scholarly journals Fracture patterns in thin films and multilayers

2003 ◽  
Vol 795 ◽  
Author(s):  
Alex A. Volinsky ◽  
Dirk C. Meyer ◽  
Tilmann Leisegang ◽  
Peter Paufler
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Residual Stress ◽  
Stress Relief ◽  
Fracture Pattern ◽  
External Stress ◽  
Final Fracture ◽  
Fracture Patterns ◽  
Buckling Delamination ◽  
Applied Stresses

ABSTRACTWhile there are many stress relief mechanisms observed in thin films, excessive residual and externally applied stresses cause film fracture. In the case of tensile stress a network of through-thickness cracks forms in the film. In the case of compressive stress thin film buckling is observed in the form of blisters. Thin film delamination is an inseparable phenomenon of buckling. The buckling delamination blisters can be either circular, straight, or form periodic buckling patterns commonly known as telephone cord delamination morphology.While excessive biaxial residual stress is the key for causing thin film fracture, either in tension, or compression, it is the influence of the external stress that can control the final fracture pattern. In this paper we consider phone cord buckling delamination observed in compressed W/Si and TiWN/GaAs thin film systems, as well as spiral and sinusoidal though-thickness cracks observed in Mo/Si multilayers under 3-point high-temperature bending in tension.

Crystallinity Control of Electroplated Interconnections for Improving Their Stability and Lifetime

2016 ◽  
Author(s):  
Jiatong Liu ◽  
Ken Suzuki ◽  
Hideo Miura
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Residual Stress ◽  
Grain Boundaries ◽  
Lattice Mismatch ◽  
Bulk Material ◽  
Chemical Properties ◽  
Mechanical Fracture ◽  
Copper Thin Film ◽  
Electroplated Copper

In a three-dimensional (3D) packaging systems, the interconnections which penetrate stacked silicon chips have been employed. Such interconnection structure is called TSV (Through Silicon Via) structure, and the via is recently filled by electroplated copper thin film. The electroplated copper thin films often consist of fine columnar grains and porous grain boundaries with high density of defects which don’t appear in conventional bulk material. This unique micro texture has been found to cause the wide variation of physical and chemical properties of this material. In the TSV structure, the shrinkage of the copper thin film caused by thermal deformation and recrystallization of the unique texture during high-temperature annealing is strictly constrained by surrounding rigid Si and thus, high tensile residual stress remains in the thin film after thermal annealing. High residual stress should give rise to mechanical fracture of the interconnections and the shift of electronic function of thin film devices formed in Si. Therefore, the residual stress in the interconnections should be minimized by controlling the appearance of the porous boundaries during electroplating for assuring the longterm reliability of the interconnections. As the lattice mismatch between Cu and its barrier film (Ta) is as larger as 18%, which is the main reason for the fine columnar structures and porous grain boundaries, it is necessary to control the underlayer crystallinity to improve the crystallinity of electroplated copper thin films. In this study, the effective method for controlling the crystallinity of the underlayer was investigated by improving the atomic configuration in the electroplated copper thin film. The result showed that by controlling the crystallinity of underlayer, crystallinity of electroplated copper thin films can be improved, the mechanical properties of thin films was improved and thus, stability and lifetime of electroplated copper interconnections can be improved.

scholarly journals Thin film stress and microstructure analysis by energy-dispersive diffraction

2014 ◽  
Vol 70 (a1) ◽  
pp. C724-C724
Author(s):  
Christoph Genzel
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Residual Stress ◽  
Film Growth ◽  
High Energy ◽  
Energy Dispersive ◽  
Film Stress ◽  
Ex Situ ◽  
Near Surface

The most important advantage of energy dispersive (ED) diffraction compared with angle dispersive methods is that the former provides complete diffraction patterns in fixed but arbitrarily selectable scattering directions. Furthermore, in experiments that are carried out in reflection geometry, the different photon energies E(hkl) of the diffraction lines in an ED diffraction pattern can be taken as an additional parameter to analyze depth gradients of structural properties in the materials near surface region. For data evaluation advantageous use can be made of whole pattern methods such as the Rietveld method, which allows for line profile analysis to study size and strain broadening [1] or for the refinement of models that describe the residual stress depth distribution [2]. Concerning polycrystalline thin films, the features of ED diffraction mentioned above can be applied to study residual stresses, texture and the microstructure either in ex-situ experiments or in-situ to monitor, for example, the chemical reaction pathway during film growth [3]. The main objective of this talk is to demonstrate that (contrary to a widespread opinion) high energy synchrotron radiation and thin film analysis may fit together. The corresponding experiments were performed on the materials science beamline EDDI at BESSY II which is one of the very few instruments worldwide that is especially dedicated to ED diffraction. On the basis of selected examples it will be shown that specially tailored experimental setups allow for residual stress depth profiling even in thin films and multilayer coatings as well as for fast in situ studies of film stress and microstructure evolution during film growth.

scholarly journals Evolution of Principle and Practice of Electrodeposited Thin Film: A Review on Effect of Temperature and Sonication

