Development of accurate linewidth measurement techniques for in-process wafers

Author(s):  
Robert. L. Van Asselt ◽  
Heinrich Becker

Measurements of the device geometries on “in-process” wafers present some interesting challenges. Sample coating is not possible and the measurement probe must not damage the devices. The Scanning Electron Microscope (SEM) is the standard tool for submicrometer measurements. However, operating at the low electron beam accelerating voltage required to avoid damage to integrated circuits introduces problems in resolution. Also, the measurement accuracy may be limited by the effects of surface charging and topography. Further, SEM linewidth standards do not exist at the present time. Optical measurements are attractive because, in general, they display greater precision, are typically less expensive to implement and have a higher throughput. However, diffraction effects associated with the complex three-dimensional geometries of integrated circuit structures make accurate measurements very difficult. The "blur" regions that occur in the optical image at each edge must be interpreted to predict the actual location of the structure edges.

Author(s):  
S. Khadpe ◽  
R. Faryniak

The Scanning Electron Microscope (SEM) is an important tool in Thick Film Hybrid Microcircuits Manufacturing because of its large depth of focus and three dimensional capability. This paper discusses some of the important areas in which the SEM is used to monitor process control and component failure modes during the various stages of manufacture of a typical hybrid microcircuit.Figure 1 shows a thick film hybrid microcircuit used in a Motorola Paging Receiver. The circuit consists of thick film resistors and conductors screened and fired on a ceramic (aluminum oxide) substrate. Two integrated circuit dice are bonded to the conductors by means of conductive epoxy and electrical connections from each integrated circuit to the substrate are made by ultrasonically bonding 1 mil aluminum wires from the die pads to appropriate conductor pads on the substrate. In addition to the integrated circuits and the resistors, the circuit includes seven chip capacitors soldered onto the substrate. Some of the important considerations involved in the selection and reliability aspects of the hybrid circuit components are: (a) the quality of the substrate; (b) the surface structure of the thick film conductors; (c) the metallization characteristics of the integrated circuit; and (d) the quality of the wire bond interconnections.


Author(s):  
Halit Dogan ◽  
Md Mahbub Alam ◽  
Navid Asadizanjani ◽  
Sina Shahbazmohamadi ◽  
Domenic Forte ◽  
...  

Abstract X-ray tomography is a promising technique that can provide micron level, internal structure, and three dimensional (3D) information of an integrated circuit (IC) component without the need for serial sectioning or decapsulation. This is especially useful for counterfeit IC detection as demonstrated by recent work. Although the components remain physically intact during tomography, the effect of radiation on the electrical functionality is not yet fully investigated. In this paper we analyze the impact of X-ray tomography on the reliability of ICs with different fabrication technologies. We perform a 3D imaging using an advanced X-ray machine on Intel flash memories, Macronix flash memories, Xilinx Spartan 3 and Spartan 6 FPGAs. Electrical functionalities are then tested in a systematic procedure after each round of tomography to estimate the impact of X-ray on Flash erase time, read margin, and program operation, and the frequencies of ring oscillators in the FPGAs. A major finding is that erase times for flash memories of older technology are significantly degraded when exposed to tomography, eventually resulting in failure. However, the flash and Xilinx FPGAs of newer technologies seem less sensitive to tomography, as only minor degradations are observed. Further, we did not identify permanent failures for any chips in the time needed to perform tomography for counterfeit detection (approximately 2 hours).


Author(s):  
Ashok Raman ◽  
Marek Turowski ◽  
Monte Mar

This paper presents full-chip scale detailed thermal simulations of three-dimensional (3D) integrated circuit (IC) stacks. The inter-layer dielectric (ILD) and inter-metal dielectric (IMD) materials inside 3D IC stacks may cause extensive localized heating. The influence of multiple layers of dielectrics on heat trapping inside the 3D stack is analyzed. Different methods to minimize such localized heating are studied. It is shown that the use of thermal vias is very effective in heat dissipation from the hot spots. Comparisons are made between several 3D IC configurations to verify these conclusions.


