Properties and Barrier Material Interactions of Electroless Copper used for Seed Enhancement

2003 ◽  
Vol 766 ◽  
Author(s):  
C. Witt ◽  
K. Pfeifer
Keyword(s):  
At Risk ◽  
Physical Vapor Deposition ◽  
Copper Ion ◽  
Copper Film ◽  
Copper Films ◽  
Hydrogen Incorporation ◽  
Barrier Materials ◽  
Barrier Films ◽  
Electroless Copper ◽  
Electroplated Copper

AbstractThe conventionally used sequence for copper damascene metallization consists of barrier deposition, physical vapor deposition (PVD) Cu seed and electroplated copper. Due to the limited step coverage of PVD copper, the extendibility of this sequence to feature dimensions below 90 nm is at risk. To reduce the risk of pinch-off of very small features, the PVD layer thickness will be reduced well below 100 nm, the drawback being poor seed coverage at the bottom of the features. Void free fill by electroplating is hence at risk by both pinch-off and discontinuous seed coverage (3-5). In this paper, the use of a conformal metal deposition method, electroless copper, to enhance PVD seed layers as thin as 10 nm is presented. It is demonstrated that sparse, discontinuous copper films provide a catalytic surface for electroless copper deposition. With electroless copper, void-free copper fill of 12.5 aspect ratio (AR) trenches (70 nm width) and 8.3 AR vias is achieved. Furthermore, 6 nm thin electroless copper films were integrated in a dual damascene process and electrically characterized. A yield of approximately 85% was achieved on via chains (360000 links, 0.25 by 1.1 μm vias), with 10 nm PVD seed. This was comparable to the yield when using 100 nm PVD seed. Hydrogen, generated as a byproduct during the electroless copper ion reduction, was found in the copper deposits as well as in the barrier films underneath. In some cases, spontaneous blistering in the plated copper film was observed, and is believed to be due to hydrogen incorporation. The interaction of electroless copper films with various barrier materials (PVD Ta, PVD TaN, CVD TiN(Si) and combinations) is discussed. Electromigration test results presented in this paper indicate that the failure mechanism is not qualitatively different from reference samples with the conventional PVD seed.

Room Temperature Self-Annealing of Electroplated and Sputtered Copper Films

1999 ◽  
Vol 562 ◽  
Author(s):  
Michelle Chen ◽  
Suraj Rengarajan ◽  
Peter Hey ◽  
Yezdi Dordi ◽  
Hong Zhang ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Room Temperature ◽  
Copper Film ◽  
Copper Films ◽  
Organic Additives ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Electroplated Copper ◽  
Effect Of Copper

ABSTRACTSelf-annealing properties of electroplated and sputtered copper films at room temperature were investigated in this study, in particular, the effect of copper film thickness, electrolyte systems used, as well as their level of organic additives for electroplating. Real-time grain growth was observed by transmission electron microscopy. Sheet resistance and X-ray diffraction measurements further confirmed the recrystallization of the electroplated copper film with time. The recrystallization of electroplated films was then compared with that of sputtered copper films.

Room Temperature Self-Annealing of Electroplated and Sputtered Copper Films

1999 ◽  
Vol 564 ◽  
Author(s):  
Michelle Chen ◽  
Suraj Rengarajan ◽  
Peter Hey ◽  
Yezdi Dordi ◽  
Hong Zhang ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Room Temperature ◽  
Copper Film ◽  
Copper Films ◽  
Organic Additives ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Electroplated Copper ◽  
Effect Of Copper

AbstractSelf-annealing properties of electroplated and sputtered copper films at room temperature were investigated in this study, in particular, the effect of copper film thickness, electrolyte systems used, as well as their level of organic additives for electroplating. Real-time grain growth was observed by transmission electron microscopy. Sheet resistance and X-ray diffraction measurements further confirmed the recrystallization of the electroplated copper film with time. The recrystallization of electroplated films was then compared with that of sputtered copper films.

