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1.
Four groups of samples deposited at different temperatures, TD, have been characterized by means of the SARF (Spectral Analysis of Resistance Fluctuations) technique. For each temperature, lines with the same length (800 μm) and two different widths (1 μm and 2 μm) were available. An accurate TEM (Transmission Electron Microscopy) analysis has been carried out with the aim of investigating the dependence of the microstructure on TD. While 1-μm-wide lines showed a quasi-bamboo structure, regardless of TD, 2-μm-wide lines appeared constituted by grains whose size was smaller than the stripe width. In this case, the grain size distribution was dependent on TD. A new microstructural parameter has been introduced to which electromigration noise seems to be very sensitive: the percentage of grains of the metal film whose size is smaller than the stripe width. The correlation observed among noise parameters, microstructural characteristics of the lines and, in the case in which they were available, lifetime data, has confirmed the potentiality of the SARF technique as a diagnostic tool.  相似文献   

2.
发光二极管(LED)是恒流工作的器件,并且随着LED功率的不断增加,散热问题变得越加突出,温度控制十分必要。当LED功率比较小时,可以用温度传感器来检测它的温度;而当LED做到晶圆级发光二极管(WLED),功率达到千瓦,传统的驱动方式、散热方式以及温度的控制已不再适用。晶圆级发光二极管有多条支路,采用多路恒流以保证每条支路的电流相同。对于温度的控制,将晶圆级发光二极管平均结温变化量的测量转换为对冷却液温度的变化量的测量,进而通过与冷却液温度变化量的关系进行控制。本设计解决了晶圆级发光二极管因工艺问题导致的“抢电流”的问题,并将复杂的温度控制变得简单化,而且节省成本。  相似文献   

3.
Highlights the major trends and issues affecting monolithic wafer-scale circuits and hybrid wafer-scale circuits, i.e. pretested chips mounted on silicon wafer circuit boards. An extensive set of references is provided to avoid repeating detailed discussions available in the cited literature. Instead, a broad overview of the objectives and motivations of the considerable work on wafer-level system components is provided. It is emphasized that wafer-scale integration provides a foundation on which future systems, perhaps including advanced semiconductor technologies for high-performance components, can achieve evolutionary increases in performance and decreases in system size.<>  相似文献   

4.
Wafer Level Reliability test techniques can be used to provide fast feedback process control information regarding the reliability of the product of a semiconductor process. The purpose of wafer level reliability (WLR) tests is the measurement of variation in the materials comprising the semiconductor device. They are not intended as modeling tools for the quantification of the effect of stress on these materials. As such, WLR tests must provide a repeatable stress, independent of normal process variation. The results of these tests will be a measurement of the “rate of degradation” of the basic circuit elements caused by a standard stress.  相似文献   

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In this paper a novel wide-band propagation channel measurement system with high dynamic range and sensitivity is introduced. The system enables the user to characterize signal propagation through a medium over a very wide frequency band with fine spectral resolution (as low as 3 Hz) by measuring the attenuation and phase characteristics of the medium. This system also allows for the study of temporal, spectral and spatial decorrelation. The high fidelity data gathered with this system can also be utilized to develop empirical models or used as a validation tool for physics based propagation models which simulate the behavior of radio waves in different environments such as forests, urban areas or indoor environments. The mobility and flexibility of the system allows for site specific measurements in various propagation scenarios.  相似文献   

7.
Analysis and design of interconnects in high speed integrated circuits and systems involves models in the form of multiconductor transmission lines. The fundamental parameters of those models are matrices of capacitance, (C), inductance, (L), resistance, (R), and conductance (G). We present a methodology for measurement of entries in capacitance matrix. The entries of capacitance matrices can be calculated using numerical solvers of electrostatic fields established under the assumption of suitable biasing of interconnect structures. Numerical calculations of complete field equations are very complex and expensive in terms of computer time, therefore several approximations are made in constructing interconnect dedicated software packages available on the market. Because of these approximations it is necessary to validate the calculations via measurements. Calculation of the off-diagonal entries of capacitance matrix from measurements of "two-terminal" capacitances is strongly corrupted by the measuring errors. The method involves direct capacitance measurement in multi-conductor structures and provides analysis of accuracy.  相似文献   

8.
In this paper, a scaled measurement system designed for wireless channel characterization is proposed and discussed, and experimental results are reported. The system consists of a vector network analyzer, miniaturized W-band transmitter and receiver probes, scaled buildings, and a precise computer-controlled positioner. The scaled propagation measurement system is designed to operate coherently at the 90.8-92.8-GHz band, and it provides a dynamic range of 85 dB. As the measurement wavelength in this system (/spl cong/3 mm) is approximately two orders of magnitude smaller than the actual wavelength in most commercial and military wireless systems, a typical dimension of the propagation environment can be smaller than the actual environment proportionally. Hence, propagation measurements can be done very efficiently under laboratory conditions using a scaled model of a city block. This system is intended for verifying the results of wave-propagation prediction software. It can also be used to investigate scattering models for different types of buildings and complex objects, data collection for wireless communication, and many other studies such as diversity methods (frequency and polarization).  相似文献   

9.
Some of the problems connected with the characterization of electromigration by means of noise measurements are discussed in this paper. Some specific criticisms moved in the past toward the interpretation of the experimental data are also addressed. In particular, the question of the interpretation of the 1/ƒ2 noise component is discussed. Finally, a set of rules are given which should be followed, both in the choice of the instrumentation and in performing the measurements, in order to obtain meaningful and reliable results.  相似文献   

