Zue-Chin Chang

Microstructure and shear strength of a Au–In microjoint

Abstract Two types of Au–In microjoints, i.e. Au/In/Au in which In foil was used and Au/In, were prepared by either solid state interdiffusion (SSID) or solid–liquid interdiffusion (SLID) bonding for single lap tensile test. Deposition of the Au and In thin films was carried out by thermal evaporation on a polyethylene terephthalate (PET) substrate. It is found that the shear strength of the Au/In microjoints is higher than that of Au/In/Au using In foil. It is also observed that the fracture mode of Au–In microjoints depends on the types of In used. Failure of the Au/In microjoints appeared to be along the joint–substrate interface, whereas it occurred within the In foil for the other type of specimens. Examination of the Au/In microjoints by glancing angle X-ray diffraction reveals the presence of the two major constituent phases, Au 7 In 3 and Au, as well as other intermetallics AuIn 2 , Au 10 In 3 , and Au 9 In 4 in small amount. On the other hand, only the intermetallic AuIn 2 and pure In were observed in the Au/In/Au microjoints, where the total thickness of In is much higher than that of Au.

Intermetallic phase formation and shear strength of a Au-In microjoint

Indium and its alloys exhibit good service life and reliability, and are well suited for applications such as solder interconnections in electronic packaging. In this study, two types of Au-In microjoints, i.e. Au/In/Au in which In foil was used and Au/In, were prepared by either solid state interdiffusion (SSID) or solid-liquid interdiffusion (SLID) bonding for single lap tensile test. Deposition of the Au and In thin films was carried out by thermal evaporation on a polyethylene terephthalate (PET) substrate. It is found that the shear strength of the Au/ In microjoints is higher than that of Au/In/Au using In foil. In addition, it is observed that the fracture mode of Au-In microjoints depends on the types of In used. Failure of the Au/In microjoints appeared to be along the joint-substrate interface, whereas it occurred within the In foil for the other type of specimens. Examination of the Au/In microjoints by glancing angle X-ray diffraction reveals the presence of the two major constitutent phases, Au7In3 and Au, as well as other intermetallics AuIn2, Au10In3, and Au9In4 in small amount. On the other hand, only the intermetallic AuIn2 and pure In were observed in the Au/In/Au microjoints, where the total thickness of In is much higher than that of Au.

Effect of metal vapor vacuum arc Cr-implanted interlayers on the microstructure of CrN film on silicon

c Abstract The effect of metal vapor vacuum arc (MEVVA) Cr-implanted interlayers on the microstructure of CrN films on the silicon wafer was investigated.Two types of the CrN-coated specimens (CrNySi and CrNyCrySi) by cathodic arc plasma deposition were prepared with and without a MEVVA Cr-implanted interlayer.The diffraction patterns of the coated specimens revealed the presence of CrN, and the (220) preferred orientation for both CrNySi and CrNyCrNySi.The CrN coating thicknesses for CrN y Si and for CrNyCrySi were 0.3 mm and 1.3 mm, respectively.Secondary ion mass spectrometry proved the high quality of the films on silicon substrates.Transmission electron microscopy micrographs and selective area diffractions revealed the presence of a large number of nano-scale Cr resulting from the interlayer of MEVVA Cr with a background of single crystal silicon spots. Furthermore, in situ stress measurement demonstrated that the presence of a Cr interlayer between CrN and Si could drastically reduce the residual stress in the CrNyCrySi assembly. 2003 Elsevier Science B.V. All rights reserved.

Characterization of the microstructure and phase formation in the Au-In system using transmission electron microscopy

The Au‐In system is of both fundamental and technical importance for engineering applications such as microelectronic packaging. The growth mechanism and crystal orientation of the Au and In thin films produced by thermal evaporation on NaCl substrates are studied by transmission electron microscopy (TEM). Like most metals, the growth of both Au and In thin films on single crystals of NaCl follows the Volmer‐Weber mode, i.e. formation of metal nuclei first, and then grain growth and coalescence of the particles to form a continuous thin film. In contrast, the growth of In on the Au-coated NaCl substrates follows the Frank‐van der Merwe mode, i.e. layer by layer, as a result of strong interactions between Au and In. The formation of AuIn2 phase occurs instantly upon In deposition, and the intermetallic exhibits an epitaxial orientation to the underlayer Au single crystals. In addition, cross-section TEM observation of the Au/In/Au thin sections by ultramicrotomy shows that the AuIn2 intermetallic is brittle.

Characterization and Formation Mechanism of Macroparticles in Arc Ion-Plated CrN Thin Films

The microstructure and chemistry of macroparticles in CrN films prepared by an arc ion-plating method on AISI 304 stainless steel was characterized by an energy filtering transmission electron microscope (TEM) equipped with an electron energy loss spectroscopy (EELS) detector. The surface morphology of the CrN coatings with macroparticles was examined by a high-resolution field emission scanning electron microscope (SEM). SEM observation shows that the macroparticles lie on craters and protrude out of the coating surface. Cross-sectional and plan-view TEM results reveal that the macroparticles are bud shape, which has the Cr metal located at the bottom center and surrounded by a chromium nitride layer. Quantitative EELS analysis of a macroparticle from the core region to the outer shell shows that the nitrogen and oxygen concentrations in the macroparticle increase from 17.7 to 38 atom % and 7.7 to 9.5 atom %, respectively, On the basis of the analysis, a model describing the formation of macroparticles in the arc ion-plated CrN coatings is proposed.

Influence of deposition parameters on the structure and optical property of Zn(S,O) films

This paper presents the influence of process parameters, including sputtering power, oxygen partial pressure (RO), and substrate temperature on the optical property of Zn(S,O) thin films fabricated by radio frequency magnetron sputtering technology and deposited on glass substrates. The chemical composition, structural and optical properties of the samples were investigated by electron spectroscopy for chemical analysis, X-ray diffraction, and spectrophotometer. All the films mainly exhibited β-ZnS phase with (111) preferred orientation. [S]/([S]+[O]) ratio increased at high sputtering power, low RO, and low substrate temperature. Moderate ranges in sputtering power and substrate temperature and low RO resulted in large grain size. Adatoms are expected to exhibit increased mobility under these conditions. Average transmittance exceeded 75% in the visible wavelength region. Bandgap under these conditions was dominated strongly by the change in grain size and [S]/([S]+[O]) ratio. Optical properties of Zn(S,O) thin films could be modified, which is promising for optoelectronic applications.