Barrier Effect on Electroplated Cu Films

1999 ◽  
Vol 564 ◽  
Author(s):  
R. Faust ◽  
Q. Jiang
Keyword(s):  
Room Temperature ◽  
Copper Films ◽  
Barrier Effect ◽  
Barrier Material ◽  
Dramatic Effect ◽  
Cu Films ◽  
Barrier Materials ◽  
Electroplated Copper

AbstractThe effect of various barrier materials on the microstructure of electroplated Copper films was investigated. Analysis of the Cu was performed at the as-deposited, room temperature stabilized, and annealed states. It shows that the barrier material can have a dramatic effect on the properties of electroplated Cu.

scholarly journals Analysis of stress/strain in Electroless Copper Films

2013 ◽  
Vol 2013 (1) ◽  
pp. 000026-000030 ◽  
Author(s):  
Tobias Bernhard ◽  
Simon Bamberg ◽  
Frank Brüning ◽  
Ralf Brüning ◽  
Laurence J. Gregoriades ◽  
...  
Keyword(s):  
Compressive Stress ◽  
Copper Film ◽  
Theoretical Concept ◽  
Composition Gradient ◽  
Stress Profile ◽  
Copper Films ◽  
X Ray Diffraction ◽  
Polymer Substrates ◽  
Electroless Copper ◽  
Strain Stress

Polymer substrates were chemically coated with copper using various electroless copper baths and the internal strain/stress, as well as the adhesion quality, in the resulting copper films were studied during and after deposition as a function of the deposit thickness and the operation parameters of the electroless bath. The appearance of internal compressive stress in the copper film correlates to the probability of buckle driven delamination failure (blistering). Based on a simple theoretical concept we derived limits of allowed compressive stress in the copper film without inducing this failure mode. Furthermore depth-resolved X-ray diffraction (XRD) measurements in up to 1 μm thick electroless films indicate an approximately linear internal stress profile from about +200 MPa tensile stress at the substrate/adsorbate interface to −100 MPa compressive stress at the surface of the deposit. This will be explained in terms of a possible composition gradient of nickel in the copper film.

Strain in Electroless Copper Films: Analysis by in situ X-Ray Diffraction and Curvature Methods

2013 ◽  
Vol 2013 (DPC) ◽  
pp. 001358-001388
Author(s):  
Simon Bamberg ◽  
Tobias Bernhard (corresponding author) ◽  
Laurence J. Gregoriades (presenting author) ◽  
Frank Brüning ◽  
Ralf Brüning ◽  
...  
Keyword(s):  
Tensile Stress ◽  
Copper Film ◽  
Film Stress ◽  
Copper Films ◽  
X Ray Diffraction ◽  
X Ray ◽  
Wide Range ◽  
Electroless Copper ◽  
The Difference

Strain in chemically deposited copper films on polymer substrates was determined by means of in situ X-ray diffraction (XRD), deposit stress analyzer (DSA) and spiral contractometer (SC). The strain evolution of the films was studied as a function of copper film thickness and electroless copper bath parameters, during and after deposition. The results are not indicative of a preferred crystallite orientation or texturing in the deposit. The copper film stress is controllable over a wide range of some 100 MPa from compressive to tensile stress by appropriate variation of bath parameters (e.g. temperature, concentration of bath components such as nickel, stabilizer and formaldehyde). A higher tendency of blister generation for relaxed or compressively stressed films is apparent, which implies that a sufficient level of tensile stress throughout the deposition promotes film adhesion. An observable change from tensile to compressive film stress during the cooling of the sample from bath operation to rinse water temperature is discussed in terms of substrate-induced thermal stress to the copper film. In this context, the difference in the substrate materials required for XRD (polymer), DSA (copper) and SC (stainless steel) may be a significant factor contributing to the diverging measured stress behaviors of the methods. Moreover, it is questionable whether SC stress data can be compared with XRD and DSA stress data, due to the low resolution of the SC method (~60 MPa).

Effect of barrier layers on the texture and microstructure of Copper films

2003 ◽  
Vol 766 ◽  
Author(s):  
Tejodher Muppidi ◽  
David P Field
Keyword(s):  
Barrier Layer ◽  
Copper Film ◽  
Copper Films ◽  
Microstructure Development ◽  
Deposition Technique ◽  
Barrier Layers ◽  
Barrier Films ◽  
Final Microstructure ◽  
Layer Stacking ◽  
Interconnect Material

AbstractThe microstructure of interconnect material is know to influence its electromigration and stress-voiding properties. In addition to many factors responsible for the microstructure development, the barrier layer could be a major contributing factor as it forms the substrate for the copper films above. The microstructure of the barrier films based on its deposition technique could determine the final microstructure of the copper film. In the present work we examine the effect of two different barrier layers (Ta and TaN) and different stackings of these two materials on the microstructure on the copper seed (PVD) and electroplated films using EBSD, AFM and XRD. The results show that the plated films have a predominantly (111) texture and uniform grain size. But the (111) texture maximum varied with the barrier layer stacking underneath the plated film.