2011 ◽  
Vol 2011 ◽  
pp. 1-16 ◽  
Author(s):  
A. Mallik ◽  
B. C. Ray
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Mechanical Properties ◽  
Residual Stress ◽  
Electrochemical Deposition ◽  
Surface Engineering ◽  
Effect Of Temperature ◽  
Structure And Morphology ◽  
Nucleation Mechanisms ◽  
Effects Of Temperature

This review discusses briefly the important aspects of thin films. The introduction of the article is a summary of evolution of thin films from surface engineering, their deposition methods, and important issues. The fundamental aspects of electrochemical deposition with special emphasis on the effect of temperature on the phase formation have been reviewed briefly. The field of sonoelectrochemistry has been discussed in the paper. The literature regarding the effects of temperature and sonication on the structure and morphology of the deposits and nucleation mechanisms, residual stress, and mechanical properties has also been covered briefly.

scholarly journals Effect of Ion Energy on the Microstructure and Properties of Titanium Nitride Thin Films Deposited by High Power Pulsed Magnetron Sputtering

Coatings ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 579
Author(s):  
Donglin Ma ◽  
Qiaoyuan Deng ◽  
Huaiyuan Liu ◽  
Yongxiang Leng
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Residual Stress ◽  
Magnetron Sputtering ◽  
Titanium Nitride ◽  
High Power ◽  
Substrate Bias Voltage ◽  
Ion Energy ◽  
Tools Wear ◽  
Pulsed Magnetron

Titanium nitride (Ti-N) thin films are electrically and thermally conductive and have high hardness and corrosion resistance. Dense and defect-free Ti-N thin films have been widely used in the surface modification of cutting tools, wear resistance components, medical implantation devices, and microelectronics. In this study, Ti-N thin films were deposited by high power pulsed magnetron sputtering (HPPMS) and their plasma characteristics were analyzed. The ion energy of Ti species was varied by adjusting the substrate bias voltage, and its effect on the microstructure, residual stress, and adhesion of the thin films were studied. The results show that after the introduction of nitrogen gas, a Ti-N compound layer was formed on the surface of the Ti target, which resulted in an increase in the Ti target discharge peak power. In addition, the total flux of the Ti species decreased, and the ratio of the Ti ions increased. The Ti-N thin film deposited by HPPMS was dense and defect-free. When the energy of the Ti ions was increased, the grain size and surface roughness of the Ti-N film decreased, the residual stress increased, and the adhesion strength of the Ti-N thin film decreased.

Controlled Stress Refractory Metallizations

2001 ◽  
Vol 695 ◽  
Author(s):  
Ilan Golecki ◽  
Margaret Eagan
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Residual Stress ◽  
Vapor Deposition ◽  
Physical Vapor Deposition ◽  
Ion Beam ◽  
Residual Tensile Stress ◽  
Electrically Conductive ◽  
Complete Control ◽  
Chemical Inertness

ABSTRACTRhodium and iridium are highly electrically conductive refractory metals, which can be used as current-carrying thin-film metallizations. Their chemical inertness further enables their application at relatively high temperatures. However, due to the high elastic modulus of such metals, a residual tensile stress of 300 to 400 MPa is measured in evaporated thin films. We present novel results evidencing complete control over both the magnitude and the sign of the residual stress in such refractory thin films. The metallic layers are deposited by means of ion-beam-enhanced physical vapor deposition and both electrical resistivity and stress are controlled. Controlling the stress in this manner has enabled achieving thicker films and films with near-zero residual stress.

Stress-Induced and Electro-Migration of Electroplated Copper Thin Film Interconnections Used for 3D Integration

2011 ◽  
Author(s):  
Naoki Saito ◽  
Naokazu Murata ◽  
Kinji Tamakawa ◽  
Ken Suzuki ◽  
Hideo Miura
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Residual Stress ◽  
Grain Boundaries ◽  
Current Density ◽  
Annealed Film ◽  
Applied Current ◽  
Copper Thin Film ◽  
Applied Current Density ◽  
Electroplated Copper

Electroplated copper thin films have started to be applied to not only interconnections in printed wiring boards, but also thin film interconnections and TSV (Through Silicon Via) in semiconductor devices because of its low electric resistivity and high thermal conductivity. Thus, the electrical reliability of the electroplated copper interconnections was investigated experimentally. Self-made electroplated copper thin film interconnections were used for the evaluation. Electroplating conditions are as follows. The thin film interconnections were made by damascene process for electromigration tests. The applied current density during the test was varied from 1 MA/cm2 to 10 MA/cm2. Abrupt fracture caused by the local fusion was often observed in the as-electroplated interconnections within a few hours during the test. Since there were a lot of porous grain boundaries in the as-electroplated thin films, the local high Joule heating should have caused the fusion at one of the porous grain boundaries. Actually, it was confirmed that the failure rate increased linearly with the square of the amplitude of the applied current density. However, the diffusion of copper atoms caused by electromigration was enhanced significantly when the film was annealed at 400°C. Many voids and hillocks were observed on their surfaces. This change of the fracture mode clearly indicates the improvement of the crystallographic quality of the annealed film. It was also observed that the stress-induced migration was activated substantially in the annealed film. Large voids and hillocks grew during the custody of the film even at room temperature without any application of current. This stress-induced migration was caused by the increase of residual tensile stress of about 200 MPa in the annealed film. It was also found that sulfur atoms segregated in the grown hillocks, though no sulfur atoms were found by EDX in the initial as-electroplated interconnections or other area in the annealed thin film interconnections. Thus, the hillock formation in the annealed interconnections was enhanced by the segregation of sulfur atoms. These sulfur atoms should have been introduced into the electroplated films during electroplating. Therefore, it is very important to control the micro texture, the residual stress and the concentration of sulfur in the electroplated copper thin film interconnections to assure the stable life, in other words, to eliminate their sudden brittle fracture and time-dependent degradation caused by the residual stress in the thin film interconnections.

