Microfabricated elastomeric scaffolds with 3D structural patterns are created by semi-automated layer-by-layer assembly of planar polymer sheets with through-pores. The meso-scale interconnected pore architectures governed by the relative alignment of layers are shown to direct cell and muscle-like fiber orientation in both skeletal and cardiac muscle, enabling scale up of tissue constructs towards clinically relevant dimensions.

No abstract

It is becoming increasingly clear that understanding the small scale polishing mechanisms operating during CMP requires knowledge of the nature of the pad-wafer contact. Dual Emission Laser Induced Fluorescence (DELIF) can be used to study the fluid layer profile between the polishing pad and the wafer during CMP. Interactions between the polishing pad surface and the wafer can then be deduced from the fluid layer profile. We present a technique and some preliminary data for instantaneous measurement of in-situ pad-wafer contact, defined as the point at which the fluid film thickness goes to zero, using DELIF. The imaging area is 1.30mmx1.74 mm with a resolution of 2.

Registry No. H02C(CH2)5C02H-4-H0C6H4C6H40H-4 copolymer, 86129-23-9; H02C(CH2)6C02H-4-H0C6H4C6H40H-4 (SRU), 74790-60-6; H02C(CH2)6C02H-4-H0C6H4C6H40H-4 copolymer, 86129-24-0; H02C(CH2)6C02H-4-H0C6H4C6H40H-4 (SRU), 74790-61-7; H02C(CH2)7C02H-4-H0C6H4C6H40H-4 copolymer, 86129-25-1; H02C(CH2)7C02H-4-H0CeH4C6H40H-4 (SRU), 86129-19-3; H02C(CH2)8C02H-4-H0C6H4C6H40H-4 copolymer, 70788-15-7; H02C(CH2)8C02H-4-H0C6H4C6H40H-4 (SRU), 70800-12-3; H02C(CH2)9C02H-4-H0C6H4C6H40H-4 copolymer, 86129-26-2; H02C(CH2)9C02H-4-H0C6H4C6H40H-4 (SRU), 86129-20-6; HO2C(CH2)10CO2H-4-HOC6H4C6H4OH-4 copolymer, 86129-27-3; HO2C(CH2)10CO2H-4-HOC6H4CeH4OH-4 (SRU), 86129-21-7; H02C(CH2)nC02H-4-H0C6H4C6H40H-4 copolymer, 86129-28-4; H02C(CH2)11C02H-4-H0C6H4C6H40H-4 (SRU), 86129-22-8; H02C(CH2)12C02H-4-H0C6H4C6H40H-4 copolymer, 86129-29-5; H02C(CH2)12C02H-4-H0C6H4C6H40H-4

Recent experimental advances using dual emission laser induced fluorescence and image processing have provided high spatial and temporal resolution maps of the slurry layer during chemical mechanical polishing ͑CMP͒. Intensity differences in the images correspond to fluid layer thickness variations as the slurry passes between different pad and wafer topographies. Asperities expand under 14 µm deep wells and are compressed beyond the trailing edge of the well. Air pockets travel from the leading to the trailing edge of the wafer through 27 µm deep wells. The pads tested were Freudenberg FX9, Rodel IC1000, and experimental pads from Cabot Microelectronics.

Dual Emission Laser Induced Fluorescence (DELIF) is employed to attempt to experimentally determine the nature of the lubrication regime in Chemical Mechanical Planarization. Our DELIF setup provides images of the polishing slurry between the wafer and pad. Static images were taken to provide a baseline, then dynamic runs were conducted. Analyzing these images shows that the wafer only contacts the pad in a small number of places around the wafer, mainly due to the pad's topography.

In this paper, nano impact printing of silk biopolymer films is described. An indenter is rapidly accelerated and transfers the nanopattern from a silicon master into the silk film during an impact event that occurs in less than 1 ms. Contact stresses of greater than 100 MPa can be achieved during the short impact period with low power and inexpensive hardware. Ring shaped features with a diameter of 2 μm and a ring width of 100-200 nm were successfully transferred into untreated silk films using this method at room temperature. Mechanical modeling was carried out to determine the contact stress distribution, and demonstrates that imprinting can occur for contact stresses of less than 2 MPa. Thermal characterization at the impact location shows that raising the temperature to 70 • C has only a limited effect on pattern transfer. Contact stresses of greater than approximately 100 MPa result in excessive deformation of the film and poor pattern transfer.

In this work, we propose a model to quantify strain induced conductor discontinuities based on measuring electrical resistance while applying tensile strain to metal-polymer systems. Under strain, changing conductor geometry and induced conductor discontinuity increase electrical resistance. On Kapton substrates strained to ε = .07, evaporated gold films did not deform and resistance increase was only caused by geometry change. Conversely, discontinuity caused 31% and 72% of the resistance increase in evaporated and printed silver films at the same strain. On PDMS substrates, the same magnitude of discontinuity, causing 31% of the resistance increase, occurred at only ε = .024 in evaporated silver films. At the same strain, discontinuity caused 86% of the resistance increase in evaporated gold films. Printed silver films were inelastic. The results suggest that traditional fabrication techniques may be more suitable to flexible hybrid electronics applications than additively manufactured conductors.