The Study of Specific Materials Used by the Copper Wiring CMP of GLSI

2013 ◽  
Vol 307 ◽  
pp. 368-371
Author(s):  
Yu Ling Liu ◽  
Juan Wang ◽  
Bao Hong Gao
Keyword(s):  
High Speed ◽  
Chelating Agents ◽  
Active Agent ◽  
Copper Ion ◽  
Copper Film ◽  
Steel Corrosion ◽  
New Material ◽  
Ph Buffer ◽  
Materials Used ◽  
Acidic Oxides

In this paper, the multi-hydroxyl polyamines researched by ourselves are used in the slurry of the copper wiring CMP of GLSI, which makes the slurry alkalization. It also has the using as a pH adjusting agent, complexion agent of copper ion, multi- metal chelating agents, aminating agent of acidic oxides, pH buffer, stainless steel corrosion inhibitor, the active agent and pro-oxidant. It improves the property of slurry and solves many different of acidity slurry. The alkalinity slurry contained the multi-hydroxyl polyamines is environmental, inexpensive and composition- simplified. Without the toxic BTA which is must be used in the international and has side effect, the slurry can achieve the high speed and high flat. In the same time the low pressure and the little abrasive can be realized, which provide the new material for the removal of TSV copper film.

Adhesion mechanisms of copper films deposited onto laser-irradiated alumina

1997 ◽  
Vol 12 (11) ◽  
pp. 3174-3181 ◽  
Author(s):  
Jae-Won Park ◽  
Anthony J. Pedraza ◽  
Douglas H. Lowndes ◽  
William R. Allen
Keyword(s):  
Laser Irradiation ◽  
Copper Film ◽  
Alumina Substrate ◽  
Interfacial Region ◽  
Transitional Region ◽  
Copper Films ◽  
High Adhesion ◽  
Strong Adhesion ◽  
Oxygen Excess ◽  
Higher Temperature

Strong adhesion between a deposited copper film and an alumina substrate takes place when the substrate is laser-irradiated prior to deposition. A post-deposition annealing is required to achieve the strong bonding. In this work, the interfacial region between the copper film and the alumina substrate was analyzed using Auger Electron Spectroscopy (AES). It was found that a transitional region is always present in couples that have a high adhesion strength, while little or no transitional region was found in weakly bonded couples. The transitional region depends on the laser irradiation atmosphere. In the case of laser irradiation in air, oxygen excess was found on the surface of the alumina substrate, and in the copper/alumina couple the transitional region consists of a copper oxide and a Cu–Al double oxide. When the laser irradiation was performed in a reducing atmosphere (Ar–4% H2), substoichiometric alumina and metallic aluminum were found on the surface of the substrate and also a reaction between copper and the substoichiometric aluminum oxide was detected in the subsurface. Although the substoichiometric alumina is formed on the surface irradiated in Ar–4% H2, a stable Al2O3 thin layer is formed on the outmost surface because the irradiated substrate is exposed to the atmosphere before deposition. This reoxidized layer remains whole at the interface of the couple upon low temperature (at least up to 300 °C) annealing, while it is ruptured upon higher temperature annealing (500 °C in this work). In the latter case, the copper film can contact and react with the substoichiometric alumina formed in the subsurface of the substrate irradiated in the Ar–4% H2 atmosphere. It is concluded that the Cu–Al–O interfacial compound formed in the transitional region causes the strong adhesion between the copper film and the alumina substrate.

Constitutive Response of Passivated Copper Films: Experiments and Analyses

2001 ◽  
Vol 695 ◽  
Author(s):  
Y.-L. Shen ◽  
U. Ramamurty
Keyword(s):  
Thermal Loading ◽  
Silicon Oxide ◽  
Kinematic Hardening ◽  
Copper Film ◽  
Temperature Response ◽  
Copper Interconnects ◽  
Constitutive Law ◽  
Copper Films ◽  
Rate Dependent ◽  
Constitutive Response

ABSTRACTThe constitutive behavior of passivated copper films is studied. Stresses in copper films of thickness ranging from 1000 nm to 40 nm, passivated with silicon oxide on a quartz or silicon substrate, were measured using the curvature method. The thermal cycling spans a temperature range from - 196 to 600°C. It is seen that the strong relaxation at high temperatures normally found in unpassivated films is nonexistent for passivated films. The copper film did not show any rate-dependent effect over a range of heating/cooling rate from 5 to 25°C/min. Further analyses showed that significant strain hardening exists during the course of thermal loading. In particular, the measured stress- temperature response can only be fitted with a kinematic hardening model, if a simple constitutive law within the continuum plasticity framework is to be used. The analytic procedures for extracting the film properties are presented. Implications to stress modeling of copper interconnects in actual devices are discussed.

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