Counterfeit Parts Recognition and Detection for Failure Analysts

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.

Systematic Defect Identification through Layout Snippet Clustering

Systematic defects due to design-process interactions are a dominant component of integrated circuit (IC) yield loss in nano-scaled technologies. Test structures do not adequately represent the product in terms of feature diversity and feature volume, and therefore are unable to identify all the systematic defects that affect the product. This paper describes a method that uses diagnosis to identify layout features that do not yield as expected. Specifically, clustering techniques are applied to layout snippets of diagnosis-implicated regions from (ideally) a statistically-significant number of IC failures for identifying feature commonalties. Experiments involving an industrial chip demonstrate the identification of possible systematic yield loss due to lithographic hotspots.

Fast Turn-around Failure Analysis of Metal Interconnection Using FIB and LA ICP-MS

This paper introduces our effort in failure analysis of a 200 nm thick metal interconnection on a glass substrate and covered with a passivation layer. Structural damage in localized areas of the metal interconnections was observed with the aid of focused ion beam (FIB) cross-sectioning. Laser ablation inductively coupled plasma mass spectroscopy (LA ICP-MS) was then applied to the problematic areas on the interconnection for chemical survey. LA ICP-MS showed direct evidence of localized chemical contamination, which has likely led to corrosion (or over-etching) of the metal interconnection and the assembly failure. Due to the high detection sensitivity of LA ICP-MS and its compatibility with insulating material analysis, minimal sample preparation is required. As a result, the combination of FIB and LA ICP-MS enabled successful meso-scale failure analysis with fast turnaround and reasonable cost.

The Novel Dopant Profile Inspection Methodology by FIB

Dopant profile inspection is one of the focused ion beam (FIB) physical analysis applications. This paper presents a technique for characterizing P-V dopant regions in silicon by using a FIB methodology. This technique builds on published work for backside FIB navigation, in which n-well contrast is observed. The paper demonstrates that the technique can distinguish both n- and p-type dopant regions. The capability for imaging real sample dopant regions on current fabricated devices is also demonstrated. SEM DC and FIB DC are complementary methodologies for the inspection of dopants. The advantage of the SEM DC method is high resolution and the advantage of FIB DC methodology is high contrast, especially evident in a deep N-well region.

Advanced IR-OBIRCH Analysis Technique for High Isb Failure Analysis

IR-OBIRCH (Infrared Ray – Optical Beam Induced Resistance Change) is one of the main failure analysis techniques [1] [2] [3] [4]. It is a useful tool to do fault localization on leakage failure cases such as poor Via or contact connection, FEoL or BEoL pattern bridge, and etc. But the real failure sites associated with the above failure mechanisms are not always found at the OBIRCH spot locations. Sometimes the real failure site is far away from the OBIRCH spot and it will result in inconclusive PFA Analysis. Finding the real failure site is what matters the most for fault localization detection. In this paper, we will introduce one case using deep sub-micron process generation which suffers serious high Isb current at wafer donut region. In this case study a BEoL Via poor connection is found far away from the OBIRCH spots. This implies that layout tracing skill and relation investigation among OBIRCH spots are needed for successful failure analysis.

Fault Localization of Power-Ground Short via Signal Injection and Oscilloscope Technique

For those attempting fault isolation on computer motherboard power-ground short issues, the optimal technique should utilize existing test equipment available in the debug facility, requiring no specialty equipment as well as needing a minimum of training to use effectively. The test apparatus should be both easy to set up and easy to use. This article describes the signal injection and oscilloscope technique which meets the above requirements. The signal injection and oscilloscope technique is based on the application of Ohm's law in a short-circuit condition. Two experiments were conducted to prove the effectiveness of these techniques. Both experiments simulate a short-circuit condition on the VCC3 power rail of a good working PC motherboard and then apply the signal injection and oscilloscope technique to localize the short. The technique described is a simple, low cost and non-destructive method that helps to find the location of the power-ground short quickly and effectively.

Application of Lock-in Thermography on PCB for Fault Localization and Validation of Failure Mechanism Due to External Discrete Component Variation

This paper demonstrates the use of a real time lock-in thermography (LIT) system to non-destructively characterize thermal events prior to the failing of an integrated circuit (IC) device. A case study using a packaged IC mounted on printed circuit board (PCB) is presented. The result validated the failing model by observing the thermal signature on the package. Subsequent analysis from the backside of the IC identified a hot spot in internal circuitry sensitive to varying value of external discrete component (inductor) on PCB.

Copper to Aluminum Bonding: IMC Characterization through New Mechanical Sectioning Methods

This paper presents a mechanical cross-sectioning approach that produces an image clarity not yet demonstrated in published literature. It demonstrates how a critical sequence of polishing, basic slurry optimization and staining, in conjunction with correct imaging parameters can be used to highlight the growth morphology of the intermetallic compound (IMCs). Utilizing this approach, the paper describes the results of a SEM imaging study of the intermetallic formation and growth at the Cu-Al bond interface during thermal ageing for up to 4000hrs at 150 deg C. The paper uses direct SEM imaging to catalog observations which are used to create an initial model for IMC and void growth at the wire bonded interface. It examines the effect of aluminum splash and concludes that growth of intermetallics at the Cu-Al interface is rapid into the bond-pad aluminum than into the Cu-ball, but the growth thickness uniformity is much higher into the Cu-ball.

A Novel Junction Profiling Methodology

Currently many methods are available to obtain a junction profile of semiconductor devices, but the conventional methods have drawbacks, and they could be obstacles for junction profile analysis. This paper introduces an anodic wet etching-based two-dimensional junction profiling method, which is practical, efficient, and reliable for failure analysis and electrical characteristics evaluation.

Quality Evaluation Techniques of Solar Cell Module

We have developed a process diagnostics system for photovoltaic energy modules based on standard methods and practices already developed for LSI and MEMS technologies. This paper provides a description of methods used to ensure the conformation of solar cell modules to the rigors of high-quality manufacturing necessary for reliable photovoltaic energy production when exposed to long-term environmental use. We have verified the possibility of inspecting each solar cell and the module assembly in detail for several photovoltaic technologies, specifically monocrystalline Si, polycrystalline Si, and CuInxGa1-xSe2 An objective set of criteria for the quality of each module can be provided by this method for use in module selection by consumers. Moreover, the quality of conformance and reliability data can be used as feedback to the manufacturer to minimize the number of defects created during manufacturing process and ameliorate their effects.