Failure Analysis Technology Service

Published on：2018-06-26 Author：ceshi

Our failure analysis laboratory is good at the field of manual probe station, Laser decap, EMMI, IV automatic curve measuring instrument, infrared microscope, semiconductor failure analysis equipment, integrated circuit testing: non-destructive Xing analysis. Introduction of common tools for failure analysis; transmission electron microscopy (TEM); TEM is generally used to analyze sample morphology (morholog); and TEM needs to excite secondary electrons or electrons emitted from the surface of the sample; then some electrons can penetrate the sample by bombarding the sample with this kind of electron beam; for crystalline materials, the sample will cause the diffraction of incident electron beam; for TEM analysis, most importantly. Sampling is the key step, and the reliability of IC packaging depends on their machinery in many ways.
Introduction of Failure Analysis Equipment Selection of Common Tools for Failure Analysis in Failure Analysis Laboratory

Transmission electron microscopy (TEM)
TEM is generally used to analyze the morphology, crystallographic structure and component analysis of samples. TEM can provide higher spatial resolution than SEM system, and can achieve nanometer resolution. Usually, an electron beam with energy of 60-350 keV is used.
Unlike TEM, which needs to excite secondary electrons or electron beams emitted from the surface of the sample, TEM collects those electrons that penetrate the sample. Like SEM, TEM uses an electron gun to generate an electron beam, which is focused through a lens and aperture and then becomes a smaller electron beam.
Then the sample is bombarded with this kind of electron beam. Some of the electrons can penetrate the surface of the sample and are collected by the detector located below the sample to form an image.
For crystal materials, the sample will cause the diffraction of incident electron beam, will produce local diffraction intensity variations, and can be clearly displayed on the image. For amorphous materials, when electrons penetrate these materials with different physical and chemical properties, the scattering of electrons is different, which can form a certain contrast and be observed in images.
Sampling is the most critical step for TEM analysis. The quality of sample preparation is directly related to whether TEM can effectively observe and analyze. Therefore, it is necessary for analysts to make more efforts in sample preparation. Scanning Acoustic Microscope
The reliability of IC packages depends on their mechanical integrity in many ways. Structural defects caused by poor bonding, voids, micro-cracks or interlayer peeling may not have a significant impact on electrical properties, but may cause early failure. C-mode scanning acoustic microscopy (C-SAM) is an excellent tool for non-destructive failure analysis of IC packages and can be the key. The C-SAM system has been used in reliability testing of air-tightness (ceramics) and non-air-tightness (plastics) IC packaging at the University of Maryland in the United States. It shows common production defects in plastic packaging, such as packaging crack, blade displacement, foreign impurities, porosity, passivation layer crack, interlayer peeling, cutting and fracture.
It is a failure analysis technique for sample surface analysis. Auger Electron Spectroscopy and Scanning Auger Microanalysis are two Auger Analysis technologies. These two techniques are generally used to determine the element composition of some points on the surface of the sample. Ion sputtering is generally used to measure the functional relationship between the element concentration and the depth of the sample. Auger depth can be used to determine the contamination and its location in the sample is unknown. It can also be used to analyze the composition of oxide layers, to detect Au-Al bonding strength, and so on.

