Effect of Polymer Liners in Different Via Shapes: Impact on Crosstalk Induced Delay

2021 ◽  
Author(s):  
Maya Chandrakar ◽  
Manoj Kumar Majumder
Keyword(s):  
Integrated Circuit ◽  
Coefficient Of Thermal Expansion ◽  
Electrical Network ◽  
Worst Case ◽  
Liner Material ◽  
Low Dielectric ◽  
Aspect Ratios ◽  
Cte Mismatch ◽  
Metal Liner ◽  
The Impact

Abstract The performance of a through silicon via (TSV) based 3D integrated circuit technology is primarily dependent on the choice of an appropriate liner material. The most commonly used liner material SiO2 is undergoing considerable reliability challenges such as coefficient of thermal expansion (CTE) mismatch, scallop formation, and interfacial delamination related problems. Therefore, TSVs employed with a polymer liner have achieved significant attention in recent years due to their low dielectric constant and excellent step coverage along the via surface that can effectively reduce thermal stress and crosstalk induced delay. This paper presents a comprehensive and accurate RLGC model for different via shapes considering the impact of various liner materials on the crosstalk induced delay. Considering an accurate via geometry and material properties at 32 nm and 45 nm technology, the proposed equivalent RLGC parameters include the cumulative effects of TSV metal, liner, bump, and the silicon substrate. The aforementioned parameters are used to model a novel T-type equivalent electrical network of cylindrical, tapered, and coaxial TSVs considering a coupled driver-via-load (DVL) setup. The proposed equivalent models of different via shapes are used to demonstrate the worst-case crosstalk induced delay in TSVs under the influence of various liner materials. Considering a tapered TSV, a significant improvement in crosstalk induced delay at 32 nm w.r.t. 45 nm technology is observed as 53.5%, 33.76%, and 19.12% at aspect ratios of 2.4, 3, and 4, respectively for the BCB liner.

The Effects of the Mechanical Properties of the Confinement Material on Electromigration in Metallic Interconnects

2000 ◽  
Vol 612 ◽  
Author(s):  
Stefan P. Hau-Riege ◽  
Carl V. Thompson
Keyword(s):  
Mechanical Properties ◽  
Integrated Circuits ◽  
Effective Elastic Modulus ◽  
Low Dielectric Constant ◽  
Stress Evolution ◽  
Liner Material ◽  
Low Dielectric ◽  
Aspect Ratios ◽  
Induced Stress ◽  
The Standard Model

AbstractNew low-dielectric-constant inter-level dielectrics are being investigated as alternatives to SiO2 for future integrated circuits. In general, these materials have very different mechanical properties from SiO2. In the standard model, electromigration-induced stress evolution caused by changes in the number of available lattice sites in interconnects is described by an effective elastic modulus, B. Finite element calculations have been carried out to obtain B as a function of differences in the modulus, E, of interlevel dielectrics, for several stress-free homogeneous dilational strain configurations, for several line aspect ratios, and for different metallization schemes. In contradiction to earlier models, we find that for Cu-based metallization schemes with liners, a decrease in E by nearly two orders of magnitude has a relatively small effect on B, changing it by less than a factor of 2. However, B, and therefore the reliability of Cu interconnects can be strongly dependent on the modulus and thickness of the liner material.

The Effects of the Mechanical Properties of the Confinement Material on Electromigration in Metallic Interconnects

2000 ◽  
Vol 15 (8) ◽  
pp. 1797-1802 ◽  
Author(s):  
Stefan P. Hau-Riege ◽  
Carl V. Thompson
Keyword(s):  
Mechanical Properties ◽  
Integrated Circuits ◽  
Effective Elastic Modulus ◽  
Low Dielectric Constant ◽  
Stress Evolution ◽  
Liner Material ◽  
Low Dielectric ◽  
Aspect Ratios ◽  
Induced Stress ◽  
The Standard Model

New low-dielectric-constant interlevel dielectrics are being investigated as alternatives to SiO2 for future integrated circuits. In general, these materials have very different mechanical properties from SiO2. In the standard model, electromigration-induced stress evolution caused by changes in the number of available lattice sites in interconnects is described by an effective elastic modulus, B. Finite element calculations were carried out to obtain B as a function of differences in the modulus, E, of interlevel dielectrics, for several stress-free homogeneous dilational strain configurations, for several line aspect ratios, and for different metallization schemes. In contradiction to earlier models, we found that for Cu-based metallization schemes with liners, a decrease in E by nearly two orders of magnitude has a relatively small effect on B, changing it by less than a factor of 2. However, B, and therefore the reliability of Cu interconnects, can be strongly dependent on the modulus and thickness of the liner material.

