Nitrogen plasma modification on polyimide films for copper metallization on microelectronic flex substrates

Surface modification of polyimide films Kapton E(N) and Upilex S by nitrogen plasmas were investigated for their enhanced adhesion strength with sputtered coppers. Peel tests demonstrate this improvement, with peel strengths of 7 and 12 N/m for unmodified Kapton E(N) and Upilex S, and 1522 and 1401 N/m for nitrogen plasma‐modified Kapton E(N) and Upilex S at certain plasma conditions. Atomic force microscopy (AFM) and the sessile drop method indicated the surface roughness, and the surface energy of polyimide films were highly increased by nitrogen plasmas. This study shows the enhanced adhesion strengths of polyimide films with sputtered coppers by nitrogen plasmas, and these nitrogen plasmas were strongly affected by the surface characteristics of polyimide films. Electron spectroscopy for chemical analysis (ESCA) observed the increased surface energy on polyimide films by nitrogen plasmas was due to the increased surface composition of O and the increased chemical bond of C? O. © 2005 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 43: 2023–2038, 2005     

Asymptotic theory of some tests for a possible change in the regression slope occurring at an unknown time point

Summary Based on least squares estimators and aligned rank order statistics, some testing procedures for a possible change in the regression slope occurring at an unknown time point are considered. The asymptotic theory of the proposed tests rests on certain invariance principles relating to least squares estimators and aligned rank order statistics, and these are developed here.Work supported by the National Heart, Lung and Blood Institute, Contract NIH-NHLBI-71-2243 from the (U.S.) National Institutes of Health     

On the Bahadur representation of sample quantiles for sequences of φ-mixing random variables

The object of the present investigation is to show that the elegant asymptotic almost-sure representation of a sample quantile for independent and identically distributed random variables, established by Bahadur [1] holds for a stationary sequence of φ-mixing random variables. Two different orders of the remainder term, under different φ-mixing conditions, are obtained and used for proving two functional central limit theorems for sample quantiles. It is also shown that the law of iterated logarithm holds for quantiles in stationary φ-mixing processes.     

Free-electron model and triplet-state lifetime of benzene

Using the free-electron model the triplet-state lifetime of benzene for the 330 mμ band has been estimated to be about 36 sec, which compares favourably with the corrected experimental value of 30 sec. It has also been established that the perturbing singlet must be a π-σ singlet rather than a π-π singlet.     

A study of the level properties of 57Co from the (τ, d) reaction on 56Fe

The ⁵⁶Fe(τ, d)⁵⁷Co reaction has been studied at E_τ = 18 MeV using the Tandem Van de Graaff accelerator and the multichannel magnetic spectrograph of the Nuclear Physics Laboratory, Oxford, Angular distributions have been measured for most of the levels up to E_x ≈ 7.8 MeV and are analysed in terms of the DWBA theory of direct reactions. The l_p values and the transition strengths compared with available theories.     

The decay of Cs

In a study of the level scheme of ¹³¹Cs, we have measured the γ-γ and the ce-γ directional correlations of the 496-123.7 keV and 486-133.5 keV cascades. The linear polarization at φ=90° was measured for the 496-123.7 keV and 486-133.5 keV cascades. The L-subshell ratios for the 123.7 keV transition were determined. The g-factor of the 133.5 keV level and the half-lives of the 78.7, 123.7, 133.5 and 216 keV levels were re-investigated. The spin and parity assignments derived for the 620, 133.5 and 123.7 keV levels are , respectively. The 620, 496, 486, 133.5 and 123.7 keV transitions are found to be of pure E2, pure M1, pure E2, (M1+(22±2)%E2) and pure E2 multipolarity, respectively. An upper limit of 192 ps for the half-life of the 216 keV level is obtained. The results are compared with theoretical estimates from the calculations of Kisslinger and Sorensen, of Freed and of Freed and Miles.