Effect of gold layer thickness on the characteristics of flip-chip interconnects

Author(s):  
W.S. Chai ◽  
M. Gupta ◽  
A.A.O. Tay ◽  
J.F.J. Caers
2020 ◽  
Vol 10 ◽  
pp. 184798042098211
Author(s):  
Najmiah Radiah Mohamad ◽  
Mohd Farhanulhakim Mohd Razip Wee ◽  
Mohd Ambri Mohamed ◽  
Azrul Azlan Hamzah ◽  
P Susthitha Menon

Kretschmann-based surface plasmon resonance sensor utilizing chromium and gold nanofilms is ideal for label-free biomedical sensing. In this work, Taguchi’s L9 orthogonal array method was used to optimize the effects of three control factors and noise factor, which are the incident optical wavelength, chromium and gold nanofilm thicknesses, and their root-mean-square surface roughness, on the performance of the Kretschmann-based surface plasmon resonance sensor. The control factors were varied at three levels for a novel multi-response optimization of the Kretschmann-based surface plasmon resonance sensor for the minimum reflectivity, the full-width-at-half-maximum, and the sensitivity of 3% glucose detection, executed using Lumerical’s two-dimensional finite-difference time-domain method. Using Taguchi method, the best control factor setting in air was A3B2C2 corresponding to 785 nm optical wavelength, 0.5 nm chromium, and 50 nm gold layer thickness, respectively, with minimum reflectivity of 0.0017%, full-width-at-half-maximum of 0.4759°, and glucose-sensing sensitivity of 106.73°·RIU−1. The detection accuracy and quality factor were 0.01 and 224.26 RIU−1, respectively. It was also indicated that chromium nanofilm thickness of 0.5–3 nm and its root-mean-square surface roughness has a negligible factor effect compared to other control factors. Taguchi method’s factor effect analysis showed that for chromium layer thickness of 1–3 nm, the minimum reflectivity values are predominantly determined by the gold layer thickness with 75% factor effect, followed by optical wavelength with 11%. Factor effect of full-width-at-half-maximum is determined by optical wavelength (57%), followed by gold layer thickness (38%). Sensitivity is 88% determined by optical wavelength and 10% determined by gold layer thickness. The Kretschmann-based surface plasmon resonance glucose sensor with the best glucose-sensing sensitivity was at optical wavelength of 632.8 nm with a higher sensitivity value of 163.415°·RIU−1 but lower detection accuracy and quality factor values of 0.001 and 24.86 RIU−1, respectively, compared to near-infrared wavelength of 785 nm. In conclusion, finite-difference time-domain and Taguchi method is suitable for multi-response optimization of control and noise factors of Kretschmann-based surface plasmon resonance sensors.


2002 ◽  
Vol 736 ◽  
Author(s):  
Stéphanie Périchon Lacour ◽  
Zhenyu Huang ◽  
Zhigang Suo ◽  
Sigurd Wagner

ABSTRACTThe electro-mechanical response of thin gold layers evaporated onto silicone substrates is reported. Gold layers are prepared either thin and flat or thin and wavy on the compliant substrate. The electrical resistance of gold/silicone stripes is measured and analyzed during tensile deformation. For a 100-nm thick gold layer evaporated on a 1-mm thick silicone membrane, we have observed electrical continuity up to ∼ 22 % strain. This maximum strain decreases when the gold layer thickness is raised.


2003 ◽  
Vol 125 (4) ◽  
pp. 609-616 ◽  
Author(s):  
G. B. Dou ◽  
Y. C. Chan ◽  
Johan Liu

