Development of a Novel Test Setup to Study the Combined Effects of Electromigration and Thermomechanical Stress in Solder Interconnects

2021 ◽  
Author(s):  
David Huitink ◽  
Mahsa Montazeri
Keyword(s):  
Combined Effects ◽  
Thermomechanical Stress ◽  
Test Setup ◽  
Solder Interconnects

Development of a Novel Test Setup to Study the Combined Effects of Electromigration and Mechanical Stress in Solder Interconnects

2020 ◽  
Author(s):  
Mahsa Montazeri ◽  
David R. Huitink
Keyword(s):  
Tensile Stress ◽  
Thermal Cycling ◽  
Current Density ◽  
Flip Chip ◽  
High Current Density ◽  
Operating Conditions ◽  
Reliability Estimation ◽  
High Current ◽  
Test Setup ◽  
Solder Interconnects

Abstract One key concern that arises from scaling of device interconnects with increasing power density requirements is electromigration (EM). On the other hand, thermal cycling fatigue has always been a reliability challenge in solder interconnects. Variations in device temperature caused by environmental or operating conditions induce stress in solders, as they usually connect two components with different coefficients of thermal expansion (CTE). These thermally induced stresses may lead to crack formation within the solders. The combination of EM effects and thermal cycling add to the complexity of the reliability estimation for high current density applications. In this work, a novel test setup has been designed and developed to estimate the reliability of solder interconnects under high current density, while a constant tensile stress is also applied to the solder interconnect. The test set up offers the ability to test up to four samples at the same time. Additionally, the test samples are fabricated with two copper wires connected by Pb/Sn solder to imitate copper UBM in a flip-chip bonding connection. Strain in solder is measured by monitoring the elongation of the wire during testing, while failure of the connection is detected by continuous monitoring of the electrical resistance. The experiment is conducted for conditions including pure tensile stress, pure EM and coupled EM and tensile stress where a significant reduction in life-time is observed for the coupled degradation effects. Comparing the experimental results of different current densities at different stress levels will help in identifying the nature of degradation in solders, which will help inform the drive for miniaturization.

Effects of Retinoic Acid and 1,25-Dihydroxyvitamin D3 on IFN-gamma Secretion by Mononuclear Leukocytes from Nulliparous and Postparturient Dairy Cattle

2000 ◽  
Vol 70 (3) ◽  
pp. 92-101 ◽  
Author(s):  
Burim Ametaj ◽  
Brian Nonnecke ◽  
Ronald Horst ◽  
Donald Beitz
Keyword(s):  
Retinoic Acid ◽  
Dairy Cattle ◽  
Dairy Cows ◽  
Dairy Cow ◽  
Pokeweed Mitogen ◽  
Mononuclear Leukocytes ◽  
Combined Effects ◽  
Ifn Gamma ◽  
Dihydroxyvitamin D ◽  
1,25 Dihydroxyvitamin D

