Mechanical Properties of Electroplated Copper Thin Films

1999 ◽  
Vol 594 ◽  
Author(s):  
R. Spolenak ◽  
C. A. Volkert ◽  
K. Takahashi ◽  
S. Fiorillo ◽  
J. Miner ◽  
...  
Keyword(s):  
Thin Films ◽  
Mechanical Properties ◽  
Grain Size ◽  
Film Thickness ◽  
Yield Stress ◽  
Laser Scanning ◽  
Focused Ion Beam ◽  
Ion Beam ◽  
Cu Films ◽  
Electroplated Copper

AbstractIt is well known that the mechanical properties of thin films depend critically on film thickness However, the contributions from film thickness and grain size are difficult to separate, because they typically scale with each other. In one study by Venkatraman and Bravman, Al films, which were thinned using anodic oxidation to reduce film thickness without changing grain size, showed a clear increase in yield stress with decreasing film thickness.We have performed a similar study on both electroplated and sputtered Cu films by using chemical-mechanical polishing (CMP) to reduce the film thickness without changing the grain size. Stress-temperature curves were measured for both the electroplated and sputtered Cu films with thicknesses between 0.1 and 1.8 microns using a laser scanning wafer curvature technique. The yield stress at room temperature was found to increase with decreasing film thickness for both sets of samples. The sputtered films, however, showed higher yield stresses in comparison to the electroplated films. Most of these differences can be attributed to the different microstructures of the films, which were determined by focused ion beam (FIB) microscopy and x-ray diffraction.

The Mechanical Properties of Electroplated Cu Thin Films Measured by means of the Bulge Test Technique

2001 ◽  
Vol 695 ◽  
Author(s):  
Yong Xiang ◽  
Xi Chen ◽  
Joost J. Vlassak
Keyword(s):  
Mechanical Properties ◽  
Film Thickness ◽  
Yield Stress ◽  
Young’S Modulus ◽  
Young's Modulus ◽  
Bulge Test ◽  
X Ray Diffraction ◽  
Test Technique ◽  
Cu Films ◽  
Analytical Formulae

ABSTRACTThe mechanical properties of freestanding electroplated Cu films were determined by measuring the deflection of Si-framed, pressurized membranes. The films were deformed under plane-strain conditions. The pressure-deflection data are converted into stress-strain curves by means of simple analytical formulae. The microstructure of the Cu films was characterized using scanning electron microscopy and x-ray diffraction. The yield stress, Young's modulus, and residual stress were determined as a function of film thickness and microstructure. Both yield stress and Young's modulus increase with decreasing film thickness and correlate well with changes in the microstructure and texture of the films.

The yield stress of polycrystalline thin films

1993 ◽  
Vol 8 (2) ◽  
pp. 237-238 ◽  
Author(s):  
C.V. Thompson
Keyword(s):  
Thin Films ◽  
Grain Size ◽  
Film Thickness ◽  
Yield Stress ◽  
Size Dependence ◽  
Detailed Understanding ◽  
Polycrystalline Thin Films ◽  
Observed Behavior

In recent experiments it has been shown that the yield stress of polycrystalline thin films depends separately on the film thickness and the grain size. It was also shown that the grain size dependence varies as the reciprocal of the grain size. In this paper an analysis is presented which leads to these results and provides a more detailed understanding of the origins of the observed behavior.

scholarly journals Effect of Annealing on Microstructure and Mechanical Properties of Magnetron Sputtered Cu Thin Films

2015 ◽  
Vol 2015 ◽  
pp. 1-8 ◽  
Author(s):  
Shiwen Du ◽  
Yongtang Li
Keyword(s):  
Thin Films ◽  
Mechanical Properties ◽  
Residual Stress ◽  
Grain Size ◽  
Strain Energy ◽  
Texture Coefficient ◽  
Elastic Strain Energy ◽  
Interface Energy ◽  
Cu Films ◽  
Si Substrates

