Photon Emission Intensity Analysis for Leakage Source Identification

Defect isolation and failure analysis is a key factor that drive development and manufacturing yield improvements in semiconductor packaging industry. From a manufacturing point of view, ensuring adequate package reliability is becoming more challenging due to increasing packaging complexity and a more pronounced impact from material physical property mismatch among packaging materials and components. The task of isolating defects and finding root cause is further complicated by ever shrinking feature sizes within the device and/or package, already approaching the nanometer range in contemporary semiconductor packages. Conventional failure analysis techniques such as physical cross sectioning or micro-cutting using focused ion beams(FIB) are sometimes no longer sufficient to find these defects. Both physical cross section and FIB are only capable of exposing the defect in two dimensions (x and y directions), which makes pinpointing the defect in depth, i.e., the z direction, extremely difficult when dealing defects with micron and submicron size. Additional complications are many times introduced during conventional sample preparation, which can introduce undesirable artifacts associated with the module and/or device depackaging. These artifacts may mask the true defects, or lead to misinterpretation of the true cause of failure. In this work, it has been determined that a three-dimensional failure analysis method is critical for finding some defects in silicon packages. For example, xenon difluoride (XeF2) has excellent selectivity to silicon and provides efficient material removal by chemical reaction, generating gaseous by-products that can be readily exhausted [1]. Furthermore, XeF2 has very little reaction with non-silicon materials, such as SiO2, and the metals and polymers commonly used in semiconductor devices and packages. This paper reports the application of XeF2 as an effective failure analysis technique to reveal defects in silicon packages. The mechanism of selective reaction between XeF2 and Si is discussed and key design features of the failure analysis tool are presented. The paper also highlights a few case studies which advantageously utilize XeF2 etching to expose defects. XeF2 was especially effective in detecting the source of electrical leakage in 3D packages having Through Silicon Via (TSV) structures. Due to its high etching selectivity to silicon, the leakage area in electrically failing samples was found to be due to damage of the TSV liner (passivation layer material) and further analysis reveals a three dimensional view of the TSV defect. With the addition of XeF2 etching, further characterization of defects by traditional methods such as FIB micro cutting also becomes more practical. The work suggests that a wider application of Si removal via XeF2 can be achieved by combining mechanical milling of bulk silicon followed by a final, low stress, silicon removal by XeF2 etching.

Study of spontaneous photon emission without external or artificial stimulation in biological tissues and cells in vivo is impeded by the extremely low intensity of such biophoton emission in many subjects and systems of interest. The aim of our research project is the research and development of improved means of detecting these biophoton phenomena and the study of their characteristics. We describe here recent developments in highly sensitive photon counting technique and measurement of ultraweak photon emission. As an illustration, we discuss two areas of current research: 1) Studies of the effects of various solutions of germination promoter on ultraweak photon emission in soybean have been made. Among inhibitors examined, KCN and EtOH were found to enhance photon emission intensity. 2) The effect of environment (oxygen and nitrogen) and scavenger solutions on ultraweak photon emission intensity in soaked soybean was examined and found to be oxygen-dependent. Thus it is thought that the active oxygen species were participated in the ultraweak photon emission of soybeans. The mechanisms underlying these phenomena and the results of further studies will be discussed.

Failure analysis (FA) is a basic and effective method to obtain the physical and failure information of electronic components and circuits. Most of these information can provide many useful evidences for prognostic and system health management (PHM) of electronic products. To obtain these information, many failure analysis techniques are used. This paper focuses on analyzing the relationship between FA techniques and PHM system. To test and verify the availability of the relationship between FA techniques and PHM system, a failure analysis case of an Intelligent Power Module (IPM) is used to study the relationship. This IPM contains six insulated gate bipolar transistors (IGBTs) and there are obvious burnout indications on most of them after failure. With the process of failure analysis, the key information, such as component's structure, sensitive parameters are identified. These results persuasively prove that FA techniques can provide much information to PHM system, including PoF and data-driven methods.

The focused ion beam system has been widely used as a critical failure analysis tool as microprocessor technology advances at a ramping speed. It has become an essential step in failure analysis to reveal physical defects after electrical fault isolation. In the highly competitive and challenging environment prevalent at present, failure analysis throughput time is of utmost important. Therefore, a quick, efficient and reliable physical failure analysis technique is needed. This paper discusses the applications of FIB as a defect localization and root cause determination tool through the passive charge contrast technique and pattern FIB analysis.

Insect spontaneous ultraweak photon emission as an indicator of insecticidal compounds

Root cause failure analysis of lithium-ion batteries provides important feedback for cell design, manufacture, and use. As batteries are being produced with larger form factors and higher energy densities, failure analysis techniques must be adapted to characteristics of the specific batteries. This paper will discuss the significance of melted copper in lithium-ion battery cells that have experienced thermal runaway and how the interpretation of such evidence has evolved over time. Specialized testing techniques that may prove helpful in determining the root cause of battery failures will also be described.

