A novel CMOS architecture utilizing tensilekompressive silicon nitride capping layers to induce tensilekompressive strain in NMOSFETPMOSFET channel regions was developed. NMOSFET device delivers 1.05mA/pm on-current for 7OnA/pm off-current at 1V drain voltage. PMOS device exhibits peak 66% increase of linear drain current and 55% increase of saturation current. It was shown that drain current improvements both for N-and PMOSFETs strongly correlate with channel doping levels. Therefore, advanced methods of shallow and low resistance junction formation are required for maintaining low channel doping concentration and efficiently utilizing channel strain at sub40nm gate length.

A finer interconnection pitch of LSI packages has enhanced the importance of precise prediction technology of temperature-dependent warpage. In our research, we prepared a model package with minute wiring and vias, and examined a method of improving the agreement accuracy between numerical analysis and measurement of temperature-dependent warpage. To improve the precision of warpage prediction technology, we paid attention to warpage measurement technology, especially the temperature distribution in a sample, in addition to improving the accuracy of the numerical analysis model and material properties. We succeeded in heating a substrate with a temperature difference of 20°C or 3°C between the top side and bottom side, by controlling the heating conditions. Furthermore, the numerical analysis with a fine wiring model was performed under conditions where the temperature varied in consideration of the thermal conductivity of the substrate. The material properties for the numerical analysis, such as Coefficient of Thermal Expansion and Relaxation Modulus were measured very carefully with original setups, because they are essential for improving the accuracy of our numerical analysis.As a result, we found that substrate warpage with an uneven temperature distribution is quite different from such warpage with uniform temperature. To predict the temperature-dependent warpage with a high accuracy, we found that the temperature distribution in a substrate should be considered in the numerical analysis, besides applying the precise model and material properties.978-1-4244-4476-2/09/$25.00 ©2009 IEEE

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Crack density, main crack length and the sum total length of micro-cracks, which initiated and extended on the surface of a 500 MPa strength steel and its weld metal, were investigated by a replica technique applied during fatigue tests. The base and weld metal specimens were subjected to constant amplitude, random and block strain cycling. The base metal specimens were further tested under 4 kinds of block cycling and 2 kinds of incremental strain cycling. All the cumulative cycling patterns in random and block modes followed the so-called p-distribution.As a result of an analysis of micro-cracks, it was shown that the most useful parameter to estimate the accumulated fatigue damage was the sum total length of micro-cracks in a unit area, which increased exponentially with cycle ratio. Empirical formulae were obtained expressing the increasing tendency as a function of the cycle ratio for three groups of the equivalent strain amplitude. The formulae were applicable to all strain cycling patterns investigated in the present study. NOMENCLATURE D = Crack density. Number of cracks of length larger than 10 microns in an area of 0.1 mm2. I = Main (longest) crack length. ZnOr = Normalized main crack length= I at N cycles divided by 1 at N , cycles. L= Total crack length in an area of 0.1 mm2 (summation of products of crack length and number of cracks of the same length. (mm/O.l mm2) Lo, = Normalized total crack length = L at N cycles divided by L at N , cycles. n or N = Number of cycles imposed. N , = Visible crack initiation life (number of cycles to the initiation of a N , = Failure life (number of cycles to a tensile load decay down to less than p=Ratio of the maximum strain amplitude to the minimum strain surface fatigue crack of about 0.3 mm long). 40 MPa). amplitude in a block. eta = Longitudinal, natural, and total strain amplitude. (%). E~ = Equivalent strain amplitude, = E~, , = Theoretical equivalent strain amplitude, = (%), where t = 1 in the present study, and j = N, means 6) at N,. 8 In n i l (%) si, E, = Strain amplitude in a step.