • The acoustic impedance value of the mold compound.  If the parts are authentic, they should all have the same mold compound and the same acoustic impedance. If some of the parts are counterfeit, they may have come together from many sources, therefore having varying acoustic impedance values.

Along with the original suspicious appearance of the defects, these methods help to identify the authenticity of parts. Unfortunately it is quite common for components such as plastic ICs packages and capacitors to be stripped from “junked” PC boards and cosmetically refurbished for resale as new components.

Although verification of counterfeit status may be aided by optical and x-ray methods, C-SAM acoustic microscopy is unique in that it alone is sensitive to delaminations.

3D IC and Stacked die configurations are often difficult to image with an acoustic microscope because the multiple internal surfaces send back so many echoes and re-echoes from the ultrasound pulsed into the stack. Stacked die makers wanting to check nondestructively for delaminations between layers have often been frustrated by this limitation.

Sonoscan (www.sonoscan.com) has now taken a major step toward resolving this problem with the introduction of its SonoSimulator™ software, which is now a standard feature on the Gen6™ C-SAM® acoustic microscope.

The SonoSimulator determines optimal gate positions and other parameters with far less effort than is possible with the physical stacked parts alone. It also results in higher quality acoustic images.

This powerful new software allows the operator to create a virtual die stack that matches the characteristics of the physical 3D IC or die stack to be inspected, including defects at specified layers.

The virtual defects help determine the optimum placement of gates to image specific levels in the stack. The imaging parameters are then easily transferred to the Gen6 Sonolytics™ software and used to image the physical 3D IC or die stack.

In a short time the best gate positions and other parameters for imaging the physical 3D IC or die stack can be obtained, even by less experienced operators.

Sonoscan’s Dual Scanning™ on the AW300™ automated acoustic imaging system for 300mm wafers utilizes two transducers that simultaneously scan two wafers, providing optimum throughput in production environments.

Sonoscan’s (www.sonoscan.com) transducer electronics have been known as the fastest in the industry for a long time now. Having dual transducers makes it possible for the AW300 to match cycle times for handling and scanning. The system is thus optimized for use in production, and the number of wafers inspected per hour increases.

Only a few millionths of a second are needed for a pulse from the transducer into and back from material interfaces, including defects. During this time, despite its high forward speed, the transducer hardly moves at all relative to the speed of the pulse.

The data collected will identify which devices have anomalies that meet the user’s definition of a “rejectable defect”. A device having a small anomaly in a location that renders it harmless would pass inspection based on the user’s criteria for the automated digital image analysis.

Overall throughput speed is further enhanced by the AW300’s wafer-handling robot that positions wafers very precisely for scanning. Careful placement of the wafers aligns each device for automated analysis, such as wafer map, that will increase productivity by eliminating bad devices.

Sonoscan® has unveiled its newest Lab Model 9600™ C-SAM® acoustic micro imaging system, specifically designed to serve as a general-purpose tool for laboratory/failure analysis work or for low-volume production inspection.

Like the recently introduced technology-laden Gen6™ system, Model 9600 incorporates advanced Sonolytics™ software and its highly-rated graphical user interface. With the Gen6 and the 9600 Sonoscan has raised the performance level for laboratory acoustic microscopes. The 9600 in particular is designed to put Sonoscan quality in the hands of budget-conscious users.

Standard in the 9600 is PolyGate™ analysis software, which has proven its usefulness in imaging multilayer or bulk materials. PolyGate permits the user to set up to 100 individual gates per channel for a sample.

During a single scan, PolyGate produces a separate acoustic image for each gate. Depending on the material, each gate may be as thin as 20 microns.

The 9600 employs a linear motor for X-axis scanning, a tower mounted scan reference platform, and is rated for Class 1000 cleanroom operation. It has a full portfolio of optional features.

Sonoscan’s AW300™ is not limited to inspecting 300mm wafers for internal defects; it can inspect other sizes of wafers and in various carrier configurations. The AW300 was originally designed to automatically inspect 300mm wafers in FOUPs or FOSBs carriers, but due to its “BOLTS compatible” flexibility, smaller wafers can be inspected for defects.

Currently 200mm wafers being handled in SMIFs, Cassettes or FOUPs with 200mm adapter inserts can be inspected.  If you use FOUPs with inserts, the AW300 design is ready to go for 200mm wafer inspection.  For 200mm SMIF carriers the BOLTS compatible loadports only need to be changed to SMIF loadports.  If your 200mm wafers are in cassettes, BOLTS compatible cassette loadports are available, too.

Perhaps you need to inspect even smaller wafers; the cassette loadport configuration can handle 150mm wafers as well.  In addition, wafer film frames can be handled by the AW300 with the proper robot end effector.  

The AW300 by Sonoscan (www.sonoscan.com) has become quite universal and flexible for handling 150 to 300mm wafers.  It can even be configured with two (2) different types of loadports, i.e. a 200mm and 300mm loadport, for users transitioning wafer sizes who want to meet their current and future needs for production wafer inspection.