High Quality AlN Thin Films Deposited by Middle-Frequency Magnetron Sputtering at Room Temperature

2014 ◽  
Vol 787 ◽  
pp. 227-231 ◽  
Author(s):  
Chuan Li ◽  
Lin Shu ◽  
Li Jun He ◽  
Xing Zhao Liu
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Residual Stress ◽  
Aluminum Nitride ◽  
Buffer Layer ◽  
Room Temperature ◽  
Residual Tensile Stress ◽  
High Quality ◽  
Polycrystalline Aluminum ◽  
Aln Buffer

A study of depositing high quality c-axis oriented polycrystalline aluminum nitride thin film at room temperature was presented. Aluminum nitride films were grown by mid-frequency (MF) reactive sputtering. Metallic aluminum target was used to deposit AlN films in Ar/N2 gas mixture. A 50nm thick of N-rich AlN buffer layer was deposited at the initial stage of sputtering process to improve the film quality. The composition, preferred orientation and residual stress of the films were analyzed by EDS, XRD and Raman microscope, respectively. The results showed that the N-rich AlN buffer layer improved the textured degree and reduced the residual stress significantly of the AlN thin films. The near stoichiometric AlN thin film with highly textured degree was obtained. The FWHM value of the rocking curve for (0002) diffraction peak was about 1.6°, and the residual tensile stress was about 500MPa. The piezoelectric d33 coefficient increased with the decreasing of FWHM value, and the highest d33 coefficient of 3.6 pF/C was obtained.

scholarly journals Experiments with in-situ thin film telephone cord buckling delamination propagation

2002 ◽  
Vol 749 ◽  
Author(s):  
Alex A. Volinsky
Keyword(s):  
Thin Film ◽  
Residual Stress ◽  
Compressive Residual Stress ◽  
In Situ Observation ◽  
Crack Healing ◽  
Buckling Delamination ◽  
Film Substrate ◽  
Delamination Propagation ◽  
Analysis Of Motion

ABSTRACTThere are many different stress relief mechanisms observed in thin films. One of the mechanisms involves film debonding from the substrate. In the case of tensile residual stress a network of through-thickness cracks forms in the film. In the case of compressive residual stress thin film buckling and debonding from the substrate in the form of blisters is observed. The buckling delamination blisters can be either straight, or form periodic buckling patterns commonly known as telephone cord delamination morphology.The mechanics of straight-sided blisters is well understood. Current study relies on the in-situ observation of phone cord delamination propagation in different thin film/substrate systems. Both straight and phone cord delaminations are shown to simultaneously propagate in the same film system. Straight-sided blisters propagate several times faster than the phone cords, and may be followed by thin film fracture along the line of maximum film buckling amplitude. Phone cord delaminations originally start as straight-sided blisters, but then deviate to the periodic phone cord geometry due to the fact that the compressive residual stress in the film is biaxial. Digital analysis of motion recordings shows that partial crack “healing” is present at the curved portions of the phone cords due to the “secondary” buckling pushing thin film back to the substrate. These experimental observations allow for the correct interpretation of the telephone cord delamination morphology.

scholarly journals Micro-fluidic applications of telephone cord delamination blisters

2004 ◽  
Vol 855 ◽  
Author(s):  
Alex A. Volinsky ◽  
Patrick Waters ◽  
Gregory Wright
Keyword(s):  
Thin Films ◽  
Residual Stress ◽  
Argon Pressure ◽  
Inexpensive Method ◽  
Directional Growth ◽  
Interfacial Toughness ◽  
Micro Fluidics ◽  
Buckling Delamination ◽  
Sputter Deposited ◽  
Stored Elastic Energy

ABSTRACTArgon pressure significantly affects the residual stress in sputter deposited thin films and coatings. In case of W thin films, high residual stresses on the order of 1–2 GPa are quite common. With the rest of sputtering parameters being equal, argon pressure determines the sign and the value of residual stress.When the amount of stored elastic energy in the film due to the residual stress exceeds the interfacial toughness, fracture normally occurs. Telephone cord buckling delamination blisters are commonly observed in compressed thin films. These mechanically active features form by a loss of adhesion between the film and the substrate due to residual stress relief, and exhibit directional growth under certain conditions. This paper considers telephone cord delamination channels for micro-fluidics applications, as this could to be a valuable, reliable, and inexpensive method of forming open channels.

Sign in / Sign up

Export Citation Format

Share Document