Thermomechanical Behavior and Properties of Passivated Pvd and Ecd Cu Thin Films

2005 ◽  
Vol 875 ◽  
Author(s):  
M. Gregoire ◽  
S. Kordic ◽  
P. Gergaud ◽  
O. Thomas ◽  
M. Ignat
Keyword(s):  
Thin Films ◽  
Thermal Cycling ◽  
Grain Growth ◽  
Impurity Content ◽  
Thermomechanical Behavior ◽  
Temperature Curve ◽  
Cu Films ◽  
Texture Change ◽  
Cu Film ◽  
Electrochemically Deposited

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.

Stress development and relaxation in copper films during thermal cycling

1993 ◽  
Vol 8 (8) ◽  
pp. 1845-1852 ◽  
Author(s):  
M.D. Thouless ◽  
J. Gupta ◽  
J.M.E. Harper
Keyword(s):  
Thermal Cycling ◽  
Integrated Circuit ◽  
Temperature Hysteresis ◽  
Copper Films ◽  
Cu Films ◽  
Dislocation Glide ◽  
Temperature Range ◽  
Cu Film ◽  
Relaxation Of Stresses ◽  
Power Law Creep

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.

RESIDUAL STRESS DEVELOPMENT IN CU THIN FILMS WITH AND WITHOUT AlN PASSIVATION BY CYCLIC PLANE BENDING

2010 ◽  
Vol 24 (15n16) ◽  
pp. 2530-2536
Author(s):  
MITSUHIKO SHINOHARA ◽  
TAKAO HANABUSA ◽  
KAZUYA KUSAKA
Keyword(s):  
Thin Films ◽  
Mechanical Properties ◽  
Diffraction Method ◽  
Micro Electro Mechanical System ◽  
Passivation Layer ◽  
X Ray Diffraction ◽  
Cu Films ◽  
Cu Film ◽  
Bending Fatigue Test ◽  
Plane Bending

Since the thin film technology is applied to micro-machines, MEMS (micro electro-mechanical system), optical devices and others, the evaluation of mechanical properties in thin films becomes to be important. On the other hand, there are differences in mechanical properties between bulk materials and thin films, but studies in this field have not yet been made enough. The present paper reports on the evaluation of the mechanical properties of Cu thin films with and without AlN passivation layer. Specimens with different thickness of Cu film were subjected to cyclic plane bending fatigue test. Residual stresses developed in the Cu films were measured in a sequence of bending cycles using X-ray diffraction method in order to understand the effect of film thickness and passivation layer on mechanical properties of Cu thin films.

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
Keyword(s):  
Oxygen Concentration ◽  
Secondary Ion Mass Spectrometry ◽  
Film Surface ◽  
Thermomechanical Analysis ◽  
Thermomechanical Behavior ◽  
Oxygen Effect ◽  
Cu Films ◽  
Passivation Film ◽  
Cu Film ◽  
Cu Thin Film

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.

Crystallographic texture change during abnormal grain growth in Cu‐Co thin films

1994 ◽  
Vol 65 (2) ◽  
pp. 177-179 ◽  
Author(s):  
J. M. E. Harper ◽  
J. Gupta ◽  
D. A. Smith ◽  
J. W. Chang ◽  
K. L. Holloway ◽  
...  
Keyword(s):  
Thin Films ◽  
Grain Growth ◽  
Crystallographic Texture ◽  
Abnormal Grain Growth ◽  
Texture Change

scholarly journals Nanoindentation of Au and Pt/Cu thin films at elevated temperatures

2004 ◽  
Vol 19 (9) ◽  
pp. 2650-2657 ◽  
Author(s):  
Alex A. Volinsky ◽  
Neville R. Moody ◽  
William W. Gerberich
Keyword(s):  
Thin Films ◽  
Elastic Modulus ◽  
Yield Stress ◽  
Elevated Temperatures ◽  
Nanocrystalline Structure ◽  
Cu Films ◽  
Interfacial Toughness ◽  
Film Hardness ◽  
Cu Film ◽  
Sputter Deposited

This paper describes the nanoindentation technique for measuring sputter-deposited Au and Cu thin films’ mechanical properties at elevated temperatures up to 130 °C. A thin, 5-nm Pt layer was deposited onto the Cu film to prevent its oxidation during testing. Nanoindentation was then used to measure elastic modulus and hardness as a function of temperature. These tests showed that elastic modulus and hardness decreased as the test temperature increased from 20 to 130 °C. Cu films exhibited higher hardness values compared to Au, a finding that is explained by the nanocrystalline structure of the film. Hardness was converted to the yield stress using both the Tabor relationship and the inverse method (based on the Johnson cavity model). The thermal component of the yield-stress dependence followed a second-order polynomial in the temperature range tested for Au and Pt/Cu films. The decrease in yield stress at elevated temperatures accounts for the increased interfacial toughness of Cu thin films.

Effect of oxygen on the thermomechanical behavior of passivated Cu thin films

2003 ◽  
Vol 18 (9) ◽  
pp. 2122-2134 ◽  
Author(s):  
Jonathan B. Shu ◽  
Susan B. Clyburn ◽  
Thomas E. Mates ◽  
Shefford P. Baker
Keyword(s):  
Thin Films ◽  
Thermal Cycling ◽  
Secondary Ion Mass Spectrometry ◽  
Thermomechanical Behavior ◽  
Silicon Substrates ◽  
Dislocation Glide ◽  
Before And After ◽  
Passivation Layers ◽  
Dislocation Energy ◽  
Effect Of Oxygen

The thermomechanical behavior of Cu thin films, 600–1125 nm thick and encapsulated between SiNx barrier and SiNx or AlNx passivation layers on silicon substrates, was studied during thermal cycling between room temperature and 400 or 500 °C using the substrate curvature method. Films were prepared with varying oxygen contents, and the distribution of oxygen through the thickness of selected films was studied before and after thermal cycling using secondary ion mass spectrometry. Large variations in the thermomechanical behavior with oxygen content were found and correlated with segregation of oxygen to the film/barrier and film/passivation interfaces. These variations are thought to be due to recovery of stored misfit dislocation energy, which is, in turn, controlled by oxygen in the film. Effects of oxygen on film deformation through variations in interfacial adhesion and diffusion-induced dislocation glide are considered.