Cu thin films were deposited on Si substrates using direct current (DC) magnetron sputtering. Microstructure evolution and mechanical properties of Cu thin films with different annealing temperatures were investigated by atomic force microscopy (AFM), X-ray diffraction (XRD), and nanoindentation. The surface morphology, roughness, and grain size of the Cu films were characterized by AFM. The minimization of energy including surface energy, interface energy, and strain energy (elastic strain energy and plastic strain energy) controlled the microstructural evolution. A classical Hall-Petch relationship was exhibited between the yield stress and grain size. The residual stress depended on crystal orientation. The residual stress as-deposited was of tension and decreased with decreasing of (111) orientation. The ratio of texture coefficient of (111)/(220) can be used as a merit for the state of residual stress.

Laser Induced High-Strain-Rate Superplastic 3D Micro-Forming of Metallic Thin Film

2009 ◽  
Author(s):  
Huang Gao ◽  
Gary J. Cheng
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Film Thickness ◽  
Strain Rate ◽  
Focused Ion Beam ◽  
Laser Intensity ◽  
Ion Beam ◽  
Micro Forming ◽  
Forming Process ◽  
Metal Thin Films

Microforming of metals has always been a challenge because of the limited formability of metals at micro-scales. This paper investigates an innovative micro-forming technique: Laser Dynamic Forming (LDF), which induces 3-D superplastic forming in metal thin films. This forming process proceeds in a sequence of laser irradiation of ablative coating, ionization, shockwave generation and propagation in metal thin films, and conformation of metal thin films to the shape of micro/nanoscale molds. Because the deformation proceeds at ultrahigh strain rate, it is found that materials experience superplastic deformation at microscales. In this paper, experiments are carried out to understand the deformation characteristics of LDF. The shapes of the formed samples are characterized by scanning electron microscopy (SEM) and optical profilometer. The thickness variations are characterized by slicing the cross section using focused ion beam (FIB). The magnitude of deformation depth in LDF is determined primarily by three critical factors: thin film thickness, geometry of molds, and laser intensity. The relationships between laser intensity, film thickness, and mold size are explored in process maps to find out suitable processing conditions of LDF. Nanoindentation testings are conducted to show that the mechanical properties (hardness and yield strength) are increased significantly after LDF.

The Effect of Film Thickness on Stress and Transformation Behavior in Cobalt Thin Films

1999 ◽  
Vol 594 ◽  
Author(s):  
H. Th. Hesemann ◽  
P. Müllner ◽  
O. Kraft ◽  
E. Arzt
Keyword(s):  
Thin Films ◽  
Martensitic Transformation ◽  
Film Thickness ◽  
Focused Ion Beam ◽  
Ion Beam ◽  
Film Stress ◽  
Maximum Temperature ◽  
Face Centered Cubic ◽  
Temperature Cycles ◽  
Si Substrates

AbstractPure cobalt shows a martensitic transformation from a face-centered-cubic to an hexagonal-close-packed phase. In this work it is chosen as a model-system to investigate the influence of film thickness, film stress and microstructure on the martensitic transformation in thin films.Co films of 0.2 μm to 3.0 μm thickness were sputter-deposited on Si substrates. This paper presents wafer curvature measurements during temperature cycles of these films and results obtained by focused ion beam microscopy. Upon repeated thermocycling, the martensitic transformation was repeatedly observed in 3 μm thick films, whereas it was not found in 0.2 μm Co films. A stress drop on heating as well as on cooling accompanied the martensitic transformation. It was observed that the stress level at which the transformation occurs can be changed by varying the film thickness or maximum temperature of the temperature cycles. As a result, the martensitic start temperature decreases with increasing stress. It is concluded that the film stress is a critical parameter which strongly affects the martensitic transformation.

