Shape evolution of electrodeposited bumps with deep cavity

Electrodeposited bumps are the indispensable microconnectors for high-density interconnection in the latest microelectronics applications. The deep cavities are especially important for the solder bumps for ball grid arrays. This investigation discusses the relation between cavity shapes and current distributions of deep cavities. The role of convection and diffusion within the cavities is calculated at diffusion-limited overpotentials with numerical fluid dynamics computations. The current distributions become symmetric and peak profiles become sharper for the deeper cavities of large aspect ratios and of negative photoresist angles, theta. For 30 mu m cathode length, the current at the center is larger than that at the edges for photoresist angles of theta less than or equal to 0. For these deep cavities, the convection outside the cavity is not related to the current distribution and the current distribution is determined by the cavity shape. The mass transport within the deep cavities is controlled mainly by diffusion. This is because the convection outside the cavities is not effectively stirring inside the deep cavities.</p

Shape evolution of electrodeposited copper bumps with high peclet numbers

We report the shape evolution of initial copper bumps at Peclet numbers higher than a hundred. The role of vortices and of penetration flow within the cavity was discussed with numerical fluid dynamics computation to obtain a bump with a single hump at the center. The current distributions, or flux profiles, were calculated at the diffusion controlled overpotential and were compared with the electrodeposited bump shapes. For the 100 mu m cavity width, the vortices increase at the upstream corners with Peclet numbers 1410 and 7311. The vortices are the local resistance of mass transfer to the cathode. These vortices cause the hollows in flux profiles at the upstream corner with these Peclet numbers. The penetration flow collides with the photoresist sidewall and the vortices decrease at downstream corners. These decreased vortices cause the increase in flux profile at downstream corners. For a 30 pm cavity width a single large vortex forms for the higher Peclet number 44,500 and a single hump in flux is achieved.</p

Exact lattice supersymmetry at the quantum level for N = 2 Wess–Zumino models in 1- and 2-dimensions

Supersymmetric lattice Ward-Takahashi identities are investigated perturbatively up to two-loop corrections for super doubler approach of N = 2 lattice Wess-Zumino models in 1- and 2-dimensions. In this approach, notorious chiral fermion doublers are treated as physical particles and momentum conservation is modified in such a way that lattice Leibniz rule is satisfied. The two major difficulties to keep exact lattice supersymmetry are overcome. This formulation defines, however, nonlocal field theory. Nevertheless we confirm that exact supersymmetry on the lattice is realized for all supercharges at the quantum level. Delicate issues of associativity are also discussed

Current evolution of electrodeposited copper bumps with photoresist angle

We report the current distribution of copper bumps with photoresist sidewall angles. The role of outer diffusion, vortices, and penetration flow within the cavity is discussed, with numerical fluid dynamics computed in order to prevent side bumping. The current distributions were calculated at the diffusion controlled overpotential. The mass transfer-limited current distribution showed that a zero or negative angle reduced diffusion from the outer surroundings and enhanced vortex formation at the cathode corners. Reduction in the diffusion and enhancement in vortices reduced current at the cathode corners and prevented side bumping.</p

ラットの膀胱内圧測定及び摘出膀胱収縮力に対する虚血の影響

ラットの両側内腸骨動脈を結紮し虚血ラット膀胱を作成し, この虚血膀胱におけるurethane麻酔下の膀胱内圧測定及び摘出膀胱の電気刺激, bethanechol, ATP, KClに対する収縮力を検討した.次いで一定速度で生理食塩水を膀胱内に注入しながら電気刺激を繰り返しvolume-pressure studyを実施した.膀胱の重量は虚血により有意に増大した.膀胱内圧曲線を分析した結果, 膀胱容量, 残尿量は増大し, 排尿筋収縮圧は減少した.この結果, 虚血に伴い排尿効率(排尿量/膀胱容量)は有意に減少した.摘出膀胱における排尿収縮力は, 全ての刺激に対して虚血後に低下した.volume-pressure studyの結果からin vitroの膀胱complianceは7日後減少し14日後は逆に増大したIschemia induced by atherosclerosis is a common cause of organ failure in the elderly. We investigated the effects of in vivo ischemia created by ligation of the internal iliac arteries on the parameters of in vivo infusion cystometry under urethane anesthesia and on in vitro whole bladder contractility of the rat. Bladder weight significantly increased after ischemia for 14 days. Infusion cystometry demonstrated that in the ischemic bladders the capacity increased, the voiding pressure decreased, and the volume of residual urine increased, which resulted in deteriorated voiding efficacy. The in vitro whole bladder contractility to field stimulation, bethanechol, ATP, and KCl was reduced by ischemia. The passive pressure increased as the bladder volume enlarged and the bladder compliance once decreased by ischemia on the 7th day, but increased on the 14th day. In an active volume-pressure relationship study the peak response was decreased by ischemia. The volume at which response reached a peak value shifted to a larger volume 14 days after surgery. In conclusion, ischemia impaired in vivo rat detrusor power to empty. Since detrusor contractility in vitro decreased in response to various kinds of stimulation, this deteriorated bladder function was supposed to be caused by muscle degeneration

Perspectives on enteral tube feeding in Japan

[Introduction] The purpose of this study was to investigate the differences in the preference of enteral tube feeding between elderly inhabitants of Mugi town, Tokushima Prefecture, Japan, and their parents in various physical conditions. [Methods] This population-based questionnaire survey studied 300 randomly selected participants aged 65–80 years. Respondents were to consider a situation where eating was difficult, and were questioned on their desire for tube feeding, using a visual analogue scale (VAS) ranging from “do not want tube feeding (0)” to “want tube feeding (100).” [Results] Valid responses of 103 (34.4%) participants were analyzed. Under conditions of being “healthy,” “bedridden,” “with dementia,” and “bedridden and with dementia,” the median (IQR) of the VAS values for the desire for tube feeding were 31.8 (3.3 to 83.8), 19.3 (2.4 to 52.3), 5.2 (0.7 to 18.9), 4.0 (0.3 to 15.2) for respondents and 55.2 (11.6 to 92.2), 48.7 (5.5 to 85.5), 9.0 (1.2 to 46.8), 5.1 (0.1 to 36.5) for parents, respectively. The VAS values for the parents were significantly higher (p=0.001, 0.002, 0.001, and 0.01, respectively for the four conditions described) for the same items. [Conclusion] Surrogate decisions made by family members often differ from what the patients would have desired