Effects of Thickness and Oxygen Content on Thermomechanical Behavior of Thin Cu Films Passivated with Ain

1999 ◽  
Vol 563 ◽  
Author(s):  
J. Shu ◽  
S. Clyburn ◽  
T. Mates ◽  
S. P. Baker

AbstractThe thermomechanical behavior of a Cu thin film can be dramatically influenced (“oxygen effect”) by exposing the film to a small amount of air or oxygen prior to passivation. Film exposure is accomplished by breaking vacuum at some point prior to passivation. When the top surface is exposed immediately before passivation, the oxygen effect is produced when the passivation material is Si3N4, but no effect is seen with AIN passivations. However, the effect is seen in AIN passivated films when the Cu film surface is exposed to air or O2 and additional Cu is deposited before passivation. This suggests that conditions at the film/passivation interface are an important factor in this anomalous plasticity effect. We have investigated the effects of film thickness and oxygen concentration on these behaviors by preparing films with different thicknesses and oxygen contents for thermomechanical analysis. The thermomechanical behavior is correlated with secondary ion mass spectrometry (SIMS) data that shows oxygen concentration vs. film depth. The presence of the “oxygen effect” in thermomechanical behavior is found to be correlated with an increased oxygen concentration near the film/passivation and film/barrier interfaces.

2012 ◽  
Vol 472-475 ◽  
pp. 1451-1454
Author(s):  
Xue Hui Wang ◽  
Wu Tang ◽  
Ji Jun Yang

The porous Cu film was deposited on soft PVDF substrate by magnetron sputtering at different sputtering pressure. The microstructure and electrical properties of Cu films were investigated as a function of sputtering pressure by X-ray diffraction XRD and Hall effect method. The results show that the surface morphology of Cu film is porous, and the XRD revealed that there are Cu diffraction peaks with highly textured having a Cu-(220) or a mixture of Cu-(111) and Cu-(220) at sputtering pressure 0.5 Pa. The electrical properties are also severely influenced by sputtering pressure, the resistivity of the porous Cu film is much larger than that fabricated on Si substrate. Furthermore, the resistivity increases simultaneously with the increasing of Cu film surface aperture, but the resistivity of Cu film still decreases with the increasing grain size. It can be concluded that the crystal structure is still the most important factor for the porous Cu film resistivity.


2002 ◽  
Vol 721 ◽  
Author(s):  
Peter Klaver ◽  
Barend J. Thijsse

AbstractMolecular Dynamics simulations were performed to study Cu film deposition on β-Ta. Three different β-Ta surfaces were used, two being atomically flat, and one resulting from Ta on Ta growth. We find that the Cu films develop a (111) texture with vertical grain boundaries between grains having different epitaxial relations with the β-Ta substrate. The epitaxial rotation angles were determined, as 5.2° and 10-13°, and the resulting strain reductions in the Cu films were identified. The effects of the substrate differences on the interfacial Ta/Cu intermixing and the epitaxy and grain boundary structure of the films are discussed.


2005 ◽  
Vol 875 ◽  
Author(s):  
M. Gregoire ◽  
S. Kordic ◽  
P. Gergaud ◽  
O. Thomas ◽  
M. Ignat

AbstractThe thermomechanical behavior is investigated of SiCN-encapsulated blanket Physical Vapor Deposited (PVD) and Electrochemically Deposited (ECD) Cu films. At lower ECD Cu film thicknesses an anomalous shape and a tail of the stress-temperature curve are observed, which are not caused by impurities at the interfaces, but are correlated to highly textured microstructure. Repeated thermal cycling of up to 400 °C does not markedly change the texture of the films, but a significant texture change takes place with increasing ECD Cu thickness. Thermal cycling induces grain growth for thicker films only. Impurity content and distribution in the PVD films do not change due to cycling.