Texture Evolution in Al(Cu) Interconnect Materials

2001 ◽  
Vol 672 ◽  
Author(s):  
C.E. Murray ◽  
K.P. Rodbell
Keyword(s):  
Grain Growth ◽  
Texture Evolution ◽  
Effective Diffusivity ◽  
Morphological Development ◽  
Island Growth ◽  
Cu Films ◽  
Cu Film ◽  
Island Coalescence ◽  
Cu Interconnect ◽  
Time Required

ABSTRACTAn investigation of the microstructural evolution of Al(Cu) thin films deposited on a variety of interlevel dielectric (ILD) layers was performed. A combination of X-ray texture measurements and scanning electron microscopy (SEM) was employed to link the texture behavior of the as-deposited Al(Cu) films at different thicknesses to the observed morphological development within the films. Three regimes of texture were revealed, corresponding to (1): Al(Cu) island growth and individual island coalescence, (2): fully coalesced film and the onset of grain growth and (3): extensive grain growth. The first and last of these regimes exhibited offset (111) texture, in which the maximum diffracted intensity from Al (111) is offset from the substrate normal. However, the position of maximum offset texture differed between the first and third stages of growth, indicating that two different mechanisms were responsible. The offset (111) texture observed in the third regime of Al(Cu) film microstructure was due to the faceting of grain surfaces. The time required for the films to reach these three stages depended on the effective diffusivity of the Al atoms on the ILD surfaces, which differed in chemistry and topography.

The Nanomechanical Effect of Dendrimer Interlayers Underneath Cu Ultrathin Films

2002 ◽  
Vol 734 ◽  
Author(s):  
Junyan Zhang ◽  
Micheal Curry ◽  
Shane Street
Keyword(s):  
Thin Films ◽  
Ultrathin Films ◽  
Room Temperature ◽  
Native Oxide ◽  
Cu Films ◽  
Dc Sputtering ◽  
Repeat Units ◽  
Cu Film

ABSTRACTTwo kinds of dendrimers, DAB and PAMAM (with the same terminal groups but different branched repeat units), were chosen as interlayers for Cu ultrathin films deposited on native oxide Si(100) wafers. 10 nm Cu thin films were deposited directly on the dendrimer monolayers by DC sputtering at room temperature. The nanomechanical results show that PAMAM and DAB have significant effects on the properties of the resulting films, with the DAB layer acting as a stiffer ‘spring’, compared to PAMAM, underneath the Cu films. Both dendrimer interlayers lower the hardness of the film, compared to Cu alone; the effect is greater for PAMAM than DAB interlayers. However, the introduction of either dendrimer monolayer significantly increased the elasticity of the Cu film.

In situ TEM Observations of Grain Growth in Nanograined Thin Films

2004 ◽  
Vol 854 ◽  
Author(s):  
K. Hattar ◽  
J. Gregg ◽  
J. Han ◽  
T. Saif ◽  
I. M. Robertson
Keyword(s):  
Thin Films ◽  
Grain Growth ◽  
Elevated Temperatures ◽  
Critical Role ◽  
Grain Structure ◽  
In Situ Tem ◽  
Free Standing ◽  
Transmission Electron Microscopy Analysis ◽  
Cu Films

ABSTRACTIn situ transmission electron microscopy analysis is used to study the stability of nanograined and ultra-fine grained thin films at elevated temperatures. In the free-standing Au and Cu films, grain growth was dependent on annealing temperature and time with growth observed in both materials at temperatures greater than 373K. Both materials exhibited abnormal grain growth although it was more prevalent in Au than in Cu, which may be a consequence of pinning of the Cu grain boundaries by impurities. The formation and destruction of twins was observed to play a critical role in the grain growth, with the twins retarding the growth in gold, but not in Cu. In constrained Au films no grain growth was observed on annealing at temperatures below 636 K. At 636 K, the eutectic temperature, the microstructure transformed to the eutectic structure with the first stage being the annihilation of the grain structure.

Effect of Film Thickness on the Annealing Texture in Sputtered and Electroplated Cu Films

2006 ◽  
Vol 15-17 ◽  
pp. 982-988
Author(s):  
Sang Hoon Lee ◽  
No Jin Park ◽  
David P. Field ◽  
Paul R. Besser
Keyword(s):  
Film Thickness ◽  
Grain Growth ◽  
Processing Conditions ◽  
X Ray ◽  
Cu Films ◽  
Annealing Texture ◽  
Cu Film ◽  
The Relationship ◽  
Si Wafer

For optimum fabrication and usage of Cu films, an understanding of the relationship between processing and microstructure is required. The existence of twins is another significant factor for texture development in Cu films. Texture character and strength in the Cu film is dependent on the twin boundary development that is a function of processing conditions and film thickness. In this study, determination of grain growth and texture in the sputtered and electroplated Cu films during annealing was performed for films of 100, 480 and 850 nm in thickness deposited on a Ta(25 nm)/Si wafer. The texture was measured by X-ray pole figure. The effect of film thickness on the annealing texture in the sputtered and electroplated Cu films is examined and discussed.

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