2015 ◽  
Vol 137 (4) ◽  
Author(s):  
Soud Farhan Choudhury ◽  
Leila Ladani

Currently, intermetallics (IMCs) in the solder joint are getting much attention due to their higher volume fraction in the smaller thickness interconnects. They possess different mechanical properties compared to bulk solder. Large volume fraction of IMCs may affect the mechanical behavior, thermomechanical and mechanical fatigue life and reliability of the solder interconnects due to very brittle nature compared to solder material. The question that this study is seeking to answer is how degrading IMCs are to the thermomechanical reliability of the microbumps used in three-dimensional (3D) integrated circuits (ICs) where the microsolder bumps have only a few microns of bond thicknesses. Several factors such as “squeezed out” solder geometry and IMC thickness are studied through a numerical experiment. Fatigue life is calculated using Coffin–Manson model. Results show that, though undesirable because of high likelihood of creating short circuits, squeezed out solder accumulates less inelastic strains under thermomechanical cyclic load and has higher fatigue life. The results show that with the increase of IMCs thickness in each model, the inelastic strains accumulation per cycle increases, thus decreasing the fatigue life. The drop in fatigue life tends to follow an exponential decay path. On the other hand, it was observed that plastic strain range per cycle tends to develop rapidly in Cu region with the increase in IMC thickness which calls for a consideration of Cu fatigue life more closely when the microbump contains a higher volume fraction of the IMCs. Overall, by analyzing the results, it is obvious that the presence of IMCs must be considered for microsolder bump with smaller bond thickness in fatigue life prediction model to generate more reasonable and correct results.


2020 ◽  
Vol 10 (3) ◽  
pp. 748
Author(s):  
Dipesh Kapoor ◽  
Cher Ming Tan ◽  
Vivek Sangwan

Advancements in the functionalities and operating frequencies of integrated circuits (IC) have led to the necessity of measuring their electromagnetic Interference (EMI). Three-dimensional integrated circuit (3D-IC) represents the current advancements for multi-functionalities, high speed, high performance, and low-power IC technology. While the thermal challenges of 3D-IC have been studied extensively, the influence of EMI among the stacked dies has not been investigated. With the decreasing spacing between the stacked dies, this EMI can become more severe. This work demonstrates the potential of EMI within a 3D-IC numerically, and determines the minimum distance between stack dies to reduce the impact of EMI from one another before they are fabricated. The limitations of using near field measurement for the EMI study in stacked dies 3D-IC are also illustrated.


2006 ◽  
Vol 129 (3) ◽  
pp. 664-671 ◽  
Author(s):  
Peter Weigand ◽  
Wolfgang Meier ◽  
Xuru Duan ◽  
Manfred Aigner

Nonintrusive laser-based and optical measurements were performed in a gas turbine model combustor with a lean premixed swirl-stabilized CH4-air flame at atmospheric pressure. The main objective was to gain spatially and temporally resolved experimental data to enable the validation of numerical CFD results of oscillating flames. The investigated flame was operated at 25 kW and ϕ=0.70, and exhibited self-excited oscillations of more than 135 dB at ≈300Hz. The applied measurement techniques were three-dimensional (3D) laser doppler velocimetry (LDV) for velocity measurements, OH* chemiluminescence yielding information about the heat release and pointwise laser Raman scattering for the determination of joint probability density functions (PDFs) of the major species concentrations, temperature, and mixture fraction. Each of these techniques was applied with phase resolution with respect to the periodic fluctuation of the pressure in the combustion chamber that was measured with a microphone probe. The measurements finally revealed that the mixing of fuel and air in this technical premixing system was strongly affected by the pressure fluctuations leading to changes in equivalence ratio during an oscillation cycle that, in turn, induced the pressure fluctuations.


Nanomaterials ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 2488
Author(s):  
Siqi Tang ◽  
Jiang Yan ◽  
Jing Zhang ◽  
Shuhua Wei ◽  
Qingzhu Zhang ◽  
...  

