Isothermal Stress Relaxation in Al, Alcu and A1vpd Films

1996 ◽  
Vol 436 ◽  
Author(s):  
J. P. Lokker ◽  
J. F. Jongste ◽  
G. C. A. M. Janssen ◽  
S. Radelaar
Keyword(s):  
Stress Relaxation ◽  
Integrated Circuits ◽  
Tensile Stress ◽  
Thermal Cycling ◽  
Mechanical Behavior ◽  
Mechanical Stress ◽  
Plasma Etching ◽  
Isothermal Treatment ◽  
Aluminum Metallization ◽  
Curvature Measurements

AbstractMechanical stress and its relaxation in aluminum metallization in integrated circuits (IC) are a major concern for the reliability of the material. It is known that adding Cu improves the reliability but complicates plasma etching and increases corrosion sensitivity. The mechanical behavior of AlVPd, AlCu and Al blanket films is investigated by wafer curvature measurements. During thermal cycling between 50°C and 400°C the highest tensile stress is found in AlVPd. In a subsequent experiment, the cooling was interrupted at several temperatures to investigate the stress behavior during an eight hour isothermal treatment. Isothermal stress relaxation has been observed in the three types of films and is discussed.

Isothermal Stress Relaxation In Al, AlCu and AlVPd Films

1996 ◽  
Vol 428 ◽  
Author(s):  
J. P. Lokker ◽  
J. F. Jongste ◽  
G. C. A. M. Janssen ◽  
S. Radelaar
Keyword(s):  
Stress Relaxation ◽  
Integrated Circuits ◽  
Tensile Stress ◽  
Thermal Cycling ◽  
Mechanical Behavior ◽  
Mechanical Stress ◽  
Plasma Etching ◽  
Isothermal Treatment ◽  
Aluminum Metallization ◽  
Curvature Measurements

AbstractMechanical stress and its relaxation in aluminum metallization in integrated circuits (IC) are a major concern for the reliability of the material. It is known that adding Cu improves the reliability but complicates plasma etching and increases corrosion sensitivity. The mechanical behavior of AIVPd, AlCu and Al blanket films is investigated by wafer curvature measurements. During thermal cycling between 50°C and 400°C the highest tensile stress is found in AIVPd. In a subsequent experiment, the cooling was interrupted at several temperatures to investigate the stress behavior during an eight hour isothermal treatment. Isothermal stress relaxation has been observed in the three types of films and is discussed.

The Effect of Ultra-Low Temperature Treatments on the Stress in Aluminum Metallization on Silicon Wafers

1994 ◽  
Vol 338 ◽  
Author(s):  
Frank Baldwin ◽  
Paul H. Holloway ◽  
Mark Bordelon ◽  
Thomas R. Watkins
Keyword(s):  
Stress Relaxation ◽  
Low Temperature ◽  
Thermal Cycling ◽  
Liquid Nitrogen ◽  
Room Temperature ◽  
Silicon Wafers ◽  
X Ray Diffraction ◽  
X Ray ◽  
Aluminum Metallization ◽  
Low Temperature Treatments

ABSTRACTThe stresses in Al-0.75w%Si-0.5w%Cu unpatterned metallization on silicon wafers have been measured using substrate curvature and x-ray diffraction techniques after quenching in liquid nitrogen. Stresses were measured with and without phospho-silicate glass overlayers and SiO2 underlayers, and thermal cycling followed by relaxation at room temperature. It was found that cooling the substrates to 77 K and warming to room temperature caused the metallization stress to go from tensile to compressive. Subsequent heating of the substrates to above ∼70°C followed by cooling to room temperature caused the stress to become tensile. Both compressive and tensile stresses were found to relax at room temperature with a time constant of 2.3 ± 0.2 hours. The magnitude of stress relaxation was a function of temperature, being about 20 MPa after heating to 240°C. The metallization exhibited both compressive and tensile flow stresses of ∼100 MPa near room temperature.

Mechanical Behavior of Eutectic Sn-Ag and Sn-Zn Solders

1995 ◽  
Vol 390 ◽  
Author(s):  
Hareesh Mavoori ◽  
Semyon Vaynman ◽  
Jason Chin ◽  
Brian Moran ◽  
Leon M. Keer ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Numerical Simulation ◽  
Stress Relaxation ◽  
Tensile Stress ◽  
Mechanical Behavior ◽  
Constitutive Modeling ◽  
Empirical Modeling ◽  
Damage Models ◽  
Simulation Based ◽  
Semi Empirical

ABSTRACTEutectic Sn-Ag and Sn-Zn solders are currently being investigated as the basis for replacement of Sn-Pb solders. Some mechanical properties of these solder systems - fatigue, tensile, stress relaxation and creep are presented here along with some damage feature observations for eutectic Sn-Ag solder. Semi-empirical modeling, constitutive modeling and numerical simulation based on damage models have been carried out for lifetime prediction. Preliminary agreement of this numerical simulation with experimental results appears encouraging, but the models need further refinement.