In anisotropic conductive adhesive (ACA) interconnections, the particles are electrical conductors providing current paths in the fine pitch electronic packaging as well as physical parts connecting with the chip bumps and the substrate pads through the mechanical deformation interfaces. The primary object of this fundamental research is to reveal the electrical conductive characteristics of Ni/Au coated resin particles. Such an ACA particle resistance is resulted from two metal coated layers, which are two parallel resistors in the circuit determined by the particle transformation degree. In order to investigate the effect of the particle transformation degree upon the particle resistance, the particle transformation factor is defined. The mathematical electrical resistance function of an ACA particle, an integral function of the transformation factor and the particle geometries, resin diameter, nickel layer thickness, and gold layer thickness, is worked out from the physical model of an ACA particle. To carry out the solutions of the function, MathCAD software is applied. According to the numerical solutions, the deeper the particle transformation, the thicker the metal coated layer thicknesses and the longer the resin diameter are, the lower the particle resistance is. In conclusion, it is stated that the ACA particle resistance is determined by the particle transformation and the particle geometries, however, the transformation and the nickel layer thickness are more sensitive than the resin diameter and the gold layer thickness. Finally, the resistance function will explain the conductive mechanism of the deformed ACA particle.


2005 ◽  
Vol 297-300 ◽  
pp. 863-868
Author(s):  
Dae Gon Kim ◽  
Hyung Sun Jang ◽  
Jong Woong Kim ◽  
Seung Boo Jung

In the present work, we investigated the interfacial reactions and shear properties between Sn-3.0Ag-0.5Cu flip chip solder bump and Cu UBM after multiple reflows. The quantitative analyses of the intermetallic compound layer thickness as a function of the number of reflows were performed. After six reflows, the reaction product could be distinguished by two intermetallic compounds: Cu3Sn adjacent to the substrate and Cu6Sn5 which was the dominant phase. The thickness of total intermetallic compound layers increased with the number of reflows. The shear strength value did not significantly change as a function of the number of reflows. Nearly all of the test specimens showed ductile failure mode, and this could be well explained with the results of FEM analyses.


Author(s):  
Alain Claverie ◽  
Zuzanna Liliental-Weber

GaAs layers grown by MBE at low temperatures (in the 200°C range, LT-GaAs) have been reported to have very interesting electronic and transport properties. Previous studies have shown that, before annealing, the crystalline quality of the layers is related to the growth temperature. Lowering the temperature or increasing the layer thickness generally results in some columnar polycrystalline growth. For the best “temperature-thickness” combinations, the layers may be very As rich (up to 1.25%) resulting in an up to 0.15% increase of the lattice parameter, consistent with the excess As. Only after annealing are the technologically important semi-insulating properties of these layers observed. When annealed in As atmosphere at about 600°C a decrease of the lattice parameter to the substrate value is observed. TEM studies show formation of precipitates which are supposed to be As related since the average As concentration remains almost unchanged upon annealing.


Author(s):  
H. Kung ◽  
A.J. Griffin ◽  
Y.C. Lu ◽  
K.E. Sickafus ◽  
T.E. Mitchell ◽  
...  

Materials with compositionally modulated structures have gained much attention recently due to potential improvement in electrical, magnetic and mechanical properties. Specifically, Cu-Nb laminate systems have been extensively studied mainly due to the combination of high strength, and superior thermal and electrical conductivity that can be obtained and optimized for the different applications. The effect of layer thickness on the hardness, residual stress and electrical resistivity has been investigated. In general, increases in hardness and electrical resistivity have been observed with decreasing layer thickness. In addition, reduction in structural scale has caused the formation of a metastable structure which exhibits uniquely different properties. In this study, we report the formation of b.c.c. Cu in highly textured Cu/Nb nanolayers. A series of Cu/Nb nanolayered films, with alternating Cu and Nb layers, were prepared by dc magnetron sputtering onto Si {100} wafers. The nominal total thickness of each layered film was 1 μm. The layer thickness was varied between 1 nm and 500 nm with the volume fraction of the two phases kept constant at 50%. The deposition rates and film densities were determined through a combination of profilometry and ion beam analysis techniques. Cross-sectional transmission electron microscopy (XTEM) was used to examine the structure, phase and grain size distribution of the as-sputtered films. A JEOL 3000F high resolution TEM was used to characterize the microstructure.


Author(s):  
Masahiro Ito ◽  
Yuitch Iwagaki ◽  
Hiroshi Murakami ◽  
Kenji Nemoto ◽  
Masato Yamamoto ◽  
...  

Sign in / Sign up

Export Citation Format

Share Document