New heterogeneous 3D integration schemes and continuing miniaturization of semiconductor packaging components, such as micropillars, are driving demand for substantive changes to conventional PFA (physical failure analysis). In particular, desired performance capabilities include the ability to nondestructively determine failures within seconds to minutes. New tools should be quantitative, have sufficient resolution to determine sub-micron sized defects and voids in TSVs at the wafer or package level. It should also measure thickness and their material composition of multilayer structures above the wafer surface, such as microbumps, or those below the surface including UBM and RDL. In this paper we are introducing a novel x-ray fluorescence microscope technique capable of solving the above applications in advanced packaging for PFA and process development. The same technique can also be applied in the front end metrology of new gate materials, 3D FinFET structures within test structures in patterned wafers. Characterization of sub nanoscopic changes (sensitivity of sub-angstrom) in film and dopants deposited in 3D structures will also be shown. With its high sensitivity for trace materials, contamination analysis of post hard mask residue, post metal etch residue especially in high aspect ratio structures is also possible.

The metal thickness of surface finish is an important consideration when plating on microelectronics. Metal finish thickness should comply with specification requirements to prevent serious reliability concerns. The thickness of metallic coatings is routinely determined by X-ray fluorescence (XRF) spectrometry. For conventional XRF instrumentation, typical focal spot sizes at the sample surface range in diameter from several hundred micrometers up to several millimeters. Micro- XRF focuses or collimates the X-ray beam to significantly smaller spot sizes, ranging from ~30 µm to 2 mm, thus obtaining a representative average of layer properties both at the surface and in-depth layers. This is a critical property for application in semiconductor industry where feature size is becoming progressively smaller. This work describes how a mid-range cost conventional XRF tool can be utilized for small spot size thickness measurement with the addition of a 0.25 mm diameter collimator.

We describe a technique for mapping the distribution and concentrations of trace elements, most notably with capabilities of achieving 1-10 parts per million sensitivities within 1 second and at <8 μm resolution. The technique features an innovative, high flux microstructured x-ray source and a new approach to x-ray optics comprising a high efficiency twin paraboloidal x-ray mirror lens. The resulting ability to acquire dramatically higher sensitivities and resolution than conventional x-ray fluorescence approaches, and at substantially higher throughput enables powerful compositional mapping for failure analysis, process development, and process monitoring.

The analysis of thin layers in semiconductor components represents a central point in the quality control of semiconductor companies. Not only to control production processes, but to successfully operate also reverse engineering, reliable thin-film measurement methods are essential. In this work, non-destructive thin film EDX (energy dispersive X-ray micro analysis) software and μXRF (micro x-ray fluorescence analysis) were compared with TEM analysis. These methods ensure a high lateral resolution which is essential in the analysis of semiconductor structures. As an example, four different, for the semiconductor industry interesting, very thin coating systems in the nanometer range have been tested. In the individual cases best TEM detector contrast settings could be found, as well as optimum fluorescence lines settings on the EDX to minimize the errors. The TEM measurements, in thickness and composition, were compared to the thin film EDX software and the μXRF method results to determine their accuracy. It turns out that depending on the layer system recalibration with multilayer standards or at least with elemental standards is recommended. It could be shown that with μXRF and thin film EDX a reliable, rapid and non-destructive layer analysis is possible.

Counterfeit components have been defined as a growing concern in recent years as demand increases for reducing costs. In fact the Department of Commerce has identified a 141% increase in the last three years alone. A counterfeit is any item that is not as it is represented with the intention to deceive its buyer or user. The misrepresentation is often driven by the known presence of defects or other inadequacies in regards to performance. Whether it is used for a commercial, medical or military application, a counterfeit component could cause catastrophic failure at a critical moment. The market for long life electronics, based on commercial off the shelf (COTS) parts, such as those used in medical, military, commercial depot repair, or long term use applications (e.g. street and traffic lights, photovoltaic systems), seems to create a perfect scenario for counterfeiters. With these products, components wear out and need to be replaced long before the overall product fails. The availability of these devices can be derived in many ways. For example, a typical manufacturer may render a component obsolete by changing the design, changing the functionality, or simply discontinuing manufacture. Also, the parts that are available after a design has been discontinued are often distributed by brokers who have very little control over the source or supply. Recycling of devices has also emerged as a means of creating counterfeit devices that are presented as new. And finally, as demand and price increase, the likelihood of counterfeits also increases. This paper will address the four unique sources of counterfeit components and insight into how they occur. Detection methodologies, such as visual inspection, mechanical robustness, X-Ray, XRF, C-SAM, Infrared Thermography, electrical characterization, decapsulation, and marking evaluations, will be compared and contrasted, as well as multiple examples of counterfeit parts identified by DfR.