Stress Relaxation in Al–Cu and Al–Si–Cu Thin Films

1999 ◽  
Vol 14 (4) ◽  
pp. 1246-1254 ◽  
Author(s):  
A. Witvrouw ◽  
J. Proost ◽  
Ph. Roussel ◽  
P. Cosemans ◽  
K. Maex
Keyword(s):  
Stress Relaxation ◽  
Thermal Cycling ◽  
Thermal Cycle ◽  
Room Temperature ◽  
Relaxation Data ◽  
Cu Films ◽  
Dislocation Glide ◽  
Transmission Electron ◽  
Stress Changes ◽  
Curvature Measurements

Substrate curvature measurements were used to study stress changes during thermal cycling and isothermal tensile stress relaxation in 800 nm Al–0.5 wt% Cu and Al–1 wt% Si–0.5 wt% Cu films. For both compositions dislocation glide can describe the relaxation data well for temperatures up to 120 °C for Al–Si–Cu and up to 100 °C for Al–Cu. The average activation energy for Al–Si–Cu and Al–Cu is 1.7 ± 0.2 eV and 3.0 ± 0.3 eV, respectively. The athermal flow stress is the same for both and equal to 600 ± 200 MPa. This result is consistent with the obstacles for glide being Al2Cu precipitates, which, in the case of Al–Si–Cu, are fine and can be cut by the dislocations, and, in the case of Al–Cu, are strong and provide Orowan strengthening. Also, the stress changes during thermal cycling in the Al–Cu films are different from those in the Al–Si–Cu films. For Al–Cu films, the room temperature stress decreases after each thermal cycle, while for Al–Si–Cu stress changes during thermal cycling are stable from the second cycle on. These observations are supported by thorough transmission electron microscopy (TEM) studies.

The Formation of TiN-Encapsulated Cu Interconnects

1992 ◽  
Vol 260 ◽  
Author(s):  
Jian Li ◽  
J. W. Strane ◽  
S. W. Russell ◽  
P. Chapman ◽  
Y. Shacham-Diamand ◽  
...  
Keyword(s):  
Stress Relaxation ◽  
Tensile Stress ◽  
Thermal Cycling ◽  
Copper Film ◽  
Alloy Film ◽  
Ti Alloy ◽  
Good Adhesion ◽  
Adhesion Layer ◽  
Fast Heating ◽  
Copper Structure

ABSTRACTA TiN(0)-encapsulated copper structure was made by annealing a Cu-10 at%Ti alloy film evaporated on a SiO2/Si(100) substrate in N2 or NH3 ambiente. During thermal cycling, the tensile stress in the nitridated films is in the range of 200 to 800 MPa. The stress relaxation depends on the cooling cycle and the presence of interlayer between film and substrate. A fast heating rate (70°C/min.) to 550°C in an NH3 ambient can effectively suppress the formation of Cu3Ti and enhance the TiNχ(0) formation near the surface of the copper film. This self-encapsulated Cu structure exhibits good adhesion to SiO2 and oxidation resistance. A fully encapsulated Cu fine line structure can be achieved by annealing a Cu-10at%Ti alloy film in an Ar ambient at 550°C and then in an NH3 ambient at 550°C to form TiOχ/Ti5Si3 adhesion layer and TiN(O) layer, respectively.

Stress Relaxation and the Formation of Silicides in the Process of the Crystallization of NI-NB Films on SI

1991 ◽  
Vol 49 ◽  
pp. 898-899
Author(s):  
N. Rozhanski ◽  
V. Lifshitz
Keyword(s):  
Thin Films ◽  
Stress Relaxation ◽  
Integrated Circuits ◽  
Direct Evidence ◽  
Alloy Film ◽  
Diffusion Barriers ◽  
Effective Barrier

Thin films of amorphous Ni-Nb alloys are of interest since they can be used as diffusion barriers for integrated circuits on Si. A native SiO2 layer is an effective barrier for Ni diffusion but it deformation during the crystallization of the alloy film lead to the appearence of diffusion fluxes through it and the following formation of silicides. This study concerns the direct evidence of the action of stresses in the process of the crystallization of Ni-Nb films on Si and the structure of forming NiSi2 islands.

Using the secondary electrons (SE) of SEM with NIST‘s MONSEL-II program to obtain improved linewidth measurements and slope angles of line edges on a MMIC GaAs device

1996 ◽  
Vol 54 ◽  
pp. 944-945
Author(s):  
Richard G. Sartore
Keyword(s):  
Integrated Circuits ◽  
Plasma Etching ◽  
Microwave Integrated Circuits ◽  
Monolithic Microwave Integrated Circuits ◽  
Thick Gold ◽  
Gaas Devices ◽  
Source Distance ◽  
Margin Of Error ◽  
Dimensional Measurements ◽  
Barrier Metal

In the evaluation of GaAs devices from the MMIC (Monolithic Microwave Integrated Circuits) program for Army applications, there was a requirement to obtain accurate linewidth measurements on the nominal 0.5 micrometer gate lengths used to fabricate these devices. Preliminary measurements indicated a significant variation (typically 10 % to 30% but could be more) in the critical dimensional measurements of the gate length, gate to source distance and gate to drain distance. Passivation introduced a margin of error, which was removed by plasma etching. Additionally, the high aspect ratio (4-5) of the thick gold (Au) conductors also introduced measurement difficulties. The final measurements were performed after the thick gold conductor was removed and only the barrier metal remained, which was approximately 250 nanometer thick platinum on GaAs substrate. The thickness was measured using the penetration voltage method. Linescan of the secondary electron signal as it scans across the gate is shown in Figure 1.

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