Glass Carrier Wafers for the Si Thinning Process for Stack IC Applications

2013 ◽  
Vol 2013 (DPC) ◽  
pp. 000989-001008
Author(s):  
Aric Shorey ◽  
Bor-Kai Wang ◽  
Joe Canale ◽  
Windsor Thomas
Keyword(s):  
High Precision ◽  
Integrated Circuit ◽  
Performance Optimization ◽  
Coefficient Of Thermal Expansion ◽  
High Volume ◽  
Target Thickness ◽  
Thickness Variation ◽  
Forming Process ◽  
Thinning Operations ◽  
The Impact

Glass carriers have proven to provide a solution for carriers during wafer thinning operations for 3D-IC (Three-Dimensional Integrated Circuit). The attributes of the glass carrier, such as total thickness variation (TTV), flatness and properties such as coefficient of thermal expansion (CTE), are extremely important in their functional performance. Optimization of Corning's fusion forming process gives a platform that is very well suited to generate high precision glass carriers. This process provides glass at target thickness (no grind/polish required) with a pristine surface, extremely tight TTV, low warp/bow, and thickness tolerance over large volumes of material. Given that this material is formed in sheets as large as three meters in size, there is tremendous flexibility in the size of the wafers; as well as ability to scale to high volume manufacturing in a cost effective way. Furthermore, the ability to alter glass composition provides the opportunity to optimize material properties, such as CTE. This is important to accommodate the needs of various device structures which require thinning. Non-uniformities (TTV, flatness) in the carrier directly impact the accuracy of the thinned wafer TTV. As important as the low TTV and warp/bow provided by Corning's optimized fusion process, is the method in which these attributes are characterized. Corning ® Tropel ® has developed a novel distance measuring interferometer based on a frequency stepping laser that is well-suited to characterize the flatness and TTV of glass wafers. The work presented here will highlight the importance of high precision carriers and metrology techniques used to characterize and qualify these materials. The impact these have on the TTV of a bonded stack is just as critical. The ability to leverage all of these tools to provide bonded stacks with extremely low TTV and highly uniform silicon wafers after thinning operations will be demonstrated.

Effect of Temperature Cycling and High Temperature Aging on the Elastic Properties and Failure Modes of Thermal Interface Materials

2015 ◽  
Author(s):  
Taryn J. Davis ◽  
Tuhin Sinha ◽  
Ken Marston ◽  
Sushumna Iruvanti
Keyword(s):  
Thermal Performance ◽  
Failure Modes ◽  
Coefficient Of Thermal Expansion ◽  
Temperature Cycling ◽  
Thermal Interface Materials ◽  
Thermal Interface ◽  
Main Challenge ◽  
Cte Mismatch ◽  
The Impact ◽  
Interface Materials

Highly filled thermally conductive silicone gels are routinely used as first level thermal interface materials (TIMs) between the die and lid, in flip-chip organic packages. The main challenge for these TIMs is overcoming the Coefficient of Thermal Expansion (CTE) mismatch between the die and lid materials. The TIMs must maintain excellent adhesion to both the die and lid surfaces in order to achieve and maintain optimal thermal performance. The CTE mismatch leads to increased mechanical stress and degradation of the TIM, which in turn degrades the thermal performance. In this work, the effective modulus of several TIMs was calculated by finite element modeling (FEM) in concert with mechanical testing of thin bond-line aluminum-TIM sandwiches subjected to varied stress conditions. These results are correlated to the corresponding stress die shear testing and the impact on package performance is analyzed.

scholarly journals Effect of Epoxy Molding Compound Material and Roughness Leadframe to Integrated Circuit Package for Automotive Devices

2020 ◽  
Vol 18 (2) ◽  
pp. 179-188
Author(s):  
Anan Sukantharat ◽  
Kessararat Ugsornrat ◽  
Chalermsak Sumithpibul
Keyword(s):  
Integrated Circuit ◽  
Coefficient Of Thermal Expansion ◽  
Type A ◽  
Type B ◽  
Epoxy Molding Compound ◽  
Molding Compound ◽  
Material Type ◽  
Compound Material ◽  
Cte Mismatch ◽  
Compound Materials

This research studied about an effect of epoxy molding compound material and roughness leadframe of integrated circuit package for automotive device. In manufacturing process, the epoxy molding compound material and leadframe roughness are main factors that effect to coefficient of thermal expansion (CTE) and reliability for automotive device package with no delamination in high temperature application. In experiment, two types of epoxy molding compound materials were studied and compared between standard and roughened leadframe for quad flat non lead (QFN) package. For reliability test, the epoxy molding compound materials type A and type B with different leadframe were analyzed with moisture sensitivity level 1 to observe delamination inside packages. The results showed that CTE of epoxy molding compound material type A is less CTE mismatch than that of epoxy molding compound material type B with both standard and roughness leadframe. Moreover, the results also found no delamination for epoxy molding compound material type A with roughened leadframe. In addition, both epoxy molding compound materials showed significant delamination inside packages with standard leadframe.