2009 ◽  
Vol 1156 ◽  
Author(s):  
Conal E. Murray ◽  
Paul R. Besser ◽  
Christian Witt ◽  
Jean L. Jordan-Sweet

AbstractGlancing-incidence X-ray diffraction (GIXRD) has been applied to the investigation of depth-dependent stress distributions within electroplated Cu films due to overlying capping layers. 0.65 μm thick Cu films plated on conventional barrier and seed layers received a CVD SiCxNyHz cap, an electrolessly-deposited CoWP layer, or a CoWP layer followed by a SiCxNyHz cap. GIXRD and conventional X-ray diffraction measurements revealed that strain gradients were created in Cu films possessing a SiCxNyHz cap, where a greater in-plane tensile stress was generated near the film / cap interface. The constraint imposed by the SiCxNyHz layer during cooling from the cap deposition temperature led to an increase in the in-plane stress of approximately 180 MPa from the value measured in the bulk Cu. However, Cu films possessing a CoWP cap without a SiCxNyHz layer did not exhibit depth-dependent stress distributions. Because the CoWP capping deposition temperature was much lower than that employed in SiCxNyHz deposition, the Cu experienced elastic deformation during the capping process. Cross-sectional transmission electron microscopy indicated that the top surface of the Cu films exhibited extrusions near grain boundaries for the samples undergoing the thermal excursion during SiCxNyHz deposition. The conformal nature of these caps confirmed that the morphological changes of the Cu film surface occurred prior to capping and are a consequence of the thermal excursions associated with cap deposition.


1995 ◽  
Vol 396 ◽  
Author(s):  
Seok-Keun Koh ◽  
Young-Soo Yoon ◽  
Ki-Hwan Kim ◽  
Hong-Gui Jang ◽  
Hyung-Jin Jung

AbstractPartially ionized beam deposition of Cu thin films on glass at room temperature were carried out to fabricate Cu laser mirrors with good structural and reflectance properties. At a constant film thickness of 600 Å, the grain size of as-grown Cu films increased with acceleration voltage, and there was no indication of defects such as cracks and/or large pores in the film surface as shown in scanning electron microscopy images. Root-mean-square(Rms) surface roughnesses of the films with thicknesses of 600 Å were measured by atomic force microscopy. RmS surface roughness increased when acceleration voltage increased from 0 kV to 2 kV, but decreased at the acceleration voltage of 3 kV. RmS surface roughness of the film grown at 4 kV, however, increased again. At the acceleration voltage of 3 kV, reflectance of the films increased with the film thickness until 600 Å and decreased at the film thickness of 800 Å. The reflectance results showed that the Cu film deposited at 3 kV had higher reflectance than that of others. Our results suggest that it is possible to grow the Cu film with good structural and optical properties on glass substrate at room temperature by partially ionized beam deposition.


2011 ◽  
Vol 287-290 ◽  
pp. 3085-3088
Author(s):  
Yao Min Zhu ◽  
Shan Shan Wang ◽  
Feng Zhang Ren

Electroplating was employed to prepare Cu films and Ni films on Ag substrates. The average internal stresses in Cu film and Ni film were measured in situ by cantilever beam test. The values of experimental internal stresses were compared with theoretical internal stresses. The results showed that the internal stresses of Cu film and Ni film decreased with the increase of the film thickness. The reduced gradient was faster. The values of experimental and theoretical internal stresses had the same variation trend with film thickness and the same characteristics (tensile stress). Theoretical calculation model of internal stress was of accuracy. The internal stress for the same substrate was in relation to the film material.


1993 ◽  
Vol 8 (8) ◽  
pp. 1845-1852 ◽  
Author(s):  
M.D. Thouless ◽  
J. Gupta ◽  
J.M.E. Harper