The working principle of EDX or EDX is basically similar. First, an electron is emitted to bombard the surface of the sample. The impacted electrons are at a lower energy level. These lower-level space energy bands are quickly occupied by those higher-energy electrons. And this electron transition process will produce energy radiation, which will also lead to Auger electrons (Auger electrons) emission. The energy of the Auger electron emitted coincides with the energy emitted. Generally, the energy of Auger electrons is between 50 and 2400ev.
The detection system used in Auger Analysis generally measures each emitted Auger electron. Then the system makes a function according to the energy and quantity of electrons. The peaks in a function curve generally represent the corresponding elements.
FTIR Spectroscopy (Fourier Transform Infrared)
FTIR microscopy is a failure analysis technique that can provide information about chemical bonding and molecular structure of materials, whether organic or inorganic. Usually used to determine the unknown material on the surface of the sample, it is generally used as a supplement to EDX analysis.
The working principle of this system is that bonds and groups of bonds in different substances have their own characteristic frequencies. Different molecules, when exposed to infrared radiation, absorb a fixed frequency (i.e. energy) of infrared light, which is determined by the characteristics of the molecule itself. Different frequencies of infrared radiation emitted and reflected by the sample are converted into combinations of many peaks.。 Finally, the substance is determined by the spectral pattern obtained by FTIR.
Unlike SEM and EDX analysis, FTIR microscopy does not require a vacuum pump because neither oxygen nor nitrogen absorbs infrared rays. FTIR analysis can be performed on a very small number of materials, either solid, liquid or gaseous. When the FTIR spectrum does not match all the data in the library, peaks in the spectrum can be separately analyzed to determine part of the sample information. Nondestructive Testing Technology--SAM
Scanning acoustic microscope (SAM) is used in IC package scanning detection, which can detect the internal defects of the package without damaging the package.
Sink. Since in many cases the package cannot be opened for inspection, even if the original defect is opened, it is likely that the original defect has been damaged. This problem can be solved by using the transmission and reflection characteristics of ultrasonic wave. Ultrasound propagates at different speeds in different media and reflects at the interface between the two kinds of interfaces. The degree of reflection is measured by reflectivity and expressed by R. Each material also
It has its own inherent characteristics, wave impedance, expressed in Z. Wave impedance is determined by the density of the material and the propagation speed of ultrasound in the material. The relationship between them is Z-pV. When ultrasound passes through the interface between two media, its reflectivity R is determined by the impedance of the two media, R() 1 (Z/+Z)*100. When the wave propagates from medium with small impedance to medium with large impedance, that is, Z2 > z, the reflectivity R > 0. When a wave propagates from a medium with high impedance to a medium with low impedance, that is, Z2 <= ". In this way, it is easy to distinguish the normal part from the defective part and achieve the purpose of non-destructive testing. = "", r% 0. When voids, delamination, package breakdown and chip cracks occur in the package, ultrasound can not pass normally, because the medium of the voids and cracks is air, wave impedance is 0.00. So at this time, ultrasound must be propagating from medium with high impedance to medium with small impedance, r-100=">

X-ray energy spectrometer
It is mainly composed of a semiconductor detector, a multichannel analyzer or a microprocessor (Fig. 3), which is used to spread the energy spectrum of the labeled X-rays of the elements to be measured under the action of an electron beam (Fig. 4). The X-ray photons are received by a siliconized lithium-infiltrated Si (Li) detector and the electrical pulse signal is given. Because the energy of X-ray photons is different, the height of the pulse is different. After amplification and shaping, it is sent to the multi-channel pulse height analyzer. Here, according to the pulse height, that is, according to the energy size, different counting channels are entered, and then the curve of pulse number-pulse height (i.e. energy) is displayed on the X-Y recorder or picture tube. Figure 4 is an X-ray energy spectrum of a silicate iron ore containing vanadium and magnesium. The ordinate is the number of pulses, and the number of paths in the abscissa represents the height of pulses or the energy of X-ray photons. The resolution and analysis accuracy of X-ray spectrometer is not as good as that of crystal spectrometer based on wavelength, but it has no moving parts and is suitable for assembling into electron microscope. Moreover, the detector can be inserted directly near the sample. It has a high efficiency of receiving X-ray and is suitable for the detection of very weak X-ray. In addition, the X-ray spectra of all elements can be recorded or displayed simultaneously in one or two minutes. X-ray energy dispersive spectrometer (EDS) can be applied to scanning electron microscopy (SEM) to analyze the composition of the second phase on the uneven surface fracture surface, and transmission electron microscopy (TEM) to analyze the chemical composition in the range of tens of angstroms in the film sample, such as phase boundary, grain boundary or small second phase particles. Therefore, X-ray spectrometer has been widely used in electron microscopy.
A major weakness of X-ray energy spectrum analysis is that light elements with atomic number less than 11 (Na) can not be analyzed at present, because these elements have longer X-ray wavelength and are easily absorbed by beryllium windows on semiconductor detectors. Detectors without beryllium windows and thin beryllium windows are being developed to detect light elements such as carbon, nitrogen and oxygen. Relevant parameters of electron microscopy (scanning electron microscopy, transmission electron microscopy, scanning electron microscopy, TEM). Sample thinning technology
The replication technology can only replicate the surface morphology of the sample, but can not reveal the information of the internal structure of the crystal, which is affected by the replica material itself.
Due to the size limitation, the high resolution ability of the electron microscopy can not be fully developed. Although the extraction replica can analyze the structure of the extract phase, it is still a replication of the surface morphology of the matrix structure. In this case, the sample thinning technology has many characteristics, especially the metal film sample: it can give full play to the high resolution ability of electron microscopy; it can observe the internal structure and crystal defects of metals and their alloys; it can also carry out the research of the same micro-area by means of derivative imaging and electron diffraction, which can link the property information with the structure information; it can carry out dynamic observation and research. The nucleation and growth process of phase transformation at variable temperature, and the movement and interaction of crystal defects such as dislocations under gravitation. Surface Reproduction Technology

