1 optical microscope analysis technology
Optical microscope analysis techniques are mainly stereomicroscope and metallurgical microscope.
Stereomicroscope magnification is small, but the depth of field; Metallurgical microscope magnification, from tens of times to more than a thousand times, but the depth of field is small. The combination of these two microscopes allows the appearance of the device to be observed, along with the surface shape, distribution, size, texture, structure and stress of the failure site. Such as used to observe the chip burned and breakdown phenomenon, wire bonding, substrate cracking, contamination, scratches, oxide defects, corrosion of the metal layer. Microscopes can also be equipped with assistive devices to provide bright field, dark field, differential interference phase contrast and polarization observation means to meet the various needs.
2 infrared analysis technology
The structure of an infrared microscope is similar to that of a metallographic microscope. But it uses near infrared (wavelength of 0175 ~ 3 microns) light source, and the use of infrared image tube imaging. Due to germanium, silicon and other semiconductor materials and thin metal layer is transparent to infrared radiation. Use it, do not cut the device chip can observe the internal chip defects and welding conditions. It is also particularly suitable for failure analysis of plastic-encapsulated semiconductor devices.
Infrared microscopy is the use of infrared microscopy of micro-electronic devices for the small area of high-precision non-contact temperature measurement method. Device performance and failure will be reflected through the thermal effects. Improper device design, material defects, process errors, etc., can cause localized temperature increases. Hot spots may be as small as microns, so the temperature must be for small areas. In order not to affect the operation of the device and electrical characteristics, the measurement must be non-contact. Identifying hot spots and measuring the temperature with high precision by non-contact methods are of great significance to product design, process control, failure analysis and reliability testing.
Infrared camera is non-contact temperature measurement technology, which can measure the surface temperature of each point, gives the temperature distribution of the sample surface.
Infrared thermal imaging camera with vibration, mirrors and other optical systems for high-speed scanning of the sample will be from the surface of the specimen at each point of the thermal radiation converged to the detector, into an electrical signal, and then the display to form a black and white or color image so that Used to analyze the surface temperature of each point.
3 Acoustic microscopy analysis
Ultrasound can be spread in homogeneous materials such as metals, ceramics and plastics. Ultrasonic inspection of the material surface and the surface of the lower edge of the rupture, multi-layer structure integrity can detect more macro defects. Ultrasound is a very effective means of detecting defects and performing failure analysis. Combining ultrasonic testing with advanced optical, mechanical, and electrical technologies, Acoustic Microanalysis has also been developed that allows the observation of internal samples not visible to optical microscopes and provides a high degree of contrast unobtainable by X-ray fluoroscopy Images can be applied to non-destructive analysis.
4 LCD hot spot detection technology
As mentioned earlier, the semiconductor device failure analysis, hot spot detection is an effective means.
Liquid crystal is a liquid, but when the temperature is below the phase transition temperature, it becomes crystalline.
Crystal will show anisotropy. When it is heated, the temperature is higher than the phase transition temperature, it will become isotropic liquid. Using this feature, you can observe the phase transition point of liquid crystal in the orthogonal polarized light to find hot spots.
LCD hot spot detection equipment consists of a polarizing microscope, adjustable temperature sample stage and the sample of the electrical bias control circuit.
LCD hot spot detection technology can be used to check for pin holes and hot spots and other defects. If there is pinhole in the oxide layer, the metal layer above it and the underlying semiconductor may be short-circuited, causing the electrical characteristics to degrade or even fail. The liquid crystal is coated on the surface of the tested die, and then the sample is placed on a heating stage. If there is a pinhole in the die oxide layer, leakage current will occur and heat will be generated, so that the temperature at this point will increase. Using orthogonal polarized light Under an optical microscope, observing the difference between the hot spot and the surrounding color, the hot spot location on the device can be determined.
Due to small power consumption, this method has high sensitivity and high spatial resolution.
5 optical radiation microscopy analysis technology
Semiconductor materials in the electric field excitation, the carrier will jump in the energy level and emit photons. Light radiation in semiconductor devices and integrated circuits can be divided into three categories: one is the injection of a minority son into the composite radiation of a pn junction, ie a non-equilibrium minority carrier is injected into the potential barrier and recombines with the majority carriers to emit photons. Second, the electric field accelerates the carrier light, that is, the high-speed moving carriers generated by the strong electric field collide with the atoms on the lattice to make it ionize and emit light. Third, the media glow. In a strong electric field tunneling current through silicon dioxide and silicon nitride and other dielectric film, there will be photon emission.
Optical radiation microscopy with low light detection technology, the photon detection sensitivity increased by 6 orders of magnitude, combined with digital image technology to improve the signal-to-noise ratio.
After the 1990s, the function of spectral analysis of detected optical radiation was added so that the type and nature of optical radiation could be determined.
To do light-field microscopy, a real-time image of the sample is partially exposed to an external light source and then biased locally to detect the light radiation from the sample in an opaque, shielded enclosure.
In semiconductor devices, various types of defects and damages generate electric leakage under the action of a certain strength of an electric field, and generate optical radiation accompanying the carrier leap. In this way, the positioning of the light-emitting part may be the positioning of the failed part. Currently, there are leaky junctions, contact spikes, oxide defects, gate pin holes, electrostatic discharge damage, latch-up effects, hot carriers, saturated transistors, and switching state transistors that can be detected by optical radiation microscopy and many more.
6 micro-analysis technology
Microanalysis is a technique for in-depth analysis of electronic components. The failure of the components is directly related to the chemical composition of the materials used, the structure of the device and the morphology of the micro-regions. Failure is also related to the fluctuation and accuracy of process control, the stability of the material and the physical and chemical effects of various materials. In order to further understand and study the causes, mechanisms and modes of failure, in addition to using the above technologies, we must also clarify the relevant micro-area situation and obtain detailed information.
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