Analyzing the Impact of X-Ray Tomography on the Reliability of Integrated Circuits

2015 ◽  
Author(s):  
Halit Dogan ◽  
Md Mahbub Alam ◽  
Navid Asadizanjani ◽  
Sina Shahbazmohamadi ◽  
Domenic Forte ◽  
...  
Keyword(s):  
Integrated Circuits ◽  
Integrated Circuit ◽  
3D Imaging ◽  
Three Dimensional ◽  
Serial Sectioning ◽  
Promising Technique ◽  
Flash Memories ◽  
X Ray ◽  
3D Information ◽  
The Impact

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).

scholarly journals Reducing environmental impacts from garments through best practice garment use and care, using the example of a Merino wool sweater

2021 ◽  
Author(s):  
Stephen G. Wiedemann ◽  
Leo Biggs ◽  
Quan V. Nguyen ◽  
Simon J. Clarke ◽  
Kirsi Laitala ◽  
...  
Keyword(s):  
Environmental Impacts ◽  
Energy Demand ◽  
Best Practice ◽  
Western Europe ◽  
Impact Category ◽  
Fashion Industry ◽  
Worst Case ◽  
Multiple Users ◽  
Washing Machines ◽  
The Impact

Abstract Purpose Garment production and use generate substantial environmental impacts, and the care and use are key determinants of cradle-to-grave impacts. The present study investigated the potential to reduce environmental impacts by applying best practices for garment care combined with increased garment use. A wool sweater is used as an example because wool garments have particular attributes that favour reduced environmental impacts in the use phase. Methods A cradle-to-grave life cycle assessment (LCA) was used to compare six plausible best and worst-case practice scenarios for use and care of a wool sweater, relative to current practices. These focussed on options available to consumers to reduce impacts, including reduced washing frequency, use of more efficient washing machines, reduced use of machine clothing dryers, garment reuse by multiple users, and increasing number of garment wears before disposal. A sixth scenario combined all options. Worst practices took the worst plausible alternative for each option investigated. Impacts were reported per wear in Western Europe for climate change, fossil energy demand, water stress and freshwater consumption. Results and discussion Washing less frequently reduced impacts by between 4 and 20%, while using more efficient washing machines at capacity reduced impacts by 1 to 6%, depending on the impact category. Reduced use of machine dryer reduced impacts by < 5% across all indicators. Reusing garments by multiple users increased life span and reduced impacts by 25–28% across all indicators. Increasing wears from 109 to 400 per garment lifespan had the largest effect, decreasing impacts by 60% to 68% depending on the impact category. Best practice care, where garment use was maximised and care practices focussed on the minimum practical requirements, resulted in a ~ 75% reduction in impacts across all indicators. Unsurprisingly, worst-case scenarios increased impacts dramatically: using the garment once before disposal increased GHG impacts over 100 times. Conclusions Wool sweaters have potential for long life and low environmental impact in use, but there are substantial differences between the best, current and worst-case scenarios. Detailed information about garment care and lifespans is needed to understand and reduce environmental impacts. Opportunities exist for consumers to rapidly and dramatically reduce these impacts. The fashion industry can facilitate this through garment design and marketing that promotes and enables long wear life and minimal care.

Influence of nozzle exit geometrical parameters on supersonic jet decay

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Prasanta Kumar Mohanta ◽  
B. T. N. Sridhar ◽  
R. K. Mishra
Keyword(s):  
Aspect Ratio ◽  
Nozzle Exit ◽  
Ambient Air ◽  
Schlieren Image ◽  
Geometrical Parameters ◽  
Image Study ◽  
Aspect Ratios ◽  
Core Length ◽  
Supersonic Core Length ◽  
The Impact

Abstract Experiments and simulations were carried on C-D nozzles with four different exit geometry aspect ratios to investigate the impact of supersonic decay characteristics. Rectangular and elliptical exit geometries were considered for the study with various aspect ratios. Numerical simulations and Schlieren image study were studied and found the agreeable logical physics of decay and spread characteristics. The supersonic core decay was found to be of different length for different exit geometry aspect ratio, though the throat to exit area ratio was kept constant to maintain the same exit Mach number. The impact of nozzle exit aspect ratio geometry was responsible to enhance the mixing of primary flow with ambient air, without requiring a secondary method to increase the mixing characteristics. The higher aspect ratio resulted in better mixing when compared to lower aspect ratio exit geometry, which led to reduction in supersonic core length. The behavior of core length reduction gives the identical signature for both under-expanded and over-expanded cases. The results revealed that higher aspect ratio of the exit geometry produced smaller supersonic core length. The aspect ratio of cross section in divergent section of the nozzle was maintained constant from throat to exit to reduce flow losses.