The reliability of integrated-circuit wiring depends strongly on the development and relaxation of stresses that promote void and hillock formation. In this paper an analysis based on existing models of creep is presented that predicts the stresses developed in thin blanket films of copper on Si wafers subjected to thermal cycling. The results are portrayed on deformation-mechanism maps that identify the dominant mechanisms expected to operate during thermal cycling. These predictions are compared with temperature-ramped and isothermal stress measurements for a 1 μm-thick sputtered Cu film in the temperature range 25–450 °C. The models successfully predict both the rate of stress relaxation when the film is held at a constant temperature and the stress-temperature hysteresis generated during thermal cycling. For 1 μm-thick Cu films cycled in the temperature range 25–450 °C, the deformation maps indicate that grain-boundary diffusion controls the stress relief at higher temperatures (>300 °C) when only a low stress can be sustained in the films, power-law creep is important at intermediate temperatures and determines the maximum compressive stress, and that if yield by dislocation glide (low-temperature plasticity) occurs, it will do so only at the lowest temperatures (<100 °C). This last mechanism did not appear to be operating in the film studied for this project.


2013 ◽  
Vol 284-287 ◽  
pp. 118-122 ◽  
Author(s):  
Ying Chih Wu ◽  
Yu Jung Huang ◽  
Ming Kun Chen ◽  
Yi Lung Lin ◽  
Ling Sheng Jang

The thin flexible Polyimides (PI) films have desirable properties for use in the electrical and electronics industry because their good thermal stability, high flexibility, low dielectric constants, excellent mechanical strength, low loss tangent, low relative permittivity and electrical insulating properties. In order to determine the process window of the surface metallization of PI, the fine traces with 50 micron pitch (25micron line /space) built on a flexible 50 micron thick PI film using wet fabrication process are reported in this paper. The thick copper (Cu) film was obtained from the Cu plating process using evaporated thin film of Cu as the adhesion layer. The fabricated fanout fine patterns are further investigated using scanning electron microscope (SEM), energy-dispersive spectrometry (EDS) and X-ray spectrometry technologies. The experiment is conducted to study the effect of the process parameters on the Cu film surface properties. The results obtained in this work can be applied to the fabrication of flexible microelectronic devices.


2004 ◽  
Vol 449-452 ◽  
pp. 681-684
Author(s):  
Jung Sik Kim

In the present study, thermal properties of the electroless-deposited Cu thin film were investigated. The Cu thin film of good adhesion was successfully deposited on the TaN barrier layer by a electroless deposition method. The multilayered structure of Cu/TaN/Si was prepared by electroless-depositing the Cu thin layer on the TaN diffusion barrier which was deposited by MOCVD on the Si substrate. In order to investigate the effect of post-heat treatment the specimen was annealed in H2 reduction atmosphere. Crystallization and agglomeration of the electroless-deposited Cu film occurred through annealing at H2 atmosphere and resulted in the decrease of film resistance. Thermal stability of Cu/TaN/Si system was maintained up to the annealing temperature of 600°C in H2 atmosphere above which the intermediate compound of Cu-Si was formed through diffusion into the TaN layer


1997 ◽  
Vol 505 ◽  
Author(s):  
Shane A. Catledge ◽  
Yogesh K. Vohra

ABSTRACTLow temperature diamond deposition on metal substrates is motivated by the need to reduce thermal stress so that the film adhesion is satisfactory. Although the use of oxygen-con- taining gas mixtures have been shown to extend the temperature range for which diamond can grow as well as to improve film quality, most studies have focused on the use of silicon as sub- strates and have neglected technologically important metallic systems. To this end, microwave plasma chemical vapor deposition (MPCVD) was used to grow diamond films on Ti-6A1-4V alloy at low temperature (615 to 780 C) using CH4/O2/H2 and CO/H2 gas mixtures. In-situ pyrometric interferometry (ISPI) shows that as the oxygen concentration increases, the onset time for dia- mond nucleation and subsequent film surface roughness increases while the average growth rate decreases. Micro-Raman spectroscopy shows improved film quality and suggests a trend toward increasing in-plane compressive stress with increasing oxygen concentration. Glancing-angle x- ray diffraction (XRD) was complimentary to the Raman data and indicates the presence of a TiC interfacial layer thickness which decreases with increasing oxygen concentration. We found that the CO/H2 mixture resulted in poorly adhered “white soot” films with low diamond content whereas the CH4/O2/H2 mixture yielded well adhered high quality diamond films.


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