In this paper, the poly-Si nanowire (NW) field-effect transistor (FET) sensor arrays were fabricated by adopting low-temperature annealing (600 °C/30 s) and feasible spacer image transfer (SIT) processes for future monolithic three-dimensional integrated circuits (3D-ICs) applications. Compared with other fabrication methods of poly-Si NW sensors, the SIT process exhibits the characteristics of highly uniform poly-Si NW arrays with well-controlled morphology (about 25 nm in width and 35 nm in length). Conventional metal silicide and implantation techniques were introduced to reduce the parasitic resistance of source and drain (SD) and improve the conductivity. Therefore, the obtained sensors exhibit >106 switching ratios and 965 mV/dec subthreshold swing (SS), which exhibits similar results compared with that of SOI Si NW sensors. However, the poly-Si NW FET sensors show the Vth shift as high as about 178 ± 1 mV/pH, which is five times larger than that of the SOI Si NW sensors. The fabricated poly-Si NW sensors with 600 °C/30 s processing temperature and good device performance provide feasibility for future monolithic three-dimensional integrated circuit (3D-IC) applications.


Author(s):  
Leila Choobineh ◽  
Nick Vo ◽  
Trent Uehling ◽  
Ankur Jain

Accurate measurement of the thermal performance of vertically-stacked three-dimensional integrated circuits (3D ICs) is critical for optimal design and performance. Experimental measurements also help validate thermal models for predicting the temperature field in a 3D IC. This paper presents results from thermal measurements on a two-die 3D IC. The experimental setup and procedure is described. Transient and steady-state measurements are made while heating the top die or the bottom die. Results indicate that passage of electrical current through the heaters in top/bottom die induces a measureable temperature rise. There appears to be a unique asymmetry in thermal performance between the top die and the bottom die. The top die is found to heat up faster and more than the bottom die. Results presented in this paper are expected to play a key role in validation of simulation-based and analytical thermal models for 3D ICs, and lead to a better fundamental understanding of heat transport in stacked systems. This is expected to lead to effective thermal design and characterization tools for 3D ICs.


2016 ◽  
Vol 138 (1) ◽  
Author(s):  
Thomas Brunschwiler ◽  
Arvind Sridhar ◽  
Chin Lee Ong ◽  
Gerd Schlottig

An overview of the thermal management landscape with focus on heat dissipation from three-dimensional (3D) chip stacks is provided in this study. Evolutionary and revolutionary topologies, such as single-side, dual-side, and finally, volumetric heat removal, are benchmarked with respect to a high-performance three-tier chip stack with an aggregate power dissipation of 672 W. The thermal budget of 50 K can be maintained by three topologies, namely: (1) dual-side cooling, implemented by a thermally active interposer, (2) interlayer cooling with four-port fluid delivery and drainage at 100 kPa pressure drop, and (3) a hybrid approach combining interlayer with embedded back-side cooling. Of all the heat-removal concepts, interlayer cooling is the only approach that scales with the number of dies in the chip stack and hence enables extreme 3D integration. However, the required size of the microchannels competes with the requirement of low through-silicon-via (TSV) heights and pitches. A scaling study was performed to derive the TSV pitch that is compatible with cooling channels to dissipate 150 W/cm2 per tier. An active integrated circuit (IC) area of 4 cm2 was considered, which had to be implemented on the varying tier count in the stack. A cuboid form factor of 2 mm × 4 mm × 2.55 mm results from a die count of 50. The resulting microchannels of 2 mm length allow small hydraulic diameters and thus a very high TSV density of 1837 1/mm2. The accumulated heat flux and the volumetric power dissipation are as high as 7.5 kW/cm2 and 29 kW/cm3, respectively.


Author(s):  
D. A. Serov ◽  
K. V. Pershina ◽  
I. V. Burdina

This article describes the application of optical nanocomponents for their further use in computer and information systems. it was revealed It was found on the basis of the analysis that the improvement of existing nanocomponents will allow to realize their full potential, as well as to find the use of nanoantennas in the field of creating communication lines on device boards as devices for receiving and transmitting data. Nanoantennas are promising devices that are already successfully used in modern microscopy devices. However, recently, optical antennas have begun to be applied in devices used in other areas of human life. As a result, the use of this technology can lead to an increase in the speed and volume of data transfer between the components of the integrated circuit. This, in turn, will increase the quality and speed of calculations in complex equations. A modeling technology has been proposed, and calculations of the necessary geometric parameters have been made, which will be suitable for the goals set by this work. On the basis of the proposed technology, four models that meet the required parameters have been developed. Calculations of the created three-dimensional models of nanoantennas have been performed. As a result of the study, a model has been identified that has the most balanced parameters suitable for its further use as the main device for receiving and transmitting data on three-dimensional integrated circuits.


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