The so-called replication technology is to replicate the surface of the metallographic sample by etching the micro-structure relief on a very thin film, and then the replication film (called "replica") is put into the transmission electron microscopy to observe and analyze, so as to make it possible for the transmission electron microscopy to be used to display the micro-structure of metal materials. The material used to prepare the replica must satisfy the following characteristics: it must be "unstructured" (or "amorphous"). That is to say, in order not to interfere with the observation of the replicated surface morphology, it is required that the replica material do not display any structural details of itself even when it is imaged at a high (for example, 100,000 times). The electron beam must be transparent enough (the atomic number of matter is low); it must have enough strength and stiffness to avoid breaking or distortion in the process of replication; it must have good conductivity and resistance to electron beam bombardment; it is better to have a material with smaller molecular size - - high resolution. Relevant Parameters of Electron Microscope (Scanning Electron Microscope, Transmission Electron Microscope) (II). Auger Electron
If the energy released during the transition of the electron level in the inner layer of an atom is not released in the form of X-ray, but is used to knock out another electron outside the nucleus and change it from atom to secondary electron, the secondary electron is called Auger electron. Since each atom has its own specific shell energy, their Auger electron energy also has its own eigenvalue, which is in the range of 50-1500eV. Auger electrons are emitted from a few atomic layers on the surface of the sample, which indicates that Auger electronic signals are suitable for surface chemical analysis. · Characteristic X-ray
An electromagnetic wave radiation with characteristic energy and wavelength released directly by the inner electrons of a characteristic X-ray atom in the process of energy level transition after excitation. X-rays are usually emitted at 500-5 m m depth of the specimen. · secondary electrons
Secondary electrons are extranuclear electrons bombarded by back-incident electrons. Because the binding energy between the nucleus and the outer valence electrons is very small, when the external electrons of the atom obtain more energy than the corresponding binding energy from the incident electrons, they can be separated from the atom and become free electrons. If the scattering occurs near the surface of the sample, the free electrons whose energy is greater than the work of the material can escape from the surface of the sample and become the free electrons in vacuum, i.e. secondary electrons. Secondary electrons come from the 5-10 nm region of the surface, and the energy is 0-50 eV. It is very sensitive to the surface state of the sample and can effectively display the micro-morphology of the sample surface. Since it originates from the surface of the sample and the incident electrons have not been reflected many times, the area of secondary electrons generated is not much different from that of incident electrons, so the resolution of secondary electrons is high, generally up to 5-10 nm. The resolution of scanning electron microscopy is generally secondary electron resolution. The amount of secondary electrons varies little with the atomic number, mainly depending on the surface morphology.