10.
Programming of EPROM microcontrollers normally takes place at the backend test operations. However, programming is best done at the wafer level sort testing operation as it is cost effective and entails the least handling. However, there are certain risks with the latter. EPROM memory retention is a quality and reliability concern if there is any EPROM memory charge loss due to heat treatments induced during assembly processing. This paper deals with the theories and evaluations to support programming at the wafer sort operation  相似文献   

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《Microelectronics Reliability》2015,55(11):2276-2283
Reliability of embedded electronic products is a challenging issue regarding ElectroStatic Discharge (ESD) events into real live applications. This is strongly related to the increased number of embedded systems and to technologies shrinking that result in less robust chips. To ensure the safety of electronic systems, the ESD events have to be taken into account at first design phase. But equipment manufacturers are facing the dilemma that no information is provided by the semiconductor manufacturers. At the same time Integrated Circuit (IC) designers have to take into account the final application environment to build the ESD protection strategy. Depending on the external components (external means around the chip) the on-chip current path could change. Understanding how the system environment impacts the current path within the chip is needed. This paper deals with on-chip oscilloscope developed for in-situ measurement of real ESD event in 65 nm CMOS technology. The measurement bandwidth of the embedded sampler is 100 GHz, and 20 GHz for the probes. Thanks to this technique, impact of the system on the current path of the on-chip ESD strategy will be observed. Some measurement results during an ESD stress on an I/O structure will be presented and analyzed showing that PCB trace and package induce the creation of new current paths.  相似文献   

13.
The advent of chip scale packages (CSPs) within the semiconductor community has led to the development of wafer scale assembly (WSA) or wafer level packaging (WLP) manufacturing in order to raise assembly efficiencies and lower operating costs. Texas Instruments (TI) has developed a unique WLP process for forming flip-chip, ball grid array packages. The die inputs and outputs of the TI CSP are connected through solder bumps to a polyimide film interposer. Solder balls on the other side of the interposer complete the electrical connection to a customer’s printed circuit board. A wafer-sized array of interposers designed to match the pattern of dies on a wafer is aligned and reflowed to a bumped wafer. The TI WLP process is completed by singulating the CSPs from the wafer using standard wafer saw equipment.Attachment of the interposer to the die as well as applying the die and board level solder bumps are carried out in wafer form using a new bumping technology called Tacky Dots™. Tacky Dots uses an array of sticky dots formed in a photosensitive coating laminated to a polyimide film for transferring and attaching solder spheres to semiconductor substrates. A populated film containing one solder sphere per Tacky Dot is positioned over the wafer or interposer and lowered until the spheres contact the pads. A reflow process transfers the spheres from the film to the wafer or interposer and the film is removed once the spheres have frozen.This paper illustrates the process steps and custom equipment developed for forming the TI CSP. The strategic use of finite element modeling for optimizing the design of the package is outlined. The paper concludes by summarizing the current package level reliability results.  相似文献   

14.
The high sensitivity, which can be obtained by means of noise measurements, is especially useful for the characterization of the early stages of the electromigration phenomenon. In addition, with the noise being strictly dependent on the sample microstructure, it is obvious to expect that it can be used for monitoring the different stages of the degradation process. In this paper, the results obtained by performing noise measurements during lifetime tests are presented, with the aim of investigating the evolution of the electromigration noise during the entire life of the sample. Conventional Median Time to Failure (MTF) tests have been performed on samples belonging to the same set. One of the aims of this work is to investigate the possibility of establishing a new failure criterion based on noise measurement capable of providing, in a shorter time, the same type of information normally obtained from MTF tests.  相似文献   

15.
A back-to-back measurement method for characterizing phased-array antennas is described. The method yields the complex active impedance of an antenna in a large phased array at any desired frequency and scan angle without the need of a feed network to excite the antenna under test. This avoids the cost and de-embedding procedure associated with the feed network. Measurements are performed by using two different transmission networks to connect identical arrays in a back-to-back configuration. The new method is particularly well suited to printed antennas and is illustrated by using tapered-slot antennas. Back-to-back measurements in waveguide simulators compare well to traditional waveguide simulator measurements and measurements in an anechoic chamber compare well to results from computer codes based on the full-wave method of moments  相似文献   

16.
10-9 atm cc/s are possible, meeting the demands of MIL-STD-883E.  相似文献   

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18.
In flip chip package applications, bumped dies are flip-chip assembled to substrate metal pads creating joints that serve electrically and mechanically. Resulting solder joint profiles are defined by the solder bump volume, the under bump metallurgy (LTBM) area, and the substrate metal pad size and shape. Solder bump height and diameter was predicted by the geometrical truncated sphere model and surface evolver model at the wafer level, using the known solder volume deposited by stencil printing method. The surface evolver model was used to predict the assembled solder joint height, gap height, collapse height, and maximum bump diameter of flip chip assemblies. In turn, substrate pads were fine-tuned to achieve required gap heights. Collapse heights provided the means to develop assembly tolerances and relative risk of bridging was determined from knowledge of resulting bump diameters. Through validated design of the stencil printing technology and prediction of realistic bump and assembly solder geometries, the results are improved processes and die level design and assembly. Optimized design parameters are incorporated and accurately represented in simulation and experimentally validated with assemblies  相似文献   

19.
Several wafer level chip scale package (WLCSP) technologies have been developed which generate fully packaged and tested chips on the wafer prior to dicing. Many of these technologies are based on simple peripheral pad redistribution technology followed by attachment of 0.3-0.5 mm solder balls. The larger standoff generated by these solder balls result in better reliability for the WLCSP's when underfill is not used than for equivalent flip chip parts. RambusTM RDRAM and integrated passives are two applications that should see wide acceptance of WLCSP packages  相似文献   

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