Room Temperature Recrystallization of Electroplated Copper Thin Films: Methods and Mechanisms

2000 ◽  
Vol 612 ◽  
Author(s):  
D. Walther ◽  
M. E. Gross ◽  
K. Evans-Lutterodt ◽  
W. L. Brown ◽  
M. Oh ◽  
...  
Keyword(s):  
Film Thickness ◽  
Sheet Resistance ◽  
Room Temperature ◽  
Focused Ion Beam ◽  
Ion Beam ◽  
High Surface ◽  
Volume Ratio ◽  
Data Sets ◽  
Pole Figures ◽  
Electroplated Copper

AbstractWe report a comparison of the room temperature recrystallization of electroplated (EP) copper in blanket films as a function of thickness measured by focused ion beam (FIB) microscope images and sheet resistance measurements. Both sets of data show an increase in rate with film thickness from 0.75νm up to 5νm, while little recrystallization is observed in films thinner than 0.75νm. Interestingly, the recrystallization rates from FIB analysis are consistently faster than those from the sheet resistance measurements. These data suggest that the recrystallization is initiated close to the top surface of the EP Cu film, but that in thinner films a high surface-to-volume ratio allows surface inhibition or pinning to retard the transformation. A Johnson-Mehl-AvramiKolmogorov (JMAK) analysis of the two data sets yields unusually high values for the Avrami exponent μ of up to 7 for the FIB data, while lower values of around 4 are obtained for the sheet resistance data. X-ray diffraction pole figures of the films have also been collected and correlations between the crystallographic texture, film thickness and recrystallization are discussed.

Microstructure And Mechanical Properties Of Electroplated Cu Films For Damascene Ulsi Metallization

1997 ◽  
Vol 505 ◽  
Author(s):  
V. M. Dubin ◽  
G. Morales ◽  
C. Ryu ◽  
S. S. Wong
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Standard Deviation ◽  
Aspect Ratio ◽  
High Deposition Rate ◽  
Cu Films ◽  
Copper Electroplating ◽  
Cu Film ◽  
Excellent Adhesion ◽  
Electroplated Copper

ABSTRACTCopper has been deposited for filling sub-0.5 μm trenches by using electroplating. Electroplating with pulse plating conditions provides the high deposition rate (0.5–1 μm/min) and defect-free filling the 0.25 μm trenches and vias of high aspect ratio (>4:1). Enhanced copper electroplating at the trench bottom has been achieved. The median grain size of electroplated copper was measured to be about 1 jim and the lognormal standard deviation is about 0.4 μm. Strong <111> texture was observed in electroplated Cu film. Low stress of electroplated Cu films and excellent adhesion of plated Cu to sputtered Cu seed were observed.

scholarly journals Microstructure and Mechanical Properties of Electroplated Cu Thin Films

2000 ◽  
Vol 649 ◽  
Author(s):  
A.A. Volinsky ◽  
J. Vella ◽  
I.S. Adhihetty ◽  
V. Sarihan ◽  
L. Mercado ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Elastic Modulus ◽  
Focused Ion Beam ◽  
Ion Beam ◽  
Single Crystal Silicon ◽  
Tensile Tests ◽  
Crystal Silicon ◽  
Cu Films ◽  
Force Microscopy ◽  
Atomic Force

ABSTRACTCopper films of different thicknesses of 0.2, 0.5, 1 and 2 microns were electroplated on top of the adhesion-promoting barrier layers on <100> single crystal silicon wafers. Controlled Cu grain growth was achieved by annealing films in vacuum.The Cu film microstructure was characterized using Atomic Force Microscopy and Focused Ion Beam Microscopy. Elastic modulus of 110 to 130 GPa and hardness of 1 to 1.6 GPa were measured using the continuous stiffness option (CSM) of the Nanoindenter XP. Thicker films appeared to be softer in terms of the lower modulus and hardness, exhibiting a classical Hall-Petch relationship between the yield stress and grain size. Lower elastic modulus of thicker films is due to the higher porosity and partially due to the surface roughness. Comparison between the mechanical properties of films on the substrates obtained by nanoindentation and tensile tests of the freestanding Cu films is made.

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