Individual and combined effects of several isomers of retinoic acid (RA) and 1,25-dihydroxyvitamin D3 (1,25-(OH)2D3) on interferon-gamma (IFN-gamma) secretion by blood mononuclear leukocytes (MNL) from nulliparous and postparturient Holstein cattle were evaluated in vitro. In the first experiment, effects on incubation period (24 to 72 hours) and time of supplementation (0 to 32 hours) with all-trans, 9-cis, 13-cis-, and 9,13-dicis-RAs (0 to 100 nM) on IFN-gamma secretion by pokeweed mitogen (PWM)-stimulated (0 and 10 mug/ml) MNL from nulliparous cattle were evaluated. In the second experiment, MNL from postparturient cows (bled at 0, 2, 4, and 16 days postpartum) were stimulated with PWM (0 and 10 mug/ml) in the presence of RA isomers (9-cis- or 9,13-dicis-RA; 0 to 100 nM), 1,25-(OH)2D3 (0 to 100 nM), or with combinations of these metabolites. The results show that individual isomers of RA had no effect on IFN-gamma secretion by PWM-stimulated MNL from nulliparous or postparturient cows. Furthermore 1,25-dihydroxyvitamin D3 inhibited IFN-gamma secretion by MNL from nulliparous and postparturient dairy cows; however, the degree of inhibition was greater when 9-cis- and 9,13-dicis-RA were also present in the cultures. Finally mononuclear leukocytes from postparturient dairy cows produced substantially less IFN-gamma than did MNL from nulliparous cattle. It is concluded that retinoic acids individually did not affect the capacity of leukocytes from dairy cattle to secrete IFN-gamma. This result is in marked contrast to studies in monogastric species indicating that RAs inhibit IFN-gamma secretion by peripheral blood T cells. Inhibition of IFN-gamma secretion by 1,25-(OH)2D3 was potentiated by 9-cis- and 9,13-di-cis-retinoics acids, suggesting that an excess of dietary vitamins A and D may compromise further the naturally immunosuppressed postparturient dairy cow. Additional research is necessary to determine if the combined effects of these metabolites on IFN-gamma secretion represent an increased susceptibility of the dairy cow to infectious diseases during the periparturient period. Lower secretion of IFN-gamma by MNL from postpartutient dairy cows, relative to nulliparous cattle, suggests that recently-calved cows are naturally immunosuppressed.

Combined effects of form- and meaning-based predictability on perceived clarity of speech.

2018 ◽  
Vol 44 (2) ◽  
pp. 277-285 ◽  
Author(s):  
Carine Signoret ◽  
Ingrid Johnsrude ◽  
Elisabet Classon ◽  
Mary Rudner
Keyword(s):  
Combined Effects

Combined effects of the prosteatotic TM6SF2 and PNPLA3 variants on severity of NALFD: multicentre biopsy-based study in German patients

2015 ◽  
Vol 53 (12) ◽  
Author(s):  
M Krawczyk ◽  
M Rau ◽  
J Schattenberg ◽  
H Bantel ◽  
A Pathil ◽  
...  
Keyword(s):  
Combined Effects

Mechanisms leading to recruitment inhibition of giant kelp Macrocystis pyrifera by an understory alga

2021 ◽  
Vol 657 ◽  
pp. 59-71
Author(s):  
BA Beckley ◽  
MS Edwards
Keyword(s):  
Field Experiments ◽  
Local Community ◽  
Kelp Forest ◽  
Macrocystis Pyrifera ◽  
Forest Recovery ◽  
Kelp Forests ◽  
Giant Kelp ◽  
Combined Effects ◽  
Life Stages ◽  
Survival And Growth

The forest-forming giant kelp Macrocystis pyrifera and the communities it supports have been decreasing across their native ranges in many parts of the world. The sudden removal of giant kelp canopies by storms increases space and light for the colonization by understory macroalgae, such as Desmarestia herbacea, which can inhibit M. pyrifera recovery and alter local community composition. Understanding the mechanisms by which algae such as D. herbacea interact with M. pyrifera can provide insight into patterns of kelp forest recovery following these disturbances and can aid in predicting future community structure. This study experimentally tested the independent and combined effects of two likely competitive mechanisms by which D. herbacea might inhibit recovery of M. pyrifera in the Point Loma kelp forest in San Diego, California (USA). Specifically, we conducted field experiments to study the individual and combined effects of shade and scour by D. herbacea on the survival of M. pyrifera microscopic life stages, and the recruitment, survival, and growth of its young sporophytes. Our results show that scour had the strongest negative effect on the survival of M. pyrifera microscopic life stages and recruitment, but shade and scour both adversely affected survival and growth of these sporophytes as they grew larger. Canopy-removing storms are increasing in frequency and intensity, and this change could facilitate the rise of understory species, like D. herbacea, which might alter community succession and recovery of kelp forests.

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