The electronics supply chain is being increasingly infiltrated by non-authentic, counterfeit electronic parts, whose use poses a great risk to the integrity and quality of critical hardware. There is a wide range of counterfeit parts such as leads and body molds. The failure analyst has many tools that can be used to investigate counterfeit parts. The key is to follow an investigative path that makes sense for each scenario. External visual inspection is called for whenever the source of supply is questionable. Other methods include use of solvents, 3D measurement, X-ray fluorescence, C-mode scanning acoustic microscopy, thermal cycle testing, burn-in technique, and electrical testing. Awareness, vigilance, and effective investigations are the best defense against the threat of counterfeit parts.

X-ray fluorescence imaging is a novel non-destructive method to obtain sub-100nm spatial resolution elemental maps with short data acquisition times. The method has a wide range of applicability in the field of semiconductor manufacturing and semiconductor failure analysis. Imaging of copper interconnects on ICs for the location of voids and shorts is one particular application that is relevant for current and future needs of nondestructive inspection and failure analysis of backend processes.

The Directive 2002/95/EC (referred as ROHS) of the European Parliament and of the Council restricts the use of certain hazardous substances in electrical and electronic equipment. This article reports on a fast and inexpensive methodology for rapidly screening entire electronic assemblies that acts as a high-level screen for obvious ROHS violations. Using this methodology, this lab has been able to check entire product lines for basic ROHS compliance and has identified many cases where vendors needed to be informed of ROHS violations before a product could be certified as ROHS compliant. Four tests are employed. Each of them is described, along with the basic theory behind the test: pre-screening with x-ray fluorescence spectroscopy and electron dispersion spectroscopy; detection and identification of polybrominated biphenyl ethers using gas chromatography - mass spectrometry; and chromium 6 colorimetric testing based on diphenylcarbazide.

This paper correlates the reseat failure rates of a PCI option card to the use of thin gold plating across the contact fingers. This failure mechanism results in increased contact resistance and is often misdiagnosed due to its intermittent failure mode. As many new manufactures appear in Asia, the push for global competitiveness to achieve high volume and reduced costs can result in insufficient plating finishes being applied to the contact fingers. Compounding this problem is the fact the many companies use multiple raw board suppliers to meet these volume requirements. Many times the end user of the option card is unaware of the wide variation in contact plating thickness that may be present from one raw board source to another. Intermittent failures are one of the most common defects experienced in high volume assembly. Unless properly diagnosed, these failures can be attributed to finger debris, rework flux, solder paste contamination and even connector related issues. The typical fix, whether approved by the process or not, is for the manufacturing assembler to reseat all of the option cards and memory into the Motherboard connector sockets. Unless the proper troubleshooting approach is followed, isolating the true root cause of the actual failure can be missed. The difficulty in identifying the reseat problem is compounded by the fact that the failures are often intermittent in nature. While reseating may temporarily achieve sufficient mating between the board’s contact fingers and the connector contacts, it provides no long term fix. These unnecessary reseats also reduce the long-term durability of already thin plating affecting customer satisfaction and warranty costs. In the paper, we will expand on the theory behind the XRF plating thickness testing, including: • System theory • Test calibration • Part orientation • Test measurement criteria Additional analysis of metallurgical cross-sectioning was performed to correlate the XRF test readings to the actual plated layers. The measurements were completed by use of a SEM (Scanning Electron Microscopy).