CADless laser assisted methodologies for failure analysis and device reliability

The aim of the investigation is to determine the effect of microwave pretreatment of wheat seeds on the resistance of seedlings to osmotic stress. Changes in biophysical, physiological and biochemical characters were measured. The results showed: (1) The magnetic field intensity and seeds temperature increased progressively with microwave pretreatments of 5, 10, 15, 20 s and 25 s compared with controls. Although each microwave pretreatment resulted in an increase in alpha-amylase activity and photon emission intensity, the increase of alpha-amylase activity and photon emission intensity was maximal at a microwave pretreatment of 10 s. (2) Osmotic stress induced by PEG treatment enhanced the concentration of malondialdehyde, while decreasing the activities of nitricoxide synthase, catalase, peroxidase, superoxide dismutase and the concentration of nitric oxide, ascorbic acid, glutathione in the seedlings compared with controls. However, compared to osmotic stress alone, in the seedlings treated with microwave irradiation plus osmotic stress the concentration of malondialdehyde decreased, while the activities of nitricoxide synthase, catalase, peroxidase, superoxide dismutase and the concentration of nitric oxide, ascorbic acid and glutathione increased. These results suggest that a suitable dose of microwave radiation can enhance the capability to eliminate free radicals induced by osmotic stress in wheat seedlings resulting in an increase in resistance to osmotic stress.

International exercise on 124Sb photon emission intensities determination

Low power mode current is a very important parameter of most microcontrollers. A non-production prototype microcontroller had high current issues with certain SRAM modules which were produced using a new memory compiler. All devices were measuring 100’s μA of low power mode current which was an order of magnitude higher than the requirement. Many failure analysis (FA) techniques had to be used to determine the root cause: Optical Beam Induced Resistance Change (OBIRCh), photo emission microscopy (PEM), microprobing, and nanoprobe device characterization. Transistor models and measurements of probe structures from the effected lots both predicted that the device low power mode current would meet expectations; however, all first silicon samples had elevated low power mode current. A knowledge of low power design methodology was needed to ensure all issues were discovered.

Leakage current study and relevant defect localization in integrated circuit failure analysis

Phosphenes are experienced sensations of light, when there is no light causing them. The physiological processes underlying this phenomenon are still not well understood. Previously, we proposed a novel biopsychophysical approach concerning the cause of phosphenes based on the assumption that cellular endogenous ultra-weak photon emission (UPE) is the biophysical cause leading to the sensation of phosphenes. Briefly summarized, the visual sensation of light (phosphenes) is likely to be due to the inherent perception of UPE of cells in the visual system. If the intensity of spontaneous or induced photon emission of cells in the visual system exceeds a distinct threshold, it is hypothesized that it can become a conscious light sensation. Discussing several new and previous experiments, we point out that the UPE theory of phosphenes should be really considered as a scientifically appropriate and provable mechanism to explain the physiological basis of phosphenes. In the present paper, we also present our idea that some experiments may support that the cortical phosphene lights are due to the glutamate-related excess UPE in the occipital cortex.

The article presents the results that can be a prerequisite for the introduction of a pre-sowing electrotreatment of winter rape seeds into the production process. The results of photon emission by rape seeds after electrical stimulation are highly correlated with the data obtained during determination of its sowing qualities and field germination. Absorption and transformation of the energy of the external electric field during the electrostimulation of winter rape seeds occurs non-linearly. It was established that the main transformations take place during the first 15 s, regardless of the electric field intensity. Relaxation processes were revealed, which become dominant after 15 s of electrical stimulation. The pre-sowing electrical stimulation improved the sowing properties of winter rapeseed. The highest values of germination energy and laboratory germination (87% and 96%), which exceeded the control by 9% and 8%, were obtained under the treatment mode E=2 kV·cm −1 , t=30 s. Pre-sowing electrostimulation of winter rape seeds at optimal conditions helps to increase its field germination. Under the treatment mode E=2 kV·cm −1 , t=30 s was 90%, and with E=3 kV·cm −1 , t=30 s – 83% versus 79.7% in the control.

In this study, we assessed the impact of exposure to scalar coherence fields on the vitality of various organic and inorganic compounds, as measured by their biophoton emission. Samples were irradiated with scalar waves for different exposure durations—30 minutes, 2 days, and 7 days. The results show that prolonged exposure (particularly at 2 and 7 days) maintains or even enhances the intensity of spontaneous photon emission, which serves as an indicator of a high energetic state or sustained vitality.

Failure analysis plays an important role in yield improvement during semiconductor process development and device manufacturing. It includes two main steps. The first step is to find the defect and the second step is to identify the root cause. In the past, failure analysis mainly focused on the first step, namely how to find the defect for a failure; because in the previous generations of technology, once the defect was found, its root cause was relatively easy to be understood. As the current advanced semiconductor technology has become tremendously complicated, especially 3D devices, like FinFET, a defect found by failure analysis can be substantially transformed from its original defect by subsequent processes and can be totally different from its origin in size and shape. Thus, sometimes, the second step, identifying the root cause for a defect becomes more challenging and takes more time than the first step. With combination of failure analysis and inline inspection, it enables us to establish the relationship between the failure analysis defect and an in-line defect. This can link the defect for a device functional failure to its source layer and process step more quickly, leading to fast root cause identification. In this paper, the methodology was validated by fast identification of the root causes for three case studies in the latest FinFET technology.