Aluminum Reflow Sputtering

MRS Bulletin ◽  
1995 ◽  
Vol 20 (11) ◽  
pp. 53-56 ◽  
Author(s):  
Kuniko Kikuta
Keyword(s):  
Integrated Circuit ◽  
High Speed ◽  
Lower Cost ◽  
High Reliability ◽  
Device Fabrication ◽  
Damascene Process ◽  
Aspect Ratios ◽  
Multi Level ◽  
Poor Adhesion ◽  
Lower Resistivity

The scaling of integrated-circuit device dimensions in the horizontal direction has caused an increase in aspect ratios of contact holes and vias without a corresponding scaledown in vertical dimensions. Conventional sputtering has become unreliable for handling higher aspect-ratio via/contact holes because of its poor step coverage. Several studies have attempted to overcome this problem by using W-CVD and reflow technology. The W-CVD is used for practical device fabrications. However, this technique has several problems such as poor adhesion to SiO2, poor W surface morphology, greater resistivity than Al, and the need of an etch-back process.Al reflow technology using a conventional DC magnetron sputtering system can simplify device-fabrication processes and achieve high reliability without Al/W interfaces. In particular, the Al reflow technology is profitable for multi-level interconnections in combination with a damascene process by using Al chemical mechanical polishing (CMP). These interconnections are necessary for miniaturized and high-speed devices because they provide lower resistivity than W and simplify fabrication processes, resulting in lower cost.This article describes recent Al reflow sputtering technologies as well as application of via and interconnect metallization.

Anomalous Dielectric Variability in the central peak of Tycho crater on the Moon: New insights from Mini-RF S-band Observations

2021 ◽  
Author(s):  
Shashwat Shukla ◽  
Gerald Wesley Patterson
Keyword(s):  
Dielectric Constant ◽  
Hyperspectral Image ◽  
Central Peak ◽  
Skin Depth ◽  
The Moon ◽  
Near Surface ◽  
Low Dielectric ◽  
Crater Morphology ◽  
High Dielectric ◽  
The Impact

&lt;p&gt;One of the unique candidates to explore the evolution of physical surface processes on the Moon is Tycho, a dark haloed impact crater representing well-preserved bright ray pattern and intact crater morphology. Sampling of the central peak in such complex crater formation proves significant in terms of unraveling intriguing science of the lunar interior. With the current state-of-the-art radar technology, it is possible to evaluate the response of the geologic features constrained in the near surface and subsurface regolith environments. This can be achieved by modelling the dielectric constant of media, which is a physical parameter crucial for furthering our knowledge about the distribution of materials within different stratigraphic layers at multiple depths. Here, we used the applicability of Mini-RF S-band data augmented with a deep learning based inversion model to retrieve the dielectric variations over the central peak of the Tycho crater. A striking observation is made in certain regions of the central peak, wherein we observe anomalously high dielectric constant, not at all differentiated in the hyperspectral image and first Stokes parameter image, which usually is a representation of retrieved backscatter of the target. The results are also supported by comparing the variations in the scattering mechanisms. We found those particular regions to be associated with high degree of depolarization, thereby attributing to the presence of cm- to m- scale scatterers buried within a low dielectric layer that are not big enough to produce even-bounce geometry for the radar wave. Moreover, we also observe high rock concentration in the central peak slopes from DIVINER data and NAC images, indicating the exposure of clasts ranging in size from 10 meter to 100s of meter. Furthermore, from surface temperature data, these distinctive outcrops sense warmer temperature at night than the surrounding, which suggests the existence of thermal skin depth in such vicinities. Interestingly, we are able to quantify the pessimistic dielectric constant limit of the large boulder in the middle of the central peak, observable at the Mini-RF radar wavelength, as 4.54 + j0.077. Compared to the expected dielectric constant of rocks, this value is lowered significantly. One probable reason could be the emergence of small radar shadows due to the rugged surface of the boulder on the radar illuminated portion. From our analysis, we showcase the anomalous dielectric variability of Tycho central peak, thereby providing new insights into the evolution of the impact cratering process that could be important for both science and necessary for framing human or robotic exploration strategies.&amp;#160;&amp;#